Defining VPN security policies

This section explains how to specify the source and destination IP addresses of traffic transmitted through an IPsec VPN, and how to define appropriate security policies.

The following topics are included in this section:

Defining policy addresses

Defining security policies for policy-based and route-based VPNs

Defining policy addresses

A VPN tunnel has two end points. These end points may be VPN peers such as two FortiGate gateways. Encrypted packets are transmitted between the end points. At each end of the VPN tunnel, a VPN peer intercepts encrypted packets, decrypts the packets, and forwards the decrypted IP packets to the intended destination.

You need to define firewall addresses for the private networks behind each peer. You will use these addresses as the source or destination address depending on the security policy.

policy addresses

Example topology for the following policies

In general:

• In a gateway-to-gateway, hub-and-spoke, dynamic DNS, redundant-tunnel, or transparent configuration, you need to define a policy address for the private IP address of the network behind the remote VPN peer (for example,

192.168.10.0/255.255.255.0 or 192.168.10.0/24).

• In a peer-to-peer configuration, you need to define a policy address for the private IP address of a server or host behind the remote VPN peer (for example, 16.5.1/255.255.255.255 or 172.16.5.1/32 or 172.16.5.1).

For a FortiGate dialup server in a dialup-client or Internet-browsing configuration:

• If you are not using VIP addresses, or if the FortiGate dialup server assigns VIP addresses to FortiClient dialup clients through FortiGate DHCP relay, select the predefined destination address “all” in the security policy to refer to the dialup clients.
• If you assign VIP addresses to FortiClient dialup clients manually, you need to define a policy address for the VIP address assigned to the dialup client (for example, 254.254.1/32), or a subnet address from which the VIP addresses are assigned (for example, 10.254.254.0/24 or 10.254.254.0/255.255.255.0).
• For a FortiGate dialup client in a dialup-client or Internet-browsing configuration, you need to define a policy address for the private IP address of a host, server, or network behind the FortiGate dialup server.

VPN security policies                                  Defining security policies for policy-based and route-based VPNs

Defining a security IP address

1. Go to Policy & Objects > Addresses and select Create New.
2. In the Name field, type a descriptive name that represents the network, server(s), or host(s).
3. In Type, select Subnet.
4. In the Subnet/IP Range field, type the corresponding IP address and subnet mask.

For a subnet you could use the format 172.16.5.0/24 or its equivalent 172.16.5.0/255.255.255.0. For a server or host it would likely be 172.16.5.1/32. Alternately you can use an IP address range such as

192.168.10.[80-100] or 192.168.10.80-192.168.10.100.

5. Select OK.

Defining security policies for policy-based and route-based VPNs

Security policies allow IP traffic to pass between interfaces on a FortiGate unit. You can limit communication to particular traffic by specifying source address and destination addresses. Then only traffic from those addresses will be allowed.

Policy-based and route-based VPNs require different security policies.

• A policy-based VPN requires an IPsec security policy. You specify the interface to the private network, the interface to the remote peer and the VPN tunnel. A single policy can enable traffic inbound, outbound, or in both directions.
• A route-based VPN requires an Accept security policy for each direction. As source and destination interfaces, you specify the interface to the private network and the virtual IPsec interface (Phase 1 configuration) of the VPN. The IPsec interface is the destination interface for the outbound policy and the source interface for the inbound policy. One security policy must be configured for each direction of each VPN interface.

There are examples of security policies for both policy-based and route-based VPNs throughout this guide. See Route-based or policy-based VPN on page 119.

If the security policy, which grants the VPN Connection is limited to certain services,

DHCP must be included, otherwise the client won’t be able to retrieve a lease from the FortiGate’s (IPsec) DHCP server, because the DHCP Request (coming out of the tunnel) will be blocked.

Policy-based VPN

An IPsec security policy enables the transmission and reception of encrypted packets, specifies the permitted direction of VPN traffic, and selects the VPN tunnel. In most cases, a single policy is needed to control both inbound and outbound IP traffic through a VPN tunnel. Be aware of the following considerations below before creating an IPsec security policy.

Allow traffic to be initiated from the remote site

Security policies specify which IP addresses can initiate a tunnel. By default, traffic from the local private network initiates the tunnel. When the Allow traffic to be initiated form the remote site option is selected, traffic from a dialup client, or a computer on a remote network, initiates the tunnel. Both can be enabled at the same time for bi-directional initiation of the tunnel.

security policies for policy-based and route-based VPNs

Outbound and inbound NAT

When a FortiGate unit operates in NAT mode, you can also enable inbound or outbound NAT. Outbound NAT may be performed on outbound encrypted packets or IP packets in order to change their source address before they are sent through the tunnel. Inbound NAT is performed to intercept and decrypt emerging IP packets from the tunnel.

By default, these options are not selected in security policies and can only be set through the CLI. For more information on this, see the “config firewall” chapter of the FortiGate CLI Reference.

Source and destination addresses

Most security policies control outbound IP traffic. A VPN outbound policy usually has a source address originating on the private network behind the local FortiGate unit, and a destination address belonging to a dialup VPN client or a network behind the remote VPN peer. The source address that you choose for the security policy identifies from where outbound cleartext IP packets may originate, and also defines the local IP address or addresses that a remote server or client will be allowed to access through the VPN tunnel. The destination address that you choose identifies where IP packets must be forwarded after they are decrypted at the far end of the tunnel, and determines the IP address or addresses that the local network will be able to access at the far end of the tunnel.

Enabling other policy features

You can fine-tune a policy for services such as HTTP, FTP, and POP3, enable logging, traffic shaping, antivirus protection, web filtering, email filtering, file transfer, email services, and optionally allow connections according to a predefined schedule.

As an option, differentiated services (diffserv or DSCP) for the security policy can be enabled through the CLI. For more information on this feature, see the Traffic Shaping handbook chapter,  or the “firewall” chapter of the FortiGate CLI Reference.

Before you begin

Before you define the IPsec policy, you must:

• Define the IP source and destination addresses. See Defining policy addresses on page 78.
• Specify the Phase 1 authentication parameters. See Phase 1 parameters on page 52.
• Specify the Phase 2 parameters. See Phase 2 parameters on page 72.

Defining an IPsec security policy

1. Go to Policy & Objects > IPv4 Policy.
2. Select Create New and set the following options:

VPN security policies                                  Defining security policies for policy-based and route-based VPNs

3. You may enable UTM features, and/or event logging, or select advanced settings to authenticate a user group, or shape traffic. For more information, see the Firewall handbook chapter.
4. Select OK.
5. Place the policy in the policy list above any other policies having similar source and destination addresses.

Defining multiple IPsec policies for the same tunnel

You must define at least one IPsec policy for each VPN tunnel. If the same remote server or client requires access to more than one network behind a local FortiGate unit, the FortiGate unit must be configured with an IPsec policy for each network. Multiple policies may be required to configure redundant connections to a remote destination or control access to different services at different times.

To ensure a secure connection, the FortiGate unit must evaluate policies with Action set to IPsec  before

ACCEPT and DENY. Because the FortiGate unit reads policies starting at the top of the list, you must move all IPsec policies to the top of the list, and be sure to  reorder your multiple IPsec policies that apply to the tunnel so that specific constraints can be evaluated before general constraints.

Adding multiple IPsec policies for the same VPN tunnel can cause conflicts if the policies specify similar source and destination addresses, but have different settings for the same service. When policies overlap in this manner, the system may apply the wrong IPsec policy or the tunnel may fail.

For example, if you create two equivalent IPsec policies for two different tunnels, it does not matter which one comes first in the list of IPsec policies — the system will select the correct policy based on the specified source and destination addresses. If you create two different IPsec policies for the same tunnel (that is, the two policies treat traffic differently depending on the nature of the connection request), you might have to reorder the IPsec policies to ensure that the system selects the correct IPsec policy.

Route-based VPN

When you define a route-based VPN, you create a virtual IPsec interface on the physical interface that connects to the remote peer. You create ordinary Accept security policies to enable traffic between the IPsec interface and the interface that connects to the private network. This makes configuration simpler than for policy-based VPNs, which require IPsec security policies.

security policies for policy-based and route-based VPNs

Defining security policies for a route-based VPN

1. Go to Policy & Objects > IPv4 Policy.
2. Select Create New and define an ACCEPT security policy to permit communication between the local private network and the private network behind the remote peer. Enter these settings in particular:

To permit the remote client to initiate communication, you need to define a security policy for communication in that direction.

3. Select Create New and enter these settings in particular:

Gateway-to-gateway

This section explains how to set up a basic gateway-to-gateway (site-to-site) IPsec VPN.

The following topics are included in this section:

Configuration overview

Gateway-to-gateway configuration

How to work with overlapping subnets Testing

Configuration overview

In a gateway-to-gateway configuration, two FortiGate units create a VPN tunnel between two separate private networks. All traffic between the two networks is encrypted and protected by FortiGate security policies.

Example gateway-to-gateway configuration

In some cases, computers on the private network behind one VPN peer may (by co-incidence) have IP addresses that are already used by computers on the network behind the other VPN peer. In this type of situation

(ambiguous routing), conflicts may occur in one or both of the FortiGate routing tables and traffic destined for the remote network through the tunnel may not be sent. To resolve issues related to ambiguous routing, see Configuration overview on page 84.

Configuration overview

In other cases, computers on the private network behind one VPN peer may obtain IP addresses from a local DHCP server. However, unless the local and remote networks use different private network address spaces, unintended ambiguous routing and/or IP-address overlap issues may arise. For a discussion of the related issues, see FortiGate dialup-client configurations  on page 1.

Configuration overview

You can set up a fully meshed or partially meshed configuration (see below).

Fully meshed configuration

In a fully meshed network, all VPN peers are connected to each other, with one hop between peers. This topology is the most fault-tolerant: if one peer goes down, the rest of the network is not affected. This topology is difficult to scale because it requires connections between all peers. In addition, unnecessary communication can occur between peers. Best practices dictates a hub-and-spoke configuration instead (see Hub-and-spoke configurations on page 1).

Partially meshed configuration

A partially meshed network is similar to a fully meshed network, but instead of having tunnels between all peers, tunnels are only configured between peers that communicate with each other regularly.

Gateway-to-gateway configuration

The FortiGate units at both ends of the tunnel must be operating in NAT mode and have static public IP addresses.

When a FortiGate unit receives a connection request from a remote VPN peer, it uses IPsec Phase 1 parameters to establish a secure connection and authenticate that VPN peer. Then, if the security policy permits the connection, the FortiGate unit establishes the tunnel using IPsec Phase 2 parameters and applies the IPsec security policy. Key management, authentication, and security services are negotiated dynamically through the IKE protocol.

To support these functions, the following general configuration steps must be performed by both FortiGate units:

• Define the Phase 1 parameters that the FortiGate unit needs to authenticate the remote peer and establish a secure connection.
• Define the Phase 2 parameters that the FortiGate unit needs to create a VPN tunnel with the remote peer.
• Create security policies to control the permitted services and permitted direction of traffic between the IP source and destination addresses.

Gateway-to-gateway configuration

Configuring Phase 1 and Phase 2 for both peers

This procedure applies to both peers. Repeat the procedure on each FortiGate unit, using the correct IP address for each. You may wish to vary the Phase 1 names but this is optional. Otherwise all steps are the same for each peer.

The Phase 1 configuration defines the parameters that FortiGate_1 will use to authenticate FortiGate_2 and establish a secure connection. For the purposes of this example, a preshared key will be used to authenticate FortiGate_2. The same preshared key must be specified at both FortiGate units. Before you define the Phase 1 parameters, you need to:

• Reserve a name for the remote gateway.
• Obtain the IP address of the public interface to the remote peer. l Reserve a unique value for the preshared key.

The key must contain at least 6 printable characters and best practices dictate that it only be known by network administrators. For optimum protection against currently known attacks, the key must have a minimum of 16 randomly chosen alphanumeric characters.

At the local FortiGate unit, define the Phase 1 configuration needed to establish a secure connection with the remote peer. See IPsec VPN in the web-based manager on page 38.

1. Go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit the Phase 1 Proposal (if it is not available, you may need to click the Convert to Custom Tunnel button). Enter the following information, and select OK.

The basic Phase 2 settings associate IPsec Phase 2 parameters with the Phase 1 configuration and specify the remote end point of the VPN tunnel. Before you define the Phase 2 parameters, you need to reserve a name for the tunnel. See IPsec VPN in the web-based manager on page 38.

1. Open the Phase 2 Selectors panel (if it is not available, you may need to click the Convert to Custom Tunnel button).
2. Enter a Name of peer_1_p2.
3. Select peer_1 from the Phase 1 drop-down menu.

Creating security policies

Security policies control all IP traffic passing between a source address and a destination address.

An IPsec security policy is needed to allow the transmission of encrypted packets, specify the permitted direction of VPN traffic, and select the VPN tunnel that will be subject to the policy. A single policy is needed to control both inbound and outbound IP traffic through a VPN tunnel.

Before you define security policies, you must first specify the IP source and destination addresses. In a gatewayto-gateway configuration:

• The IP source address corresponds to the private network behind the local FortiGate unit. l The IP destination address refers to the private network behind the remote VPN peer.

When you are creating security policies, choose one of either route-based or policy-based methods and follow it for both VPN peers. DO NOT configure both route-based and policy-based policies on the same FortiGate unit for the same VPN tunnel.

The configuration of FortiGate_2 is similar to that of FortiGate_1. You must:

• Define the Phase 1 parameters that FortiGate_2 needs to authenticate FortiGate_1 and establish a secure connection.
• Define the Phase 2 parameters that FortiGate_2 needs to create a VPN tunnel with FortiGate_1.
• Create the security policy and define the scope of permitted services between the IP source and destination addresses.

When creating security policies it is good practice to include a comment describing what the policy does.

Creating firewall addresses

Define names for the addresses or address ranges of the private networks that the VPN links. These addresses are used in the security policies that permit communication between the networks.

To define the IP address of the network behind FortiGate_1

1. Go to Policy & Objects > Addresses and select Create New.
2. Enter the Name of Finance_network. Select a Type of Subnet.
3. Enter the Subnet of 21.101.0/24.
4. Select OK.

To specify the address of the network behind FortiGate_2

1. Go to Policy & Objects > Addresses and select Create New.
2. Enter the Name of HR_network.
3. Select a Type of Subnet.
4. Enter the Subnet/IP Range of 31.101.0/24. 5. Select OK.

Creating route-based VPN security policies

Define an ACCEPT security policy to permit communications between the source and destination addresses.

To create route-based VPN security policies  1. Go to Policy & Objects > IPv4 Policy and select Create New

2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.

Gateway-to-gateway configuration

3. Enter the following, and select OK.

4. Optionally, configure any additional features you may want, such as UTM or traffic shaping.
5. Select Create New to create another policy for the other direction.
6. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.
7. Enter the following information, and select OK.

8. Configure any additional features such as UTM or traffic shaping you may want. (optional).

All network traffic must have a static route to direct its traffic to the proper destination. Without a route, traffic will not flow even if the security policies are configured properly. You may need to create a static route entry for both directions of VPN traffic if your security policies allow bi-directional tunnel initiation.

To configure the route for a route-based VPN:

1. On FortiGate_2, go to Network > Static Routes and select Create New.
2. Enter the following information, and then select OK:

Creating policy-based VPN security policy

Define an IPsec security policy to permit communications between the source and destination addresses.

1. Go to Policy & Objects > IPv4 Policy.
2. Complete the following:

Place VPN policies in the policy list above any other policies having similar source and destination addresses.

How to work with overlapping subnets

A site-to-site VPN configuration sometimes has the problem that the private subnet addresses at each end are the same. You can resolve this problem by remapping the private addresses using virtual IP addresses (VIP).

VIPs allow computers on those overlapping private subnets to each have another set of IP addresses that can be used without confusion. The FortiGate unit maps the VIP addresses to the original addresses. This means if PC1 starts a session with PC2 at 10.31.101.10, FortiGate_2 directs that session to 10.11.101.10 — the actual IP address of PC2.The figure below demonstrates this — Finance network VIP is 10.21.101.0/24 and the HR network is 10.31.101.0/24.

How to work with overlapping subnets

Overlapped subnets example

Solution for route-based VPN

You need to:

• Configure IPsec Phase 1 and Phase 2 as you usually would for a route-based VPN. In this example, the resulting IPsec interface is named FGT1_to_FGT2.
• Configure virtual IP (VIP) mapping:
• the 10.21.101.0/24 network mapped to the 10.11.101.0/24 network on FortiGate_1
• the 10.31.101.0/24 network mapped to the 10.11.101.0/24 network on FortiGate_2 l Configure an outgoing security policy with ordinary source NAT on both FortiGates.
• Configure an incoming security policy with the VIP as the destination on both FortiGates.
• Configure a route to the remote private network over the IPsec interface on both FortiGates.

To configure VIP mapping on both FortiGates

1. Go to Policy & Objects > Virtual IPs and create a new Virtual IP.
2. Enter the following information, and select OK:

3. Repeat this procedure on both FortiGate_1 and FortiGate_2.

To configure the outbound security policy on both FortiGates

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter the following information, and select OK:

3. Repeat this procedure on both FortiGate_1 and FortiGate_2.

To configure the inbound security policy on both FortiGates

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter the following information, and then select OK:

How to work with overlapping subnets

3. Repeat this procedure on both FortiGate_1 and FortiGate_2.

To configure the static route for both FortiGates

1. Go to Network > Static Routes and create a new Route (or IPv6 Route as necessary).
2. Enter the following information, and then select OK:

Solution for policy-based VPN

As with the route-based solution, users contact hosts at the other end of the VPN using an alternate subnet address. PC1 communicates with PC2 using IP address 10.31.101.10, and PC2 communicates with PC1 using IP address 10.21.101.10.

In this solution however, outbound NAT is used to translate the source address of packets from the

10.11.101.0/24 network to the alternate subnet address that hosts at the other end of the VPN use to reply. Inbound packets from the remote end have their destination addresses translated back to the 10.11.101.0/24 network.

For example, PC1 uses the destination address 10.31.101.10 to contact PC2. Outbound NAT on FortiGate_1 translates the PC1 source address to 10.21.101.10. At the FortiGate_2 end of the tunnel, the outbound NAT configuration translates the destination address to the actual PC2 address of 10.11.101.10. Similarly, PC2 replies to PC1 using destination address 10.21.101.10, with the PC2 source address translated to 10.31.101.10. PC1 and PC2 can communicate over the VPN even though they both have the same IP address.

You need to:

• Configure IPsec Phase 1 as you usually would for a policy-based VPN. l Configure IPsec Phase 2 with the use-natip disable CLI option.  l Define a firewall address for the local private network, 10.11.101.0/24.
• Define a firewall address for the remote private network:
• Define a firewall address for 10.31.101.0/24 on FortiGate_1
• Define a firewall address for 10.21.101.0/24 on FortiGate_2
• Configure an outgoing IPsec security policy with outbound NAT to map 10.11.101.0/24 source addresses:
• To the 10.21.101.0/24 network on FortiGate_1
• To the 10.31.101.0/24 network on FortiGate_2

To configure IPsec Phase 2 – CLI

config vpn ipsec phase2 edit “FGT1_FGT2_p2” set keepalive enable set pfs enable set phase1name FGT1_to_FGT2 set proposal 3des-sha1 3des-md5 set replay enable set use-natip disable

end

In this example, your Phase 1 definition is named FGT1_to_FGT2. use-natip is set to disable, so you can specify the source selector using the src-addr-type, src-start-ip / src-end-ip or src-subnet keywords. This example leaves these keywords at their default values, which specify the subnet 0.0.0.0/0.

The pfs keyword ensures that perfect forward secrecy (PFS) is used. This ensures that each Phase 2 key created is unrelated to any other keys in use.

To define the local private network firewall address

1. Go to Policy & Objects > Addresses and create a new Address. 2. Enter the following information and select OK.

To define the remote private network firewall address

1. Go to Policy & Objects > Addresses and create a new Address.
2. Enter the following information, and select OK:

Testing

To configure the IPsec security policy

In the CLI on FortiGate_1, enter the commands:

config firewall policy edit 1 set srcintf “port1” set dstintf “port2” set srcaddr “vpn-local” set dstaddr “vpn-remote” set action ipsec set schedule “always” set service “ANY” set inbound enable set outbound enable set vpntunnel “FGT1_to_FGT2” set natoutbound enable

set natip 10.31.101.0 255.255.255.0

end

Optionally, you can set everything except natip in the web-based manager and then use the CLI to set natip.

Enter the same commands on FortiGate_2, but set natip be 10.21.101.0 255.255.255.0.

Testing

The best testing is to look at the packets both as the VPN tunnel is negotiated, and when the tunnel is up.

Determining what the other end of the VPN tunnel is proposing

1. Start a terminal program such as PuTTY and set it to log all output.

When necessary refer to the logs to locate information when output is verbose.

2. Logon to the FortiGate unit using a super_admin account.
3. Enter the following CLI commands.
4. Display all the possible IKE error types and the number of times they have occurred:

diag vpn ike errors

5. Check for existing debug sessions:

diag debug info

Testing

If a debug session is running, to halt it enter:

diag debug disable

6. Confirm your proposal settings:

diag vpn ike config list

7. If your proposal settings do not match what you expect, make a change to it and save it to force an update in memory. If that fixes the problem, stop here.
8. List the current vpn filter:

diag vpn ike filter

9. If all fields are set to any, there are no filters set and all VPN IKE packets will be displayed in the debug output. If your system has only a few VPNs, skip setting the filter.

If your system has many VPN connections this will result in very verbose output and make it very difficult to locate the correct connection attempt.

10. Set the VPN filter to display only information from the destination IP address for example 10.10.10.10:

diag vpn ike log-filter dst-addr4 10.10.10.10

To add more filter options, enter them one per line as above. Other filter options are:

11. Start debugging:

diag debug app ike 255 diag debug enable

12. Have the remote end attempt a VPN connection.

If the remote end attempts the connection they become the initiator. This situation makes it easier to debug VPN tunnels because then you have the remote information and all of your local information. by initiate the connection, Testing

you will not see the other end’s information.

13. If possible go to the web-based manager on your FortiGate unit, go to the VPN monitor and try to bring the tunnel up.
14. Stop the debug output:

diag debug disable

15. Go back through the output to determine what proposal information the initiator is using, and how it is different from your VPN P1 proposal settings.

Things to look for in the debug output of attempted VPN connections are shown below.

Important terms to look for in VPN debug output

Hub-and-spoke configurations

This section describes how to set up hub-and-spoke IPsec VPNs. The following topics are included in this section:

Configuration overview

Configure the hub

Configure the spokes

Dynamic spokes configuration example

Configuration overview

In a hub-and-spoke configuration, VPN connections radiate from a central FortiGate unit (the hub) to a number of remote peers (the spokes). Traffic can pass between private networks behind the hub and private networks behind the remote peers. Traffic can also pass between remote peer private networks through the hub.

Example hub-and-spoke configuration

The actual implementation varies in complexity depending on:

Configuration overview

• Whether the spokes are statically or dynamically addressed
• The addressing scheme of the protected subnets
• How peers are authenticated

This guide discusses the issues involved in configuring a hub-and-spoke VPN and provides some basic configuration examples.

Hub-and-spoke infrastructure requirements

• The FortiGate hub must be operating in NAT mode and have a static public IP address.
• Spokes may have static IP addresses, dynamic IP addresses (see FortiGate dialup-client configurations on page 1), or static domain names and dynamic IP addresses (see Dynamic DNS configuration on page 1).

Spoke gateway addressing

The public IP address of the spoke is the VPN remote gateway as seen from the hub. Statically addressed spokes each require a separate VPN Phase 1 configuration on the hub. When there are many spokes, this becomes rather cumbersome.

Using dynamic addressing for spokes simplifies the VPN configuration because then the hub requires only a single Phase 1 configuration with “dialup user” as the remote gateway. You can use this configuration even if the remote peers have static IP addresses. A remote peer can establish a VPN connection regardless of its IP address if its traffic selectors match and it can authenticate to the hub. See Configuration overview on page 100 for an example of this configuration.

Protected networks addressing

The addresses of the protected networks are needed to configure destination selectors and sometimes for security policies and static routes. The larger the number of spokes, the more addresses there are to manage. You can

• Assign spoke subnets as part of a larger subnet, usually on a new network or
• Create address groups that contain all of the needed addresses

Using aggregated subnets

If you are creating a new network, where subnet IP addresses are not already assigned, you can simplify the VPN configuration by assigning spoke subnets that are part of a large subnet.

Aggregated subnets

All spokes use the large subnet address, 10.1.0.0/16 for example, as:

• The IPsec destination selector
• The destination of the security policy from the private subnet to the VPN (required for policy-based VPN, optional for route-based VPN)
• The destination of the static route to the VPN (route-based)

Each spoke uses the address of its own protected subnet as the IPsec source selector and as the source address in its VPN security policy. The remote gateway is the public IP address of the hub FortiGate unit.

Using an address group

If you want to create a hub-and-spoke VPN between existing private networks, the subnet addressing usually does not fit the aggregated subnet model discussed earlier. All of the spokes and the hub will need to include the addresses of all the protected networks in their configuration.

On FortiGate units, you can define a named firewall address for each of the remote protected networks and add these addresses to a firewall address group. For a policy-based VPN, you can then use this address group as the destination of the VPN security policy.

For a route-based VPN, the destination of the VPN security policy can be set to All. You need to specify appropriate routes for each of the remote subnets.

Authentication

Authentication is by a common pre-shared key or by certificates. For simplicity, the examples in this chapter assume that all spokes use the same pre-shared key.

Configure the hub

At the FortiGate unit that acts as the hub, you need to:

hub

• Configure the VPN to each spoke
• Configure communication between spokes

You configure communication between spokes differently for a policy-based VPN than for a route-based VPN. For a policy-based VPN, you configure a VPN concentrator. For a route-based VPN, you must either define security policies or group the IPsec interfaces into a zone.

Define the hub-spoke VPNs

Perform these steps at the FortiGate unit that will act as the hub. Although this procedure assumes that the spokes are all FortiGate units, a spoke could also be VPN client software, such as FortiClient Endpoint Security.

Configuring the VPN hub

1. At the hub, define the Phase 1 configuration for each spoke. See Phase 1 parameters on page 52. Enter these settings in particular:

2. Define the Phase 2 parameters needed to create a VPN tunnel with each spoke. See Phase 2 parameters on page
3. 72. Enter these settings in particular:

IPsec VPN in ADVPN hub-and-spoke

IPsec VPN traffic is allowed through a tunnel between an ADVPN hub-and-spoke.

CLI Syntax:

config vpn ipsec phase1-interface edit “int-fgtb” … set auto-discovery-sender [enable | disable] set auto-discovery-receiver [enable | disable] set auto-discovery-forwarder [enable | disable] …

next

end

config vpn ipsec phase2-interface edit “int-fgtb” …

set auto-discovery-sender phase1 [enable | disable] …

next

end

Define the hub-spoke security policies

1. Define a name for the address of the private network behind the hub. For more information, see Defining policy addresses on page 1.
2. Define names for the addresses or address ranges of the private networks behind the spokes. For more information, see Defining policy addresses on page 1.
3. Define the VPN concentrator. See To define the VPN concentrator on page 105.
4. Define security policies to permit communication between the hub and the spokes. For more information, see Defining VPN security policies on page 1.

Route-based VPN security policies

Define ACCEPT security policies to permit communications between the hub and the spoke. You need one policy for each direction.

Adding policies

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.
3. Enter these settings in particular:

hub

Policy-based VPN security policy

Define an IPsec security policy to permit communications between the hub and the spoke.

Adding policies

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

In the policy list, arrange the policies in the following order:

l IPsec policies that control traffic between the hub and the spokes first  l The default security policy last

Configuring communication between spokes (policy-based VPN)

For a policy-based hub-and-spoke VPN, you define a concentrator to enable communication between the spokes.

To define the VPN concentrator

1. At the hub, go to VPN > IPsec Concentrator and select Create New.
2. In the Concentrator Name field, type a name to identify the concentrator.
3. From the Available Tunnels list, select a VPN tunnel and then select the right-pointing arrow.
4. Repeat Step 3 until all of the tunnels associated with the spokes are included in the concentrator.
5. Select OK.

Configuring communication between spokes (route-based VPN)

For a route-based hub-and-spoke VPN, there are several ways you can enable communication between the spokes:

• Put all of the IPsec interfaces into a zone and enable intra-zone traffic. This eliminates the need for any security policy for the VPN, but you cannot apply UTM features to scan the traffic for security threats.
• Put all of the IPsec interfaces into a zone and create a single zone-to-zone security policy
• Create a security policy for each pair of spokes that are allowed to communicate with each other. The number of policies required increases rapidly as the number of spokes increases.

Using a zone as a concentrator

A simple way to provide communication among all of the spokes is to create a zone and allow intra-zone communication. You cannot apply UTM features using this method.

1. Go to Network > Interfaces.
2. Select the down-arrow on the Create New button and select Zone.
3. In the Zone Name field, enter a name, such as Our_VPN_zone.
4. Clear Block intra-zone traffic.
5. In the Interface Members list, select the IPsec interfaces that are part of your VPN.
6. Select OK.

Using a zone with a policy as a concentrator

If you put all of the hub IPsec interfaces involved in the VPN into a zone, you can enable communication among all of the spokes and apply UTM features with just one security policy.

Creating a zone for the VPN

1. Go to Network > Interfaces.
2. Select the down-arrow on the Create New button and select Zone.
3. In the Zone Name field, enter a name, such as Our_VPN_zone.
4. Select Block intra-zone traffic.
5. In the Interface Members list, select the IPsec interfaces that are part of your VPN.
6. Select OK.

Creating a security policy for the zone

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.
3. Enter the settings: and select OK.

spokes

Using security policies as a concentrator

To enable communication between two spokes, you need to define an ACCEPT security policy for them. To allow either spoke to initiate communication, you must create a policy for each direction. This procedure describes a security policy for communication from Spoke 1 to Spoke 2. Others are similar.

1. Define names for the addresses or address ranges of the private networks behind each spoke. For more information, see Defining policy addresses on page 1.
2. Go to Policy & Objects > IPv4 Policy and select Create New.
3. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.
4. Enter the settings and select OK.

Configure the spokes

Although this procedure assumes that the spokes are all FortiGate units, a spoke could also be VPN client software, such as FortiClient Endpoint Security.

Perform these steps at each FortiGate unit that will act as a spoke.

Creating the Phase 1 and phase_2 configurations

1. At the spoke, define the Phase 1 parameters that the spoke will use to establish a secure connection with the hub. See Phase 1 parameters on page 52. Enter these settings:

Configure the spokes

2. Create the Phase 2 tunnel definition. See Phase 2 parameters on page 72. Select the set of Phase 1 parameters that you defined for the hub. You can select the name of the hub from the Static IP Address part of the list.

Configuring security policies for hub-to-spoke communication

1. Create an address for this spoke. See Defining policy addresses on page 1. Enter the IP address and netmask of the private network behind the spoke.
2. Create an address to represent the hub. See Defining policy addresses on page 1. Enter the IP address and netmask of the private network behind the hub.
3. Define the security policy to enable communication with the hub.

Route-based VPN security policy

Define two security policies to permit communications to and from the hub.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.
3. Enter these settings:

Policy-based VPN security policy

Define an IPsec security policy to permit communications with the hub. See Defining VPN security policies on page 1.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

spokes

Configuring security policies for spoke-to-spoke communication

Each spoke requires security policies to enable communication with the other spokes. Instead of creating separate security policies for each spoke, you can create an address group that contains the addresses of the networks behind the other spokes. The security policy then applies to all of the spokes in the group.

1. Define destination addresses to represent the networks behind each of the other spokes. Add these addresses to an address group.
2. Define the security policy to enable communication between this spoke and the spokes in the address group you created.

Policy-based VPN security policy

Define an IPsec security policy to permit communications with the other spokes. See Defining VPN security policies on page 1. Enter these settings in particular:

Route-based VPN security policy

Define two security policies to permit communications to and from the other spokes.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address. Enter these settings in particular:

4. Select Create New, leave the Policy Type as Firewall and leave the Policy Subtype as Address, and enter these settings:

Policy-based VPN security policy

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter the following:

Place this policy or policies in the policy list above any other policies having similar source and destination addresses.

Dynamic spokes configuration example

This example demonstrates how to set up a basic route-based hub-and-spoke IPsec VPN that uses preshared keys to authenticate VPN peers.

Example hub-and-spoke configuration

In the example configuration, the protected networks 10.1.0.0/24, 10.1.1.0/24 and 10.1.2.0/24 are all part of the larger subnet 10.1.0.0/16. The steps for setting up the example hub-and-spoke configuration create a VPN among Site 1, Site 2, and the HR Network.

The spokes are dialup. Their addresses are not part of the configuration on the hub, so only one spoke definition is required no matter the number of spokes. For simplicity, only two spokes are shown.

In an ADVPN topology, any two pair of peers can create a shortcut, as long as one of the devices is not behind NAT.

The on-the-wire format of the ADVPN messages  use TLV encoding.  Because of this, this feature is not compatible with any previous ADVPN builds.

Configure the hub (FortiGate_1)

The Phase 1 configuration defines the parameters that FortiGate_1 will use to authenticate spokes and establish secure connections.

For the purposes of this example, one preshared key will be used to authenticate all of the spokes. Each key must contain at least 6 printable characters and best practices dictates that it only be known by network administrators. For optimum protection against currently known attacks, each key must consist of a minimum of 16 randomly chosen alphanumeric characters.

Define the IPsec configuration

1. At FortiGate_1, go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit the Phase 1 Proposal (if it is not available, you may need to click the Convert to Custom Tunnel button).

Define the Phase 1 parameters that the hub will use to establish a secure connection to the spokes.

The basic Phase 2 settings associate IPsec Phase 2 parameters with the Phase 1 configuration and specify the remote end points of the VPN tunnels.

3. Open the Phase 2 Selectors panel (if it is not available, you may need to click the Convert to Custom Tunnel button).
4. Enter the following information, and select OK:

Define the security policies

security policies control all IP traffic passing between a source address and a destination address. For a routebased VPN, the policies are simpler than for a policy-based VPN. Instead of an IPSEC policy, you use an ACCEPT policy with the virtual IPsec interface as the external interface.

Before you define security policies, you must first define firewall addresses to use in those policies. You need addresses for:

• The HR network behind FortiGate_1
• The aggregate subnet address for the protected networks

Defining the IP address of the HR network behind FortiGate_1

1. Go to Policy & Objects > Addresses.
2. Select Create New, enter the following information, and select OK:

Specifying the IP address the aggregate protected subnet

1. Go to Policy & Objects > Addresses.
2. Select Create New, enter the following information, and select OK:

Defining the security policy for traffic from the hub to the spokes  1. Go to Policy & Objects > IPv4 Policy and select Create New,

2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address. 3. Enter the following information, and select OK:

Place the policy in the policy list above any other policies having similar source and destination addresses.

Configure communication between spokes

Spokes communicate with each other through the hub. You need to configure the hub to allow this

communication. An easy way to do this is to create a zone containing the virtual IPsec interfaces even if there is only one, and create a zone-to-zone security policy.

1. Go to Network > Interfaces.
2. Select the down-arrow on the Create New button and select Zone.
3. In the Zone Name field, enter a name, such as Our_VPN_zone.
4. Select Block intra-zone traffic.

You could enable intra-zone traffic and then you would not need to create a security policy. But, you would not be able to apply UTM features.

5. In Interface Members, select the virtual IPsec interface, toSpokes.
6. Select OK.

Creating a security policy for the zone

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.
3. Enter these settings:

4. Select OK.

Configure the spokes

In this example, all spokes have nearly identical configuration, requiring the following:

• Phase 1 authentication parameters to initiate a connection with the hub.
• Phase 2 tunnel creation parameters to establish a VPN tunnel with the hub.
• A source address that represents the network behind the spoke. This is the only part of the configuration that is different for each spoke.
• A destination address that represents the aggregate protected network.
• A security policy to ena.ble communications between the spoke and the aggregate protected network Define the IPsec configuration

At each spoke, create the following configuration.

1. At the spoke, go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit the Phase 1 Proposal (if it is not available, you may need to click the Convert to Custom Tunnel button). Enter the following information:

1. Open the Phase 2 Selectors panel (if it is not available, you may need to click the Convert to Custom Tunnel button).
2. Enter the following information and select OK:

Define the security policies

You need to define firewall addresses for the spokes and the aggregate protected network and then create a security policy to enable communication between them.

Defining the IP address of the network behind the spoke

1. Go to Policy & Objects > Addresses.
2. Select Create New and enter the following information:

Specifying the IP address of the aggregate protected network

1. Go to Policy & Objects > Addresses.
2. Select Create New and enter the following information:

Defining the security policy

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.
3. Enter the following information:

4. Select Create New.
5. Leave the Policy Type as Firewall and leave the Policy Subtype as Address. Enter the following information, and select OK:

Place these policies in the policy list above any other policies having similar source and destination addresses.

Dynamic DNS configuration

This section describes how to configure a site-to-site VPN, in which one FortiGate unit has a static IP address and the other FortiGate unit has a domain name and a dynamic IP address.

The following topics are included in this section:

Dynamic DNS over VPN concepts

DDNS topology

Configuration overview

Dynamic DNS over VPN concepts

A typical computer has a static IP address and one or more DNS servers to resolve fully qualified domain names (FQDN) into IP addresses. A domain name assigned to this computer is resolved by any DNS server having an entry for the domain name and its static IP address. The IP address never changes or changes only rarely so the DNS server can reliably say it has the correct address for that domain all the time.

Dynamic DNS (DDNS)

It is different when a computer has a dynamic IP address, such as an IP address assigned dynamically by a DHCP server, and a domain name. Computers that want to contact this computer do not know what its current IP address is. To solve this problem there are dynamic DNS (DDNS) servers. These are public servers that store a DNS entry for your computer that includes its current IP address and associated domain name. These entries are kept up to date by your computer sending its current IP address to the DDNS  server to ensure its entry is always up to date. When other computers want to contact your domain, their DNS gets your IP address from your DDNS server. To use DDNS servers, you must subscribe to them and usually pay for their services.

When configuring DDNS on your FortiGate unit, go to Network > DNS and enable Enable FortiGuard DDNS. Then select the interface with the dynamic connection, which DDNS server you have an account with, your domain name, and account information. If your DDNS server is not on the list, there is a generic option where you can provide your DDNS server information.

Routing

When an interface has some form of changing IP address (DDNS, PPPoE, or DHCP assigned address), routing needs special attention. The standard static route cannot handle the changing IP address. The solution is to use the dynamic-gateway command in the CLI. Say for example you already have four static routes, and you have a PPPoE connection over the wan2 interface and you want to use that as your default route.

The route is configured on the dynamic address VPN peer trying to access the static address FortiGate unit.

Configuring dynamic gateway routing – CLI

config router static edit 5 set dst 0.0.0.0 0.0.0.0 set dynamic-gateway enable set device wan2

Dynamic DNS over VPN concepts

next

end

For more information on DDNS, see the System Administration handbook chapter.

DDNS over VPN

IPsec VPN expects an IP address for each end of the VPN tunnel. All configuration and communication with that tunnel depends on the IP addresses as reference points. However, when the interface the tunnel is on has DDNS enabled there is no set IP address. The remote end of the VPN tunnel now needs another way to reference your end of the VPN tunnel. This is accomplished using Local ID.

A FortiGate unit that has a domain name and a dynamic IP address can initiate VPN connections anytime. The remote peer can reply to the local FortiGate unit using the source IP address that was sent in the packet header because it is current. Without doing a DNS lookup first, the remote peer runs the risk of the dynamic IP changing before it attempts to connect. To avoid this, the remote peer must perform a DNS lookup for the domain name of to be sure of the dynamic IP address before initiating the connection.

Remote Gateway

When configuring the Phase 1 entry for a VPN tunnel, the Remote Gateway determines the addressing method the remote end of the tunnel uses as one of Static IP Address, Dialup User, or Dynamic DNS. There are different fields for each option.

When you select the Dynamic DNS VPN type there is a related field called Dynamic DNS. The Dynamic DNS field is asking for the FQDN of the remote end of the tunnel. It uses this information to look up the IP address of the remote end of the tunnel through the DDNS server associated with that domain name.

Local ID (peer ID)

The Local ID or peer ID can be used to uniquely identify one end of a VPN tunnel. This enables a more secure connection. Also if you have multiple VPN tunnels negotiating, this ensures the proper remote and local ends connect. When you configure it on your end, it is your Local ID. When the remote end connects to you, they see it as your peer ID.

If you are debugging a VPN connection, the Local ID is part of the VPN negotiations. You can use it to help troubleshoot connection problems.

Configuring your Local ID

1. Go to VPN > IPsec Wizard and create the new custom tunnel or go to VPN > IPsec Tunnels and edit an existing tunnel.
2. Edit the Phase 1 Proposal (if it is not available, you may need to click the Convert To Custom Tunnel button).
3. In the Phase 1 Proposal section, enter your Local ID.
4. Select OK.

The default configuration is to accept all local IDs (peer IDs). If you have Local ID set, the remote end of the tunnel must be configured to accept your local ID.

DDNS topology

Accepting a specific Peer ID

1. Go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit Authentication (if it is not available, you may need to click the Convert To Custom Tunnel button).
3. Set Mode to Aggressive.
4. For Peer Options, select This peer ID. This option becomes visible only when Aggressive mode is selected.
5. In the Peer ID field, enter the string the other end of the tunnel used for its local ID.
6. Configure the rest of the Phase 1 entry as required.
7. Select OK.

Route-based or policy-based VPN

VPN over dynamic DNS can be configured with either route-based or policy-based VPN settings. Both are valid, but have differences in configuration. Choose the best method based on your requirements. For more information on route-based and policy-based, see IPsec VPN overview on page 33.

Route-based VPN configuration requires two security policies to be configured (one for each direction of traffic) to permit traffic over the VPN virtual interface, and you must also add a static route entry for that VPN interface or the VPN traffic will not reach its destination. See Dynamic DNS configuration on page 117 and Dynamic DNS configuration on page 117.

Policy-based VPN configuration uses more complex and often more IPsec security policies, but does not require a static route entry. It has the benefit of being able to configure multiple policies for handling multiple protocols in different ways, such as more scanning of less secure protocols or guaranteeing a minimum bandwidth for protocols such as VoIP. See Dynamic DNS configuration on page 117 and Dynamic DNS configuration on page 117.

DDNS topology

In this scenario, two branch offices each have a FortiGate unit and are connected in a gateway-to-gateway VPN configuration. One FortiGate unit has a domain name (example.com) with a dynamic IP address. See branch_ 2 in the figure below.

Whenever the branch_2 unit connects to the Internet (and possibly also at predefined intervals set by the ISP), the ISP may assign a different IP address to the FortiGate unit. The unit has its domain name registered with a dynamic DNS service. The branch_2 unit checks in with the DDNS server on a regular basis, and that server provides the DNS information for the domain name, updating the IP address from time to time. Remote peers have to locate the branch_2 FortiGate unit through a DNS lookup each time to ensure the address they get is current and correct.

Example dynamic DNS configuration

When a remote peer (such as the branch_1 FortiGate unit above) initiates a connection to example.com, the local DNS server looks up and returns the IP address that matches the domain name example.com. The remote peer uses the retrieved IP address to establish a VPN connection with the branch_2 FortiGate unit.

Assumptions

• You have administrator access to both FortiGate units.
• Both FortiGate units have interfaces named wan1 and internal. (If not, you can use the alias feature to assign these labels as “nicknames” to other interfaces to follow this example.)
• Both FortiGate units have the most recent firmware installed, have been configured for their networks, and are currently passing normal network traffic.
• The branch_2 FortiGate unit has its wan1 interface defined as a dynamic DNS interface with the domain name of com.
• A basic gateway-to-gateway configuration is in place (see Gateway-to-gateway configurations on page 1) except one of the FortiGate units has a static domain name and a dynamic IP address instead of a static IP address.
• The FortiGate unit with the domain name is subscribed to one of the supported dynamic DNS services. Contact one of the services to set up an account. For more information and instructions about how to configure the FortiGate unit to push its dynamic IP address to a dynamic DNS server, see the System Administration handbook chapter.

Configuration overview

When a FortiGate unit receives a connection request from a remote VPN peer, it uses IPsec Phase 1 parameters to establish a secure connection and authenticate the VPN peer. Then, if the security policy permits the connection, the FortiGate unit establishes the tunnel using IPsec Phase 2 parameters and applies the security policy. Key management, authentication, and security services are negotiated dynamically through the IKE protocol.

To support these functions, the following general configuration steps must be performed:

• Configure the branch_2 FortiGate unit with the dynamic IP address. This unit uses a Local ID string instead of an IP address to identify itself to the remote peer. See Configuring the dynamically-addressed VPN peer below, which is made up of configuring branch_2’s VPN tunnel settings and security policies.
• Configure the fixed-address VPN peer. To initiate a VPN tunnel with the dynamically-addressed peer, this unit must first retrieve the IP address for the domain from the dynamic DNS service. See Configuring the fixed-address VPN peer, which is made up of configuring branch_1’s VPN tunnel settings and security policies.

Configuring the dynamically-addressed VPN peer

It is assumed that this FortiGate unit (branch_2) has already had its public facing interface, for example the wan1, configured with the proper dynamic DNS configuration.

Configuring branch_2, the dynamic address side

Define the Phase 1 parameters needed to establish a secure connection with the remote peer. See Phase 1 parameters on page 52. During this procedure you need to choose if you will be using route-based or policy-based VPNs.

1. Go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit Network (full configuration options are only available once you click the Convert To Custom Tunnel button).
3. Enter the following information:

4. Edit Authentication and complete the following:

5. Edit Phase 1 Proposal and complete the following:

6. Open the Phase 2 Selectors

Define the Phase 2 parameters needed to create a VPN tunnel with the remote peer. For details on Phase 2, see Phase 2 parameters on page 72.

7. Enter the following information and select OK.

Define security policies to permit communications between the private networks through the VPN tunnel. Routebased and policy-based VPNs require different security policies. For detailed information about creating security policies, see Defining VPN security policies on page 1.

After defining the two address ranges, select one of Creating branch_2 route-ased security policies on page 123 or Creating branch_2 policy-based security policies on page 125 to configure the appropriate VPN policies.

Define VPN connection names for the address ranges of the private networks. These addresses are used in the security policies that permit communication between the networks. For more information, see Defining VPN security policies on page 1.

Define an address name for the IP address and netmask of the private network behind the local FortiGate unit.

1. Go to Policy & Objects > Addresses.
2. Select Create New.
3. Enter the following information, and select OK.

Define an address name for the IP address and netmask of the private network behind the remote peer.

4. Select Create New.
5. Enter the following information, and select OK.

Creating branch_2 route-ased security policies

Define ACCEPT security policies to permit communication between the branch_2 and branch_1 private networks. Once the route-based policy is configured a routing entry must be configured to route traffic over the VPN interface.

Define a policy to permit the branch_2 local FortiGate unit to initiate a VPN session with the branch_1 VPN peer.

1. Go to Policy & Objects > IPv4 Policy and select Create New. 2. Enter the following information, and select OK.

Define a policy to permit the branch_1 remote VPN peer to initiate VPN sessions.

3. Select Create New.
4. Enter the following information, and select OK.

5. Optionally configure any other security policy settings you require such as UTM or traffic shaping for this policy.
6. Place these policies in the policy list above any other policies having similar source and destination addresses. This will ensure VPN traffic is matched against the VPN policies before any other policies.

Creating routing entry for VPN interface – CLI

config router static edit 5 set dst 0.0.0.0 0.0.0.0

set dynamic-dateway enable set device wan1

next

end

This routing entry must be added in the CLI because the dynamic-gateway option is not available in the webbased manager.

Creating branch_2 policy-based security policies

Define an IPsec policy to permit VPN sessions between the private networks. Define an IPsec policy to permit the VPN sessions between the local branch_2 unit and the remote branch_1 unit.

1. Go to Policy & Objects > IPv4 Policy and select Create New. 2. Enter the following information, and select OK.

3. Optionally configure any other security policy settings you require such as UTM or traffic shaping for this policy.
4. Place these policies in the policy list above any other policies having similar source and destination addresses. This will ensure VPN traffic is matched against the VPN policies before any other policies.

Configuring the fixed-address VPN peer

The fixed-address VPN peer, branch_1, needs to retrieve the IP address from the dynamic DNS service to initiate communication with the dynamically-addressed peer, branch_2. It also depends on the peer ID (local ID) to initiate the VPN tunnel with branch_2.

Define the Phase 1 parameters needed to establish a secure connection with the remote peer. For more information, see Phase 1 parameters on page 52.

1. Go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit Network (if it is not available, you may need to click the Convert to Custom Tunnel button). Enter the following information and select OK.

4. Edit Authentication, enter the following information and select OK.

5. Define the Phase 2 parameters needed to create a VPN tunnel with the remote peer. See Phase 2 parameters on page 72. Enter these settings in particular:

The branch_1 FortiGate unit has a fixed IP address and will be connecting to the branch_2 FortiGate unit that has a dynamic IP address and a domain name of example.com. Remember if you are using route-based security policies that you must add a route for the VPN traffic.

Defining address ranges for branch_1 security policies

As with branch_2 previously, branch_1 needs address ranges defined as well. See Defining policy addresses on page 1.

1. Go to Policy & Objects > Addresses and select Create New > Address.
2. Enter the following information, and select OK.

3. Define an address name for the IP address and netmask of the private network behind the remote peer. Create another address. Enter the following information, and select OK.

Creating branch_1 route-based security policies

Define an ACCEPT security policy to permit communications between the source and destination addresses. See Defining VPN security policies on page 1.

1. Go to Policy & Objects > IPv4 Policy and select Create New. 2. Enter the following information, and select OK.

To permit the remote client to initiate communication, you need to define a security policy for communication in that direction.

3. Select Create New.
4. Enter the following information, and select OK.

Creating branch_1 policy-based security policies

A policy-based security policy allows you the flexibility to allow inbound or outbound traffic or both through this single policy.

This policy-based IPsec VPN security policy allows both inbound and outbound traffic

1. Go to Policy & Objects > IPv4 Policy and select Create New. 2. Enter the following information, and select OK.

3. Place this security policy in the policy list above any other policies having similar source and destination addresses.

Results

Once both ends are configured, you can test the VPN tunnel.

To test the VPN initiated by branch_2

1. On branch_2, go to Monitor > IPsec Monitor.

All IPsec VPN tunnels will be listed on this page, no matter if they are connected or disconnected.

2. Select the tunnel listed for branch_2, and select the status column for that entry.

The status will say Bring Up and remote port, incoming and outgoing data will all be zero. This indicates an inactive tunnel. When you right-click and select Bring Up, the FortiGate will try to set up a VPN session over this tunnel. If it is successful, Bring Up will change to Active, and the arrow icon will change to a green up arrow icon.

3. If this does not create a VPN tunnel with increasing values for incoming and outgoing data, you need to start troubleshooting:

To test the VPN initiated by branch_1

1. On branch_1, go to Monitor > IPsec Monitor.
2. Select the tunnel listed for branch_1, and select the status column.

The difference between branch_2 and branch_1 at this point is that the tunnel entry for branch-1 will not have a remote gateway IP address. It will be resolved when the VPN tunnel is started.

3. If this does not create a VPN tunnel with increasing values for incoming and outgoing data, you need to start troubleshooting.

Some troubleshooting ideas include:

• If there was no entry for the tunnel on the monitor page, check the Auto Key (IKE) page to verify the Phase 1 and Phase 2 entries exist.
• Check the security policy or policies, and ensure there is an outgoing policy as a minimum.
• Check that you entered a local ID in the Phase 1 configuration, and that branch_1 has the same local ID. l Ensure the local DNS server has an up-to-date DNS entry for exmaple.com.

For more information, see Troubleshooting on page 1.

FortiClient dialup-client configuration

The FortiClient Endpoint Security application is an IPsec VPN client with antivirus, antispam and firewall capabilities. This section explains how to configure dialup VPN connections between a FortiGate unit and one or more FortiClient Endpoint Security applications.

FortiClient users are usually mobile or remote users who need to connect to a private network behind a FortiGate unit. For example, the users might be employees who connect to the office network while traveling or from their homes.

For greatest ease of use, the FortiClient application can download the VPN settings from the FortiGate unit to configure itself automatically.

The following topics are included in this section:

Configuration overview

Configuration overview

Dialup users typically obtain dynamic IP addresses from an ISP through Dynamic Host Configuration Protocol (DHCP) or Point-to-Point Protocol over Ethernet (PPPoE). Then, the FortiClient Endpoint Security application initiates a connection to a FortiGate dialup server.

By default the FortiClient dialup client has the same IP address as the host PC on which it runs. If the host connects directly to the Internet, this is a public IP address. If the host is behind a NAT device, such as a router, the IP address is a private IP address. The NAT device must be NAT traversal (NAT-T) compatible to pass encrypted packets (see Phase 1 parameters on page 52). The FortiClient application also can be configured to use a virtual IP address (VIP). For the duration of the connection, the FortiClient application and the FortiGate unit both use the VIP address as the IP address of the FortiClient dialup client.

The FortiClient application sends its encrypted packets to the VPN remote gateway, which is usually the public interface of the FortiGate unit. It also uses this interface to download VPN settings from the FortiGate unit. See Automatic configuration of FortiClient dialup clients on page 131.

Example FortiClient dialup-client configuration

Peer identification

The FortiClient application can establish an IPsec tunnel with a FortiGate unit configured to act as a dialup server. When the FortiGate unit acts as a dialup server, it does not identify the client using the Phase 1 remote gateway address. The IPsec tunnel is established if authentication is successful and the IPsec security policy associated with the tunnel permits access. If configured, the FortiGate unit could also require FortiClient registration, that is, the remote user would be required to have FortiClient installed before connection is completed.

Automatic configuration of FortiClient dialup clients

The FortiClient application can obtain its VPN settings from the FortiGate VPN server. FortiClient users need to know only the FortiGate VPN server IP address and their username and password on the FortiGate unit.

The FortiGate unit listens for VPN policy requests from clients on TCP port 8900. When the dialup client connects:

• The client initiates a Secure Sockets Layer (SSL) connection to the FortiGate unit.
• The FortiGate unit requests a user name and password from the FortiClient user. Using these credentials, it authenticates the client and determines which VPN policy applies to the client.
• Provided that authentication is successful, the FortiGate unit downloads a VPN policy to the client over the SSL connection. The information includes IPsec Phase 1 and Phase 2 settings, and the IP addresses of the private networks that the client is authorized to access.
• The client uses the VPN policy settings to establish an IPsec Phase 1 connection and Phase 2 tunnel with the FortiGate unit.

FortiClient-to-FortiGate VPN configuration steps

Configuring dialup client capability for FortiClient dialup clients involves the following general configuration steps:

1. If you will be using VIP addresses to identify dialup clients, determine which VIP addresses to use. As a precaution, consider using VIP addresses that are not commonly used.
2. Configure the FortiGate unit to act as a dialup server. See Configure the FortiGate unit on page 1.
3. If the dialup clients will be configured to obtain VIP addresses through DHCP over IPsec, configure the FortiGate unit to act as a DHCP server or to relay DHCP requests to an external DHCP server.
4. Configure the dialup clients. See Configure the FortiClient Endpoint Security application on page 1.

Using virtual IP addresses

When the FortiClient host PC is located behind a NAT device, unintended IP address overlap issues may arise between the private networks at the two ends of the tunnel. For example, the client’s host might receive a private IP address from a DHCP server on its network that by co-incidence is the same as a private IP address on the network behind the FortiGate unit. A conflict will occur in the host’s routing table and the FortiClient Endpoint Security application will be unable to send traffic through the tunnel. Configuring virtual IP (VIP) addresses for FortiClient applications prevents this problem.

Using VIPs ensures that client IP addresses are in a predictable range. You can then define security policies that allow access only to that source address range. If you do not use VIPs, the security policies must allow all source addresses because you cannot predict the IP address for a remote mobile user.

The FortiClient application must not have the same IP address as any host on the private network behind the FortiGate unit or any other connected FortiClient application. You can ensure this by reserving a range of IP addresses on the private network for FortiClient users. Or, you can assign FortiClient VIPs from an uncommonly used subnet such as 10.254.254.0/24 or 192.168.254.0/24.

You can reserve a VIP address for a particular client according to its device MAC address and type of connection. The DHCP server then always assigns the reserved VIP address to the client. For more information about this feature, see the “dhcp reserved-address” section in the “system” chapter of the FortiGate CLI Reference.

On the host computer, you can find out the VIP address that the FortiClient Endpoint Security application is using. For example, in Windows command prompt, type

ipconfig /all

On Linux or Mac OS X, type ifconfig in a terminal window. The output will also show the IP address that has been assigned to the host Network Interface Card (NIC).

It is best to assign VIPs using DHCP over IPsec. The FortiGate dialup server can act as a DHCP server or relay requests to an external DHCP server. You can also configure VIPs manually on FortiClient applications, but it is more difficult to ensure that all clients use unique addresses.

If you assign a VIP on the private network behind the FortiGate unit and enable DHCPIPsec (a Phase 2 advanced option), the FortiGate unit acts as a proxy on the local private network for the FortiClient dialup client. Whenever a host on the network behind the dialup server issues an ARP request for the device MAC address of the FortiClient host, the FortiGate unit answers the ARP request on behalf of the FortiClient host and forwards the associated traffic to the FortiClient host through the tunnel. For more information, see Phase 2 parameters on page 72.

FortiGate units fully support RFC 3456. The FortiGate DHCP over IPsec feature can be enabled to allocate VIP addresses to FortiClient dialup clients using a FortiGate DHCP server.

The figure below shows an example of a FortiClient-to-FortiGate VPN where the FortiClient application is assigned a VIP on an uncommonly used subnet. The diagram also shows that while the destination for the information in the encrypted packets is the private network behind the FortiGate unit, the destination of the IPsec packets themselves is the public interface of the FortiGate unit that acts as the end of the VPN tunnel.

IP address assignments in a FortiClient dialup-client configuration

Assigning VIPs by RADIUS user group

If you use XAuth authentication, you can assign users the virtual IP address stored in the Framed-IP-Address field of their record on the RADIUS server. (See RFC 2865 and RFC 2866 for more information about RADIUS fields.) To do this:

• Set the DHCP server IP Assignment Mode to User-group defined method. This is an Advanced setting. See Configuring a DHCP server on a FortiGate interface on page 137.
• Create a new firewall user group and add the RADIUS server to it.
• In your Phase 1 settings, configure the FortiGate unit as an XAuth server and select from User Group the new user group that you created. For more information, see Phase 1 parameters on page 52.
• Configure the FortiClient application to use XAuth. See Configuration overview on page 130.

FortiClient dialup-client infrastructure requirements

• To support policy-based VPNs, the FortiGate dialup server may operate in either NAT mode or transparent mode. NAT mode is required if you want to create a route-based VPN.
• If the FortiClient dialup clients will be configured to obtain VIP addresses through FortiGate DHCP relay, a DHCP server must be available on the network behind the FortiGate unit and the DHCP server must have a direct route to the FortiGate unit.
• If the FortiGate interface to the private network is not the default gateway, the private network behind the FortiGate unit must be configured to route IP traffic destined for dialup clients back (through an appropriate gateway) to the FortiGate interface to the private network. As an alternative, you can configure the IPsec security policy on the FortiGate unit to perform inbound NAT on IP packets. Inbound NAT translates the source addresses of inbound decrypted packets into the IP address of the FortiGate interface to the local private network.

Configuring the FortiGate unit

Configuring the FortiGate unit to establish VPN connections with FortiClient Endpoint Security users involves the following steps:

• Configure the VPN settings
• If the dialup clients use automatic configuration, configure the FortiGate unit as a VPN policy server
• If the dialup clients obtain VIP addresses by DHCP over IPsec, configure an IPsec DHCP server or relay

The procedures in this section cover basic setup of policy-based and route-based VPNs compatible with FortiClient Endpoint Security. A route-based VPN is simpler to configure.

To configure FortiGate unit VPN settings to support FortiClient users, you need to:

• Configure the FortiGate Phase 1 VPN settings
• Configure the FortiGate Phase 2 VPN settings
• Add the security policy

On the local FortiGate unit, define the Phase 1 configuration needed to establish a secure connection with the FortiClient peer. See Phase 1 parameters on page 52.

1. Go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit Network (full configuration options are only available once you click the Convert To Custom Tunnel button).
3. Enter these settings in particular:

4. Edit Authentication and enter the following information:

5. Define the Phase 2 parameters needed to create a VPN tunnel with the FortiClient peer. See Phase 2 parameters on page 72. Enter these settings in particular:

6. Define names for the addresses or address ranges of the private networks that the VPN links. These addresses are used in the security policies that permit communication between the networks. For more information, see Defining policy addresses on page 1.

Enter these settings in particular:

• Define an address name for the individual address or the subnet address that the dialup users access through the VPN.
• If FortiClient users are assigned VIP addresses, define an address name for the subnet to which these VIPs belong.

4. Define security policies to permit communication between the private networks through the VPN tunnel. Routebased and policy-based VPNs require different security policies. For detailed information about creating security policies, see Defining VPN security policies on page 1.

If the security policy, which grants the VPN Connection is limited to certain services, DHCP must be included, otherwise the client won’t be able to retrieve a lease from the FortiGate’s (IPsec) DHCP server, because the DHCP Request (coming out of the tunnel) will be blocked.

Route-based VPN security policies

Define an ACCEPT security policy to permit communications between the source and destination addresses.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

If you want to allow hosts on the private network to initiate communications with the FortiClient users after the tunnel is established, you need to define a security policy for communication in that direction.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

Policy-based VPN security policy

Define an IPsec security policy to permit communications between the source and destination addresses.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

Place VPN policies in the policy list above any other policies having similar source and destination addresses.

Configuring the FortiGate unit as a VPN policy server

When a FortiClient application set to automatic configuration connects to the FortiGate unit, the FortiGate unit requests a user name and password. If the user supplies valid credentials, the FortiGate unit downloads the VPN

settings to the FortiClient application.

You must do the following to configure the FortiGate unit to work as a VPN policy server for FortiClient automatic configuration:

1. Create user accounts for FortiClient users.
2. Create a user group for FortiClient users and the user accounts that you created in step 1.
3. Connect to the FortiGate unit CLI and configure VPN policy distribution as follows:

config vpn ipsec forticlient edit <policy_name> set phase2name <tunnel_name> set usergroupname <group_name> set status enable

end

<tunnel_name> must be the Name you specified in the step 2 of Configuration overview on page 130. <group_name> must be the name of the user group your created for FortiClient users.

Configuring DHCP services on a FortiGate interface

If the FortiClient dialup clients are configured to obtain a VIP address using DHCP, configure the FortiGate dialup server to either:

• Relay DHCP requests to a DHCP server behind the FortiGate unit (see Configuring DHCP relay on a FortiGate interface on page 137 below).
• Act as a DHCP server (see Configuring a DHCP server on a FortiGate interface on page 137).

Note that DHCP services are typically configured during the interface creation stage, but you can return to an interface to modify DHCP settings if need be.

Configuring  DHCP relay on a FortiGate interface

1. Go to Network > Interfaces and select the interface that you want to relay DHCP.
2. Enable DHCP Server, and create a new DHCP Address Range and Netmask.
3. Open the .. menu and set Mode to Relay.
4. Enter the DHCP Server IP.
5. Select OK.

Configuring a DHCP server on a FortiGate interface

1. Go to Network > Interfaces and select the interface that you want to act as a DHCP server.
2. Enable DHCP Server, and create a new DHCP Address Range and Netmask.
3. Set Default Gateway to Specify, and enter the IP address of the default gateway that the DHCP server assigns to DHCP clients.
4. Set DNS Server to Same as System DNS. If you want to use a different DNS server for VPN clients, select Specify and enter an IP address in the available field.
5. Open the .. menu and set Mode to Server. 6. Select OK.

137

Configure the FortiClient Endpoint Security application

The following procedure explains how to configure the FortiClient Endpoint Security application to communicate with a remote FortiGate dialup server using the VIP address that you specify manually. These procedures are based on FortiClient 5.4.1.

Configuring FortiClient

This procedure explains how to configure the FortiClient application manually using the default IKE and IPsec settings. For more information, refer to the FortiClient Administration Guide.

1. Go to Remote Access and select the Settings
2. Select Add a new connection, set the new VPN connection to IPsec VPN, and complete following information:

3. Select OK.

Adding XAuth authentication

For information about configuring a FortiGate unit as an XAuth server, see Phase 1 parameters on page 52. The following procedure explains how to configure the FortiClient application.

Note that XAuth is not compatible with IKE version 2.

For more information on configuring XAuth authentication, see the FortiClient Administration Guide.

I am looking for video requests. Time looks like it may be getting more available so I should be able to start pumping out videos again that run through the various tasks you guys are running into issues with.

The main item so far that people have been interested in seeing is a video discussing the integration of FSSO with a basic FortiGate configuration.

This should be relatively straight forward to do. I will work on getting the lab prepped so I can push this for you guys. Until then, I wanted to reach out and see about specifics needs, wants, or nice to haves that would tickle your fancy video wise.

I will be doing some non-instructional videos discussing some of the things I am seeing on Fortinet’s chassis platform as well as some misc other items in the world of IT Security soon as well.

Post in the comments below if you have any video recommendations

FortiGate dialup-client configurations

This section explains how to set up a FortiGate dialup-client IPsec VPN. In a FortiGate dialup-client configuration, a FortiGate unit with a static IP address acts as a dialup server and a FortiGate unit having a dynamic IP address initiates a VPN tunnel with the FortiGate dialup server.

The following topics are included in this section: Configuration overview

Configuration overview

A dialup client can be a FortiGate unit. The FortiGate dialup client typically obtains a dynamic IP address from an ISP through the Dynamic Host Configuration Protocol (DHCP) or Point-to-Point Protocol over Ethernet (PPPoE) before initiating a connection to a FortiGate dialup server.

Example FortiGate dialup-client configuration

In a dialup-client configuration, the FortiGate dialup server does not rely on a Phase 1 remote gateway address to establish an IPsec VPN connection with dialup clients. As long as authentication is successful and the IPsec security policy associated with the tunnel permits access, the tunnel is established.

Several different ways to authenticate dialup clients and restrict access to private networks based on client credentials are available. To authenticate FortiGate dialup clients and help to distinguish them from FortiClient dialup clients when multiple clients will be connecting to the VPN through the same tunnel, best practices dictate that you assign a unique identifier (local ID or peer ID) to each FortiGate dialup client. For more information, see Phase 1 parameters on page 52.

Whenever you add a unique identifier (local ID) to a FortiGate dialup client for identification purposes, you must select Aggressive mode on the FortiGate dialup server and also specify the identifier as a peer ID on the FortiGate dialup server. For more information, see Phase 1 parameters on page 52.

Users behind the FortiGate dialup server cannot initiate the tunnel because the FortiGate dialup client does not have a static IP address. After the tunnel is initiated by users behind the FortiGate dialup client, traffic from the private network behind the FortiGate dialup server can be sent to the private network behind the FortiGate dialup client.

Encrypted packets from the FortiGate dialup client are addressed to the public interface of the dialup server. Encrypted packets from the dialup server are addressed either to the public IP address of the FortiGate dialup client (if the dialup client connects to the Internet directly), or if the FortiGate dialup client is behind a NAT device, encrypted packets from the dialup server are addressed to the public IP address of the NAT device.

If a router with NAT capabilities is in front of the FortiGate dialup client, the router must be NAT-T compatible for encrypted traffic to pass through the NAT device. For more information, see Phase 1 parameters on page 52.

When the FortiGate dialup server decrypts a packet from the FortiGate dialup client, the source address in the IP header may be one of the following values, depending on the configuration of the network at the far end of the tunnel:

• If the FortiGate dialup client connects to the Internet directly, the source address will be the private IP address of a host or server on the network behind the FortiGate dialup client.
• If the FortiGate dialup client is behind a NAT device, the source address will be the public IP address of the NAT device.

In some cases, computers on the private network behind the FortiGate dialup client may (by co-incidence) have IP addresses that are already used by computers on the network behind the FortiGate dialup server. In this type of situation (ambiguous routing), conflicts may occur in one or both of the FortiGate routing tables and traffic destined for the remote network through the tunnel may not be sent.

In many cases, computers on the private network behind the FortiGate dialup client will most likely obtain IP addresses from a local DHCP server behind the FortiGate dialup client. However, unless the local and remote networks use different private network address spaces, unintended ambiguous routing and IP-address overlap issues may arise.

To avoid these issues, you can configure FortiGate DHCP relay on the dialup client instead of using a DHCP server on the network behind the dialup client. The FortiGate dialup client can be configured to relay DHCP requests from the local private network to a DHCP server that resides on the network behind the FortiGate dialup server. You configure the FortiGate dialup client to pass traffic from the local private network to the remote network by enabling FortiGate DHCP relay on the FortiGate dialup client interface that is connected to the local private network.

Afterward, when a computer on the network behind the dialup client broadcasts a DHCP request, the dialup client relays the message through the tunnel to the remote DHCP server. The remote DHCP server responds with a private IP address for the computer. To avoid ambiguous routing and network overlap issues, the IP addresses assigned to computers behind the dialup client cannot match the network address space used by the private network behind the FortiGate dialup server.

Preventing network overlap in a FortiGate dialup-client configuration

When the DHCP server resides on the private network behind the FortiGate dialup server, the IP destination address specified in the IPsec security policy on the FortiGate dialup client must refer to that network.

You must add a static route to the DHCP server FortiGate unit if it is not directly connected to the private network behind the FortiGate dialup server; its IP address does not match the IP address of the private network. Also, the destination address in the IPsec security policy on the FortiGate dialup client must refer to the DHCP server address. The DHCP server must be configured to assign a range of IP addresses different from the DHCP server’s local network, and also different from the private network addresses behind the FortiGate dialup server. See Routing on page 1.

FortiGate dialup-client infrastructure requirements

The requirements are:

• The FortiGate dialup server must have a static public IP address.
• NAT mode is required if you want to create a route-based VPN.
• The FortiGate dialup server may operate in either NAT mode or transparent mode to support a policy-based VPN.
• Computers on the private network behind the FortiGate dialup client can obtain IP addresses either from a DHCP server behind the FortiGate dialup client, or a DHCP server behind the FortiGate dialup server.
• If the DHCP server resides on the network behind the dialup client, the DHCP server must be configured to assign IP addresses that do not match the private network behind the FortiGate dialup server.
• If the DHCP server resides on the network behind the FortiGate dialup server, the DHCP server must be configured to assign IP addresses that do not match the private network behind the FortiGate dialup client.

Configuring the server to accept FortiGate dialup-client connections

The procedures in this section assume that computers on the private network behind the FortiGate dialup client obtain IP addresses from a local DHCP server. The assigned IP addresses do not match the private network behind the FortiGate dialup server.

In situations where IP-address overlap between the local and remote private networks is likely to occur, FortiGate DHCP relay can be configured on the FortiGate dialup client to relay DHCP requests to a DHCP server behind the FortiGate dialup server. For more information, see To configure DHCP relay on a FortiGate interface on page 1.

Configuring dialup client capability for FortiGate dialup clients involves the following general configuration steps:

• Determine which IP addresses to assign to the private network behind the FortiGate dialup client, and add the IP addresses to the DHCP server behind the FortiGate dialup client. Refer to the software supplier’s documentation to configure the DHCP server.
• Configure the FortiGate dialup server. See Configuration overview on page 139.  l Configure the FortiGate dialup client. See Configuration overview  on page 139.

Before you begin, optionally reserve a unique identifier (peer ID) for the FortiGate dialup client. The dialup client will supply this value to the FortiGate dialup server for authentication purposes during the IPsec Phase 1 exchange. In addition, the value will enable you to distinguish FortiGate dialup-client connections from FortiClient dialup-client connections. The same value must be specified on the dialup server and on the dialup client.

At the FortiGate dialup server, define the Phase 1 parameters needed to authenticate the FortiGate dialup client and establish a secure connection. See Phase 1 parameters on page 52.

1. Go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit Network (full configuration options are only available once you click the Convert To Custom Tunnel button).
3. Enter these settings in particular:

4. Edit Authentication and enter the following information:

5. Define the Phase 2 parameters needed to create a VPN tunnel with the FortiGate dialup client. See Phase 2 parameters on page 72. Enter these settings in particular:

6. Define names for the addresses or address ranges of the private networks that the VPN links. See Defining policy addresses on page 1. Enter these settings in particular:

l Define an address name for the server, host, or network behind the FortiGate dialup server.  l Define an address name for the private network behind the FortiGate dialup client.

4. Define the security policies to permit communications between the private networks through the VPN tunnel. Route-based and policy-based VPNs require different security policies. For detailed information about creating security policies, see Defining VPN security policies on page 1.

Route-based VPN security policy

Define an ACCEPT security policy to permit communications between hosts on the private network behind the FortiGate dialup client and the private network behind this FortiGate dialup server. Because communication cannot be initiated in the opposite direction, there is only one policy.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

Policy-based VPN security policy

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

3. To prevent traffic from the local network from initiating the tunnel after the tunnel has been established, you need to disable the outbound VPN traffic in the CLI config firewall policy edit <policy_number> set outbound disable

end

Place the policy in the policy list above any other policies having similar source and destination addresses.

If configuring a route-based policy, configure a default route for VPN traffic on this interface.

Configuring the FortiGate dialup client

At the FortiGate dialup client, define the Phase 1 parameters needed to authenticate the dialup server and establish a secure connection. See Phase 1 parameters on page 52.

1. Go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit Network (full configuration options are only available once you click the Convert To Custom Tunnel button).
3. Enter these settings in particular:

4. Edit Authentication and enter the following information:

5. Edit Phase 1 Proposal and enter the following information:

6. Define the Phase 2 parameters needed to create a VPN tunnel with the dialup server. See Phase 2 parameters on page 72. Enter these settings in particular:

7. Define names for the addresses or address ranges of the private networks that the VPN links. See Defining policy addresses on page 1. Enter these settings in particular:

l Define an address name for the server, host, or network behind the FortiGate dialup server.  l Define an address name for the private network behind the FortiGate dialup client.

4. Define security policies to permit communication between the private networks through the VPN tunnel. Routebased and policy-based VPNs require different security policies. For detailed information about creating security policies, see Defining VPN security policies on page 1.

Route-based VPN security policy

Define an ACCEPT security policy to permit communications between hosts on the private network behind this FortiGate dialup client and the private network behind the FortiGate dialup server. Because communication cannot be initiated in the opposite direction, there is only one policy.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

Policy-based VPN security policy

Define an IPsec security policy to permit communications between the source and destination addresses.

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter these settings in particular:

Place the policy in the policy list above any other policies having similar source and destination addresses.

Supporting IKE Mode Config clients

IKE Mode Config is an alternative to DHCP over IPsec. A FortiGate unit can be configured as either an IKE Mode Config server or client. This chapter contains the following sections:

IKE Mode Config overview

Automatic configuration overview

IKE Mode Config method

IKE Mode Config overview

Dialup VPN clients connect to a FortiGate unit that acts as a VPN server, providing the client the necessary configuration information to establish a VPN tunnel. The configuration information typically includes a virtual IP address, netmask, and DNS server address.

IKE Mode Config is available only for VPNs that are route-based, also known as interface-based. A FortiGate unit can function as either an IKE Configuration Method server or client. IKE Mode Config is configurable only in the CLI.

Automatic configuration overview

VPN configuration for remote clients is simpler if it is automated. Several protocols support automatic configuration:

• The Fortinet FortiClient Endpoint Security application can completely configure a VPN connection with a suitably configured FortiGate unit given only the FortiGate unit’s address. This protocol is exclusive to Fortinet. For more information, see FortiClient dialup-client configurations on page 1.
• DHCP over IPsec can assign an IP address, Domain, DNS and WINS addresses. The user must first configure IPsec parameters such as gateway address, encryption and authentication algorithms.
• IKE Mode Config can configure host IP address, Domain, DNS and WINS addresses. The user must first configure IPsec parameters such as gateway address, encryption and authentication algorithms. Several network equipment vendors support IKE Mode Config, which is described in the ISAKMP Configuration Method document draft-dukesike-mode-cfg-02.txt.

This chapter describes how to configure a FortiGate unit as either an IKE Mode Config server or client.

IKE Mode Config method

IKE Mode Config is configured with the CLI command config vpn ipsec phase1-interface. The mode-cfg variable enables IKE Mode Config. The type field determines whether you are creating an IKE Mode Config server or a client. Setting type to dynamic creates a server configuration, otherwise the configuration is a client.

Creating an IKE Mode Config client

If the FortiGate unit will connect as a dialup client to a remote gateway that supports IKE Mode Config, the relevant vpn ipsec phase1-interface variables are as follows:

For a complete list of available variables, see the CLI Reference.

IKE Mode Config client example – CLI

In this example, the FortiGate unit connects to a VPN gateway with a static IP address that can be reached through Port 1. Only the port, gateway and proposal information needs to be configured. All other configuration information will come from the IKE Mode Config server.

config vpn ipsec phase1-interface edit vpn1 set ip-version 4 set type static set remote-gw <gw_address> set interface port 1

set proposal 3des-sha1 aes128-sha1 set mode-cfg enable set assign-ip enable end

IKE Mode Config method                                                                                   Supporting IKE Mode Config clients

Creating an IKE Mode Config server

If the FortiGate unit will accept connection requests from dialup clients that support IKE Mode Config, the following vpn ipsec phase1-interface settings are required before any other configuration is attempted:

IKE Mode Config server example – CLI

In this example, the FortiGate unit assigns IKE Mode Config clients addresses in the range of 10.11.101.160 through 10.11.101.180. DNS and WINS server addresses are also provided. The public interface of the FortiGate unit is Port 1.

When IKE Mode-Configuration is enabled, multiple server IPs can be defined in IPsec Phase 1.

The ipv4-split-include  variable specifies a firewall address that represents the networks to which the clients will have access. This destination IP address information is sent to the clients.

Only the CLI fields required for IKE Mode Config are shown here. For detailed information about these variables, see the FortiGate CLI Reference.

config vpn ipsec phase1-interface edit “vpn-p1” set type dynamic set interface “wan1” set xauthtype auto set mode aggressive set mode-cfg enable

set proposal 3des-sha1 aes128-sha1 set dpd disable set dhgrp 2

set xauthexpire on-rekey set authusrgrp “FG-Group1” set ipv4-start-ip 10.10.10.10 set ipv4-end-ip 10.10.10.20 set ipv4-dns-server1 1.1.1.1 set ipv4-dns-server2 2.2.2.2 set ipv4-dns-server3 3.3.3.3 set ipv4-wins-server1 4.4.4.4 set ipv4-wins-server2 5.5.5.5 set domain “fgt1c-domain” set banner “fgt111C-banner”

set backup-gateway “100.100.100.1” “host1.com” “host2” set ipv4-split-include OfficeLAN

end

IP address assignment

After you have enabled the basic configuration, you can configure IP address assignment for clients, as well as DNS and WINS server assignment. Usually you will want to assign IP addresses to clients.

The simplest method to assign IP addresses to clients is to assign addresses from a specific range, similar to a DHCP server.

If your clients are authenticated by a RADIUS server, you can obtain the user’s IP address assignment from the Framed-IP-Address attribute. The user must be authenticated using XAuth.

IKE Mode Config can also use a remote DHCP server to assign the client IP addresses. Up to eight addresses can be selected for either IPv4 or IPv6. After the DHCP proxy has been configured, the assign-ip-from command is used to assign IP addresses via DHCP.

Assigning IP addresses from an address range – CLI

If your VPN uses IPv4 addresses,

config vpn ipsec phase1-interface edit vpn1 set mode-cfg-ipversion 4 set assign-ip enable set assign-ip-type ip set assign-ip-from range set ipv4-start-ip <range_start> set ipv4-end-ip <range_end> set ipv4-netmask <netmask>

end

If your VPN uses IPv6 addresses,

config vpn ipsec phase1-interface edit vpn1 set mode-cfg-ipversion 6 set assign-ip enable set assign-ip-type ip set assign-ip-from range set ipv6-start-ip <range_start> set ipv6-end-ip <range_end> end

IKE Mode Config method                                                                                   Supporting IKE Mode Config clients

Assigning IP addresses from a RADIUS server – CLI

The users must be authenticated by a RADIUS server and assigned to the FortiGate user group <grpname>.

Since the IP address will not be static, type is set to dynamic, and mode-cfg is enabled. This is IKE

Configuration Method so that compatible clients can configure themselves with settings that the FortiGate unit provides.

config vpn ipsec phase1-interface edit vpn1 set type dynamic set mode-cfg enable set assign-ip enable set assign-ip-from usrgrp set xauthtype auto set authusrgrp <grpname>

end

Assigning IP address from DHCP – CLI

The DHCP proxy must first be enabled for IKE Mode Config to use DHCP to assign the VPN client IP address(es).

config system settings set dhcp-proxy enable set dhcp-server-ip [ipv4 address] set dhcp6-server-ip [ipv6-address]

(Up to eight server addresses can be configured)

end

config vpn ipsec phase1-interface edit vpn1 set mode-cfg enable set assign-ip-from dhcp

next

end

Assigning IP address from a named firewall address/group – CLI

config vpn ipsec phase1-interface edit <name>vpn1 set type dynamic set assign-ip-from name set ipv4-name <name> set ipv6-name <name>

next

end

Certificate groups

IKE certificate groups consisting of up to four RSA certificates can be used in IKE Phase 1. Since CA and local certificates are global, the IKE daemon loads them once for all VDOMs and indexes them into trees based on subject and public key hash (for CA certificates), or certificate name (for local certicates). Certifcates are linked together based on the issuer, and certificate chains are built by traversing these links. This reduces the need to keep multiple copies of certificates that could exist in multiple chains.

IKE certificate groups can be configured through the CLI.

Configuring the IKE local ID – CLI

config vpn certificate local edit <name>

set ike-localid <string> set ike-localid-type {asnldn | fqdn} end

Internet-browsing configuration

This section explains how to support secure web browsing performed by dialup VPN clients, and/or hosts behind a remote VPN peer. Remote users can access the private network behind the local FortiGate unit and browse the Internet securely. All traffic generated remotely is subject to the security policy that controls traffic on the private network behind the local FortiGate unit.

The following topics are included in this section:

Configuration overview

Routing all remote traffic through the VPN tunnel

Configuration overview

A VPN provides secure access to a private network behind the FortiGate unit. You can also enable VPN clients to access the Internet securely. The FortiGate unit inspects and processes all traffic between the VPN clients and hosts on the Internet according to the Internet browsing policy. This is accomplished even though the same FortiGate interface is used for both encrypted VPN client traffic and unencrypted Internet traffic.

In the figure below, FortiGate_1 enables secure Internet browsing for FortiClient Endpoint Security users such as Dialup_1 and users on the Site_2 network behind FortiGate_2, which could be a VPN peer or a dialup client.

Example Internet-browsing configuration

Internet-browsing configuration                                                                                              Configuration overview

You can adapt any of the following configurations to provide secure Internet browsing:

• A gateway-to-gateway configuration (see Gateway-to-gateway configurations on page 1)
• A FortiClient dialup-client configuration (see FortiClient dialup-client configurations on page 1)
• A FortiGate dialup-client configuration (see FortiGate dialup-client configurations on page 1)

The procedures in this section assume that one of these configurations is in place, and that it is operating properly.

To create an internet-browsing configuration based on an existing gateway-to-gateway configuration, you must edit the gateway-to-gateway configuration as follows:

• On the FortiGate unit that will provide Internet access, create an Internet browsing security policy. See Configuration overview on page 153, below.
• Configure the remote peer or client to route all traffic through the VPN tunnel. You can do this on a FortiGate unit or on a FortiClient Endpoint Security application. See Configuration overview on page 153.

Creating an Internet browsing security policy

On the FortiGate unit that acts as a VPN server and will provide secure access to the Internet, you must create an Internet browsing security policy. This policy differs depending on whether your gateway-to-gateway configuration is policy-based or route-based.

Creating an Internet browsing policy – policy-based VPN

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter the following information and then select OK:

Creating an Internet browsing policy – route-based VPN

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Enter the following information and then select OK:

Routing all remote traffic through the VPN tunnel                                                          Internet-browsing configuration

The VPN clients must be configured to route all Internet traffic through the VPN tunnel.

Routing all remote traffic through the VPN tunnel

To make use of the Internet browsing configuration on the VPN server, the VPN peer or client must route all traffic through the VPN tunnel. Usually, only the traffic destined for the private network behind the FortiGate VPN server is sent through the tunnel.

The remote end of the VPN can be a FortiGate unit that acts as a peer in a gateway-to-gateway configuration, or a FortiClient application that protects an individual client PC.

• To configure a remote peer FortiGate unit for Internet browsing via VPN, see Configuring a FortiGate remote peer to support Internet browsing on page 155.
• To configure a FortiClient Endpoint Security application for Internet browsing via VPN, see Configuring a FortiClient application to support Internet browsing on page 156.

These procedures assume that your VPN connection to the protected private network is working and that you have configured the FortiGate VPN server for Internet browsing as described in Configuration overview  on page 153.

Configuring a FortiGate remote peer to support Internet browsing

The configuration changes to send all traffic through the VPN differ for policy-based and route-based VPNs.

Routing all traffic through a policy-based VPN

1. At the FortiGate dialup client, go to Policy & Objects > IPv4 Policy.
2. Select the IPsec security policy and then select Edit.
3. From the Destination Address list, select all.
4. Select OK.

Packets are routed through the VPN tunnel, not just those destined for the protected private network.

Routing all traffic through a route-based VPN

1. At the FortiGate dialup client, go to Network > Static Routes.
2. Select the default route (destination IP 0.0.0.0) and then select Edit. If there is no default route, select Create New. Enter the following information and select OK:

155

Internet-browsing configuration                                                        Routing all remote traffic through the VPN tunnel

All packets are routed through the VPN tunnel, not just packets destined for the protected private network.

Configuring a FortiClient application to support Internet browsing

By default, the FortiClient application configures the PC so that traffic destined for the remote protected network passes through the VPN tunnel but all other traffic is sent to the default gateway. You need to modify the FortiClient settings so that it configures the PC to route all outbound traffic through the VPN.

Routing all traffic through VPN – FortiClient application

1. At the remote host, start FortiClient.
2. Go to Remote Access.
3. Select the definition that connects FortiClient to the FortiGate dialup server, select the Settings icon, and select Edit the selected connection.
4. In the Edit VPN Connection dialog box, select Advanced Settings.
5. In the Remote Network group, select Add.
6. In the IP and Subnet Mask fields, type 0.0.0/0.0.0.0 and select OK.

The address is added to the Remote Network list. The first destination IP address in the list establishes a VPN tunnel. The second destination address (0.0.0.0/0.0.0.0 in this case) forces all other traffic through the VPN tunnel.

7. Select OK.

Redundant VPN configurations

This section discusses the options for supporting redundant and partially redundant IPsec VPNs, using routebased approaches.

The following topics are included in this section: Configuration overview

Configuration overview

A FortiGate unit with two interfaces connected to the Internet can be configured to support redundant VPNs to the same remote peer. If the primary connection fails, the FortiGate unit can establish a VPN using the other connection.

Redundant tunnels do not support Tunnel Mode or manual keys. You must use Interface Mode.

A fully-redundant configuration requires redundant connections to the Internet on both peers. The figure below shows an example of this. This is useful to create a reliable connection between two FortiGate units with static IP addresses.

When only one peer has redundant connections, the configuration is partially-redundant. For an example of this, see Configuration overview on page 157. This is useful to provide reliable service from a FortiGate unit with static IP addresses that accepts connections from dialup IPsec VPN clients.

In a fully-redundant VPN configuration with two interfaces on each peer, four distinct paths are possible for VPN traffic from end to end. Each interface on a peer can communicate with both interfaces on the other peer. This ensures that a VPN will be available as long as each peer has one working connection to the Internet.

You configure a VPN and an entry in the routing table for each of the four paths. All of these VPNs are ready to carry data. You set different routing distances for each route and only the shortest distance route is used. If this route fails, the route with the next shortest distance is used.

The redundant configurations described in this chapter use route-based VPNs, otherwise known as virtual IPsec interfaces. This means that the FortiGate unit must operate in NAT mode. You must use auto-keying. A VPN that is created using manual keys cannot be included in a redundant-tunnel configuration.

The configuration described here assumes that your redundant VPNs are essentially equal in cost and capability. When the original VPN returns to service, traffic continues to use the replacement VPN until the replacement VPN fails. If your redundant VPN uses more expensive facilities, you want to use it only as a backup while the main VPN is down. For information on how to do this, see Configuration overview on page 157. 157

Redundant VPN configurations                                                                                            Configuration overview

Example redundant-tunnel configuration

A VPN that is created using manual keys cannot be included in a redundant-tunnel configuration.

General configuration steps

A redundant configuration at each VPN peer includes:

• One Phase 1 configuration (virtual IPsec interface) for each path between the two peers. In a fully-meshed redundant configuration, each network interface on one peer can communicate with each network interface on the remote peer. If both peers have two public interfaces, this means that each peer has four paths, for example.
• One Phase 2 definition for each Phase 1 configuration.
• One static route for each IPsec interface, with different distance values to prioritize the routes.
• Two Accept security policies per IPsec interface, one for each direction of traffic. l Dead peer detection enabled in each Phase 1 definition.

The procedures in this section assume that two separate interfaces to the Internet are available on each VPN peer.

Redundant VPN configurations

Configuring the VPN peers – route-based VPN

VPN peers are configured using Interface Mode for redundant tunnels.

Configure each VPN peer as follows:

1. Ensure that the interfaces used in the VPN have static IP addresses.
2. Create a Phase 1 configuration for each of the paths between the peers.
3. Enable dead peer detection so that one of the other paths is activated if this path fails.
4. Enter these settings in particular, and any other VPN settings as required:

Path 1

Path 2

Path 3

Path 4

For more information, see Phase 1 parameters on page 52.

Redundant VPN configurations                                                                                             Configuration overview

5. Create a Phase 2 definition for each path. See Phase 2 parameters on page 72. Select the Phase 1 configuration (virtual IPsec interface) that you defined for this path. You can select the name from the Static IP Address part of the list.
6. Create a route for each path to the other peer. If there are two ports on each peer, there are four possible paths between the peer devices.

7. Define the security policy for the local primary interface. See Defining VPN security policies on page 1. You need to create two policies for each path to enable communication in both directions. Enter these settings in particular:

8. Select Create New, leave the Policy Type as Firewall and leave the Policy Subtype as Address, and enter these settings:

9. Place the policy in the policy list above any other policies having similar source and destination addresses.
10. Repeat this procedure at the remote FortiGate unit.

Redundant VPN configurations

Creating a backup IPsec interface

You can configure a route-based VPN that acts as a backup facility to another VPN. It is used only while your main VPN is out of service. This is desirable when the redundant VPN uses a more expensive facility.

You can configure a backup IPsec interface only in the CLI. The backup feature works only on interfaces with static addresses that have dead peer detection enabled. The monitor option creates a backup VPN for the specified Phase 1 configuration.

In the following example, backup_vpn is a backup for main_vpn.

config vpn ipsec phase1-interface edit main_vpn set dpd on set interface port1 set nattraversal enable set psksecret “hard-to-guess” set remote-gw 192.168.10.8 set type static

end edit backup_vpn set dpd on set interface port2 set monitor main_vpn set nattraversal enable set psksecret “hard-to-guess” set remote-gw 192.168.10.8 set type static end

Transparent mode VPNs

This section describes transparent VPN configurations, in which two FortiGate units create a VPN tunnel between two separate private networks transparently.

The following topics are included in this section: Configuration overview

Configuration overview

In transparent mode, all interfaces of the FortiGate unit except the management interface (which by default is assigned IP address 10.10.10.1/255.255.255.0) are invisible at the network layer. Typically, when a FortiGate unit runs in transparent mode, different network segments are connected to the FortiGate interfaces. The figure below shows the management station on the same subnet. The management station can connect to the FortiGate unit directly through the web-based manager.

Management station on internal network

An edge router typically provides a public connection to the Internet and one interface of the FortiGate unit is connected to the router. If the FortiGate unit is managed from an external address (see the figure below), the router must translate (NAT) a routable address to direct management traffic to the FortiGate management interface.

Management station on external network

Transparent mode VPNs

In a transparent VPN configuration, two FortiGate units create a VPN tunnel between two separate private networks transparently. All traffic between the two networks is encrypted and protected by FortiGate security policies.

Both FortiGate units may be running in transparent mode, or one could be running in transparent mode and the other running in NAT mode. If the remote peer is running in NAT mode, it must have a static public IP address.

VPNs between two FortiGate units running in transparent mode do not support inbound/outbound NAT (supported through CLI commands) within the tunnel. In addition, a FortiGate unit running in transparent mode cannot be used in a hub-andspoke configuration.

Encrypted packets from the remote VPN peer are addressed to the management interface of the local FortiGate unit. If the local FortiGate unit can reach the VPN peer locally, a static route to the VPN peer must be added to the routing table on the local FortiGate unit. If the VPN peer connects through the Internet, encrypted packets from the local FortiGate unit must be routed to the edge router instead. For information about how to add a static route to the FortiGate routing table, see the Advanced Routing Guide.

In the example configuration shown above, Network Address Translation (NAT) is enabled on the router. When an encrypted packet from the remote VPN peer arrives at the router through the Internet, the router performs inbound NAT and forwards the packet to the FortiGate unit. Refer to the software supplier’s documentation to configure the router.

If you want to configure a VPN between two FortiGate units running in transparent mode, each unit must have an independent connection to a router that acts as a gateway to the Internet, and both units must be on separate networks that have a different address space. When the two networks linked by the VPN tunnel have different address spaces (see the figure below), at least one router must separate the two FortiGate units, unless the packets can be redirected using ICMP (as shown in the following figure).

Link between two FortiGate units in transparent mode

In the figure below, interface C behind the router is the default gateway for both FortiGate units. Packets that cannot be delivered on Network_1 are routed to interface C by default. Similarly, packets that cannot be delivered on Network_2 are routed to interface C. In this case, the router must be configured to redirect packets destined for Network_1 to interface A and redirect packets destined for Network_2 to interface B.

Transparent mode VPNs                                                                                                                           overview

ICMP redirecting packets to two FortiGate units in transparent mode

If there are additional routers behind the FortiGate unit (see the figure below) and the destination IP address of an inbound packet is on a network behind one of those routers, the FortiGate routing table must include routes to those networks. For example, in the following figure, the FortiGate unit must be configured with static routes to interfaces A and B in order to forward packets to Network_1 and Network_2 respectively.

Destinations on remote networks behind internal routers

Transparent VPN infrastructure requirements

• The local FortiGate unit must be operating in transparent mode.
• The management IP address of the local FortiGate unit specifies the local VPN gateway. The management IP address is considered a static IP address for the local VPN peer.
• If the local FortiGate unit is managed through the Internet, or if the VPN peer connects through the Internet, the edge router must be configured to perform inbound NAT and forward management traffic and/or encrypted packets to the FortiGate unit.
• If the remote peer is operating in NAT mode, it must have a static public IP address.

Transparent mode VPNs

A FortiGate unit operating in transparent mode requires the following basic configuration to operate as a node on the IP network:

• The unit must have sufficient routing information to reach the management station.
• For any traffic to reach external destinations, a default static route to an edge router that forwards packets to the Internet must be present in the FortiGate routing table.
• When all of the destinations are located on the external network, the FortiGate unit may route packets using a single default static route. If the network topology is more complex, one or more static routes in addition to the default static route may be required in the FortiGate routing table.

Only policy-based VPN configurations are possible in transparent mode.

Before you begin

An IPsec VPN definition links a gateway with a tunnel and an IPsec policy. If your network topology includes more than one virtual domain, you must choose components that were created in the same virtual domain. Therefore, before you define a transparent VPN configuration, choose an appropriate virtual domain in which to create the required interfaces, security policies, and VPN components. For more information, see the Virtual Domains guide.

Configuring the VPN peers

1. The local VPN peer need to operate in transparent mode.

To determine if your FortiGate unit is in transparent mode, go to the Dashboard > System Information widget.

Select [change]. Select transparent for the Operation Mode. Two new fields will appear to enter the

Management IP/Netmask, and the Default Gateway.

In transparent mode, the FortiGate unit is invisible to the network. All of its interfaces are on the same subnet and share the same IP address. You only have to configure a management IP address so that you can make configuration changes.

The remote VPN peer may operate in NAT mode or transparent mode.

2. At the local FortiGate unit, define the Phase 1 parameters needed to establish a secure connection with the remote peer. See Phase 1 parameters on page 52. Select Advanced and enter these settings in particular:

3. Define the Phase 2 parameters needed to create a VPN tunnel with the remote peer. See Phase 2 parameters on page 72. Select the set of Phase 1 parameters that you defined for the remote peer. The name of the remote peer can be selected from the Static IP Address
4. Define the source and destination addresses of the IP packets that are to be transported through the VPN tunnel. See Defining VPN security policies on page 1. Enter these settings in particular:

Transparent mode VPNs                                                                                                                           overview

• For the originating address (source address), enter the IP address and netmask of the private network behind the local peer network. for the management interface, for example, 10.10.0/24. This address needs to be a range to allow traffic from your network through the tunnel. Optionally select any for this address.
• For the remote address (destination address), enter the IP address and netmask of the private network behind the remote peer (for example, 168.10.0/24). If the remote peer is a FortiGate unit running in transparent mode, enter the IP address of the remote management interface instead.

5. Define an IPsec security policy to permit communications between the source and destination addresses. See Defining VPN security policies on page 1. Enter these settings in particular:

6. Place the policy in the policy list above any other policies having similar source and destination addresses.
7. Define another IPsec security policy to permit communications between the source and destination addresses in the opposite direction. This security policy and the previous one form a bi-directional policy pair. See Defining VPN security policies on page 1. Enter these settings in particular:

8. Repeat this procedure at the remote FortiGate unit to create bidirectional security policies. Use the local interface and address information local to the remote FortiGate unit.

For more information on transparent mode, see the System Administration Guide.

IPv6 IPsec VPNs

This chapter describes how to configure your FortiGate unit’s IPv6 IPsec VPN functionality.

By default IPv6 configurations to not appear on the Web-based Manager. You need to enable the feature first.

                                    To enable IPv6

1. Go to System > Feature Visibility.
2. Enable IPv6.
3. Select Apply.

The following topics are included in this section: Configuration examples

IPv6 IPsec support

FortiOS supports route-based IPv6 IPsec, but not policy-based. This section describes how IPv6 IPsec support differs from IPv4 IPsec support. FortiOS 4.0 MR3 is IPv6 Ready Logo Program Phase 2 certified.

Where both the gateways and the protected networks use IPv6 addresses, sometimes called IPv6 over IPv6, you can create either an auto-keyed or manually-keyed VPN. You can combine IPv6 and IPv4 addressing in an autokeyed VPN in the following ways:

Compared with IPv4 IPsec VPN functionality, there are some limitations:

• Except for IPv6 over IPv4, remote gateways with Dynamic DNS are not supported.
• Selectors cannot be firewall address names. Only IP address, address range and subnet are supported.
• Redundant IPv6 tunnels are not supported.

Certificates

On a VPN with IPv6 Phase 1 configuration, you can authenticate using VPN certificates in which the common name (cn) is an IPv6 address. The cn-type keyword of the user peer command has an option, ipv6, to support this.

Configuration examples

This section consists of the following configuration examples:

• Site-to-site IPv6 over IPv6 VPN example
• Site-to-site IPv6 over IPv4 VPN example
• Site-to-site IPv4 over IPv6 VPN example

Site-to-site IPv6 over IPv6 VPN example

In this example, computers on IPv6-addressed private networks communicate securely over public IPv6 infrastructure.

By default IPv6 configurations to not appear on the Web-based Manager. You need to enable the feature first.

                                    To enable IPv6

1. Go to System > Feature Visibility.
2. Enable IPv6.
3. Select Apply.

Example IPv6-over-IPv6 VPN topology

Configure FortiGate A interfaces

Port 2 connects to the public network and port 3 connects to the local network.

config system interface edit port2 config ipv6 set ip6-address fec0::0001:209:0fff:fe83:25f2/64

end

next edit port3 config ipv6 set ip6-address fec0::0000:209:0fff:fe83:25f3/64

end

next

end

Configure FortiGate A IPsec settings

The Phase 1 configuration creates a virtual IPsec interface on port 2 and sets the remote gateway to the public IP address FortiGate B. This configuration is the same as for an IPv4 route-based VPN, except that ip-version is set to 6 and the remote-gw6 keyword is used to specify an IPv6 remote gateway address.

config vpn ipsec phase1-interface edit toB set ip-version 6 set interface port2

set remote-gw6 fec0:0000:0000:0003:209:0fff:fe83:25c7 set dpd [disable | on-idle | on-demand] set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

By default, Phase 2 selectors are set to accept all subnet addresses for source and destination. The default setting for src-addr-type and dst-addr-type is subnet. The IPv6 equivalent is subnet6. The default subnet addresses are 0.0.0.0/0 for IPv4, ::/0 for IPv6.

config vpn ipsec phase2-interface edit toB2 set phase1name toB set proposal 3des-md5 3des-sha1 set pfs enable set replay enable set src-addr-type subnet6 set dst-addr-type subnet6

end

Configure FortiGate A security policies

Security policies are required to allow traffic between port3 and the IPsec interface toB in each direction. The address all6 must be defined using the firewall address6 command as ::/0.

config firewall policy6 edit 1 set srcintf port3 set dstintf toB set srcaddr all6 set dstaddr all6

set action accept set service ANY set schedule always

next edit 2 set srcintf toB set dstintf port3 set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

end

Configure FortiGate A routing

This simple example requires just two static routes. Traffic to the protected network behind FortiGate B is routed via the virtual IPsec interface toB. A default route sends all IPv6 traffic out on port2.

config router static6 edit 1 set device port2 set dst 0::/0

next edit 2 set device toB

set dst fec0:0000:0000:0004::/64

end

Configure FortiGate B

The configuration of FortiGate B is very similar to that of FortiGate A. A virtual IPsec interface toA is configured on port2 and its remote gateway is the public IP address of FortiGate A. Security policies enable traffic to pass between the private network and the IPsec interface. Routing ensures traffic for the private network behind FortiGate A goes through the VPN and that all IPv6 packets are routed to the public network.

config system interface edit port2 config ipv6 set ip6-address fec0::0003:209:0fff:fe83:25c7/64

end

next edit port3 config ipv6 set ip6-address fec0::0004:209:0fff:fe83:2569/64

end

end

config vpn ipsec phase1-interface edit toA set ip-version 6 set interface port2

set remote-gw6 fec0:0000:0000:0001:209:0fff:fe83:25f2 set dpd [disable | on-idle | on-demand] set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

config vpn ipsec phase2-interface edit toA2

set phase1name toA set proposal 3des-md5 3des-sha1 set pfs enable set replay enable set src-addr-type subnet6 set dst-addr-type subnet6

end

config firewall policy6 edit 1 set srcintf port3 set dstintf toA set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

next edit 2 set srcintf toA set dstintf port3 set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

end

config router static6 edit 1 set device port2 set dst 0::/0

next edit 2 set device toA

set dst fec0:0000:0000:0000::/64

end

Site-to-site IPv6 over IPv4 VPN example

In this example, IPv6-addressed private networks communicate securely over IPv4 public infrastructure.

Example IPv6-over-IPv4 VPN topology

Configure FortiGate A interfaces

Port 2 connects to the IPv4 public network and port 3 connects to the IPv6 LAN.

config system interface edit port2 set 10.0.0.1/24 next edit port3 config ipv6 set ip6-address fec0::0001:209:0fff:fe83:25f3/64

end

Configure FortiGate A IPsec settings

The Phase 1 configuration uses IPv4 addressing.

config vpn ipsec phase1-interface edit toB set interface port2 set remote-gw 10.0.1.1

set dpd [disable | on-idle | on-demand] set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

The Phase 2 configuration uses IPv6 selectors. By default, Phase 2 selectors are set to accept all subnet addresses for source and destination. The default setting for src-addr-type and dst-addr-type is subnet. The IPv6 equivalent is subnet6. The default subnet addresses are 0.0.0.0/0 for IPv4, ::/0 for IPv6.

config vpn ipsec phase2-interface edit toB2 set phase1name toB set proposal 3des-md5 3des-sha1 set pfs enable set replay enable set src-addr-type subnet6 set dst-addr-type subnet6

end

Configure FortiGate A security policies

IPv6 security policies are required to allow traffic between port3 and the IPsec interface toB in each direction. Define the address all6 using the firewall address6 command as ::/0.

config firewall policy6 edit 1 set srcintf port3 set dstintf toB set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

next edit 2 set srcintf toB set dstintf port3 set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

end

Configure FortiGate A routing

This simple example requires just two static routes. Traffic to the protected network behind FortiGate B is routed via the virtual IPsec interface toB using an IPv6 static route. A default route sends all IPv4 traffic, including the IPv4 IPsec packets, out on port2.

config router static6 edit 1 set device toB

set dst fec0:0000:0000:0004::/64

end

config router static edit 1 set device port2 set dst 0.0.0.0/0 set gateway 10.0.0.254

end

Configure FortiGate B

The configuration of FortiGate B is very similar to that of FortiGate A. A virtual IPsec interface toA is configured on port2 and its remote gateway is the IPv4 public IP address of FortiGate A. The IPsec Phase 2 configuration has IPv6 selectors.

IPv6 security policies enable traffic to pass between the private network and the IPsec interface. An IPv6 static route ensures traffic for the private network behind FortiGate A goes through the VPN and an IPv4 static route ensures that all IPv4 packets are routed to the public network.

config system interface edit port2 set 10.0.1.1/24

next edit port3 config ipv6 set ip6-address fec0::0004:209:0fff:fe83:2569/64

end

config vpn ipsec phase1-interface edit toA set interface port2 set remote-gw 10.0.0.1

set dpd [disable | on-idle | on-demand] set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

config vpn ipsec phase2-interface edit toA2 set phase1name toA set proposal 3des-md5 3des-sha1 set pfs enable set replay enable set src-addr-type subnet6 set dst-addr-type subnet6

end

config firewall policy6 edit 1 set srcintf port3 set dstintf toA set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

next edit 2 set srcintf toA set dstintf port3 set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

end

config router static6 edit 1 set device toA

set dst fec0:0000:0000:0000::/64

end

config router static edit 1 set device port2

set gateway 10.0.1.254

end

Site-to-site IPv4 over IPv6 VPN example

In this example, two private networks with IPv4 addressing communicate securely over IPv6 infrastructure.

Example IPv4-over-IPv6 VPN topology

Configure FortiGate A interfaces

Port 2 connects to the IPv6 public network and port 3 connects to the IPv4 LAN.

config system interface edit port2 config ipv6 set ip6-address fec0::0001:209:0fff:fe83:25f2/64

end

next edit port3 set 192.168.2.1/24

end

Configure FortiGate A IPsec settings

The Phase 1 configuration is the same as in the IPv6 over IPv6 example.

config vpn ipsec phase1-interface edit toB set ip-version 6 set interface port2

set remote-gw6 fec0:0000:0000:0003:209:0fff:fe83:25c7 set dpd [disable | on-idle | on-demand] set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

The Phase 2 configuration is the same as you would use for an IPv4 VPN. By default, Phase 2 selectors are set to accept all subnet addresses for source and destination.

config vpn ipsec phase2-interface edit toB2 set phase1name toB set proposal 3des-md5 3des-sha1 set pfs enable set replay enable

end

Configure FortiGate A security policies

Security policies are required to allow traffic between port3 and the IPsec interface toB in each direction. These are IPv4 security policies.

config firewall policy edit 1 set srcintf port3 set dstintf toB set srcaddr all set dstaddr all set action accept set service ANY set schedule always

next edit 2 set srcintf toB set dstintf port3 set srcaddr all set dstaddr all set action accept set service ANY set schedule always

end

Configure FortiGate A routing

This simple example requires just two static routes. Traffic to the protected network behind FortiGate B is routed via the virtual IPsec interface toB using an IPv4 static route. A default route sends all IPv6 traffic, including the IPv6 IPsec packets, out on port2.

config router static6 edit 1 set device port2 set dst 0::/0

next edit 2 set device toB set dst 192.168.3.0/24 end

Configure FortiGate B

The configuration of FortiGate B is very similar to that of FortiGate A. A virtual IPsec interface toA is configured on port2 and its remote gateway is the public IP address of FortiGate A. The IPsec Phase 2 configuration has IPv4 selectors.

IPv4 security policies enable traffic to pass between the private network and the IPsec interface. An IPv4 static route ensures traffic for the private network behind FortiGate A goes through the VPN and an IPv6 static route ensures that all IPv6 packets are routed to the public network.

config system interface edit port2 config ipv6 set ip6-address fec0::0003:fe83:25c7/64

end

next edit port3 set 192.168.3.1/24

end

config vpn ipsec phase1-interface edit toA set ip-version 6 set interface port2

set remote-gw6 fec0:0000:0000:0001:209:0fff:fe83:25f2 set dpd [disable | on-idle | on-demand] set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

config vpn ipsec phase2-interface edit toA2 set phase1name toA set proposal 3des-md5 3des-sha1 set pfs enable set replay enable

end

config firewall policy edit 1 set srcintf port3 set dstintf toA set srcaddr all set dstaddr all set action accept set service ANY set schedule always

next edit 2 set srcintf toA set dstintf port3 set srcaddr all set dstaddr all set action accept set service ANY set schedule always

end

config router static6 edit 1 set device port2

set dst 0::/0

next edit 2

set device toA set dst 192.168.2.0/24 end

L2TP and IPsec (Microsoft VPN)

This section describes how to set up a VPN that is compatible with the Microsoft Windows native VPN, which is Layer 2 Tunneling Protocol (L2TP) with IPsec encryption.

The following topics are included in this section:

Overview

Assumptions

Configuration overview

For troubleshooting information, refer to Troubleshooting L2TP and IPsec.

Overview

The topology of a VPN for Microsoft Windows dialup clients is very similar to the topology for FortiClient Endpoint Security clients.

Example FortiGate VPN configuration with Microsoft clients

Assumptions

For users, the difference is that instead of installing and using the FortiClient application, they configure a network connection using the software built into the Microsoft Windows operating system. Starting in FortiOS 4.0 MR2, you can configure a FortiGate unit to work with unmodified Microsoft VPN client software.

Layer 2 Tunneling Protocol (L2TP)

L2TP is a tunneling protocol published in 1999 that is used with VPNs, as the name suggests. Microsoft Windows operating system has a built-in L2TP client starting since Windows 2000. Mac OS X 10.3 system and higher also have a built-in client.

L2TP provides no encryption and used UDP port 1701. IPsec is used to secure L2TP packets. The initiator of the L2TP tunnel is called the L2TP Access Concentrator (LAC).

L2TP and IPsec is supported for native Windows XP, Windows Vista and Mac OSX native VPN clients. However, in Mac OSX (OSX 10.6.3, including patch releases) the L2TP feature does not work properly on the Mac OS side.

Assumptions

The following assumptions have been made for this example:

• L2TP protocol traffic is allowed through network firewalls (TCP and UDP port 1701)
• User has Microsoft Windows 2000 or higher — a Windows version that supports L2TP

Configuration overview

The following section consists of configuring the FortiGate unit and configuring the Windows PC.

Configuring the FortiGate unit

To configure the FortiGate unit, you must:

• Configure LT2P users and firewall user group.
• Configure the L2TP VPN, including the IP address range it assigns to clients.
• Configure an IPsec VPN with encryption and authentication settings that match the Microsoft VPN client.
• Configure security policies.

Configuring LT2P users and firewall user group

Remote users must be authenticated before they can request services and/or access network resources through the VPN. The authentication process can use a password defined on the FortiGate unit or an established external authentication mechanism such as RADIUS or LDAP.

Creating user accounts

You need to create user accounts and then add these users to a firewall user group to be used for L2TP authentication. The Microsoft VPN client can automatically send the user’s Window network logon credentials. You might want to use these for their L2TP user name and password.

Creating a user account – web-based manager

1. Go to User & Device > User Definitionand select Create New.
2. Enter the User Name.
3. Do one of the following:

l Select Password and enter the user’s assigned password.

 l Select Match user on LDAP server, Match user on RADIUS server, or Match user onTACACS+

server and select the authentication server from the list. The authentication server must be already configured on the FortiGate unit.

4. Select OK.

Creating a user account – CLI

To create a user account called user1 with the password 123_user, enter:

config user local edit user1 set type password set passwd “123_user” set status enable

end

Creating a user group

When clients connect using the L2TP-over-IPsec VPN, the FortiGate unit checks their credentials against the user group you specify for L2TP authentication. You need to create a firewall user group to use for this purpose.

Creating a user group – web-based manager

1. Go to User & Device > User Groups, select Create New, and enter the following:

2. Select OK.

Creating a user group – CLI

To create the user group L2TP_group and add members User_1, User_2, and User_3, enter:

config user group edit L2TP_group set group-type firewall set member User_1 User_2 User_3 end

Configuring L2TP

You can only configure L2TP settings in the CLI. As well as enabling L2TP, you set the range of IP address values that are assigned to L2TP clients and specify the user group that can access the VPN. For example, to allow access to users in the L2TP_group and assign them addresses in the range 192.168.0.50 to 192.168.0.59, enter:

config vpn l2tp set sip 192.168.0.50 set eip 192.168.0.59 set status enable set usrgrp “L2TP_group”

end

One of the security policies for the L2TP over IPsec VPN uses the client address range, so you need also need to create a firewall address for that range. For example,

config firewall address edit L2TPclients set type iprange set start-ip 192.168.0.50 set end-ip 192.168.0.59

end

Alternatively, you could define this range in the web-based manager.

Configuring IPsec

The Microsoft VPN client uses IPsec for encryption. The configuration needed on the FortiGate unit is the same as for any other IPsec VPN with the following exceptions.

• Transport mode is used instead of tunnel mode.
• The encryption and authentication proposals must be compatible with the Microsoft client.

L2TP over IPsec is supported on the FortiGate unit for both policy-based and route-based configurations, but the following example is policy-based.

Configuring Phase 1 – web-based manager

1. Go to VPN > IPsec Tunnels and create the new custom tunnel or edit an existing tunnel.
2. Edit the Phase 1 Proposal (if it is not available, you may need to click the Convert to Custom Tunnel button).

Configuring Phase 1 – CLI

To create a Phase 1 configuration called dialup_p1 on a FortiGate unit that has port1 connected to the Internet, you would enter:

config vpn ipsec phase1 edit dialup_p1 set type dynamic set interface port1 set mode main set psksecret ********

set proposal aes256-md5 3des-sha1 aes192-sha1 set dhgrp 2 set nattraversal enable

set dpd [disable | on-idle | on-demand]

end

It is worth noting here that the command config vpn ipsec phase1 is used rather than config vpn ipsec phase1-interface because this configuration is policy-based and not route-based.

Configuring Phase 2 – web-based manager

1. Open the Phase 2 Selectors
2. Enter the following information and then select OK.

3. Make this a transport-mode VPN. You must use the CLI to do this. If your Phase 2 name is dialup_p2, you would enter:

config vpn ipsec phase2 edit dialup_p2 set encapsulation transport-mode

end

Configuring Phase 2 – CLI

To configure a Phase 2 to work with your phase_1 configuration, you would enter:

config vpn ipsec phase2 edit dialup_p2 set phase1name dialup_p1

set proposal aes256-md5 3des-sha1 aes192-sha1 set replay enable set pfs disable set keylifeseconds 3600 set encapsulation transport-mode

end

Once again, note here that the command config vpn ipsec phase2 is used rather than config vpn ipsec phase2-interface because this configuration is policy-based and not route-based.

Configuring security policies

The security policies required for L2TP over IPsec VPN are:

• An IPsec policy, as you would create for any policy-based IPsec VPN
• A regular ACCEPT policy to allow traffic from the L2TP clients to access the protected network

Configuring the IPsec security policy – web-based manager

1. Go to System > Feature Visibility and enable Policy-based IPsec VPN.
2. Go to Policy & Objects > IPv4 Policy and select Create New.
3. Set the Action to IPsec and enter the following information:

4. Select OK.

Configuring the IPsec security policy – CLI

If your VPN tunnel (Phase 1) is called dialup_p1, your protected network is on port2, and your public interface is port1, you would enter:

config firewall policy edit 0 set srcintf port2 set dstintf port1 set srcaddr all set dstaddr all set action ipsec set schedule always set service all set inbound enable set vpntunnel dialup_p1

end

Configuring the ACCEPT security policy – web-based manager

1. Go to Policy & Objects > IPv4 Policy and select Create New.
2. Leave the Policy Type as Firewall and leave the Policy Subtype as Address.
3. Enter the following information and select OK:

Configuring the ACCEPT security policy – CLI

If your public interface is port1, your protected network is on port2, and L2TPclients is the address range that L2TP clients use, you would enter: config firewall policy

edit 1 set srcintf port1 set dstintf port2 set srcaddr L2TPclients set dstaddr all set action accept set schedule always set service all

end

Configuring the Windows PC

Configuration of the Windows PC for a VPN connection to the FortiGate unit consists of the following:

1. In Network Connections, configure a Virtual Private Network connection to the FortiGate unit.
2. Ensure that the IPSEC service is running.
3. Ensure that IPsec has not been disabled for the VPN client. It may have been disabled to make the Microsoft VPN compatible with an earlier version of FortiOS.

The instructions in this section are based on Windows XP. Other versions of Windows may vary slightly.

Configuring the network connection

1. Open Network Connections.

This is available through the Control Panel.

2. Double-click New Connection Wizard and Select Next.
3. Select Connect to the network at my workplace.
4. Select Next.
5. Select Virtual Private Network connection and select Next.
6. In the Company Name field, enter a name for the connection and select Next.
7. Select Do not dial the initial connection and then select Next.
8. Enter the public IP address or FQDN of the FortiGate unit and select Next.
9. Optionally, select Add a shortcut to this connection to my desktop.
10. Select Finish.

The Connect dialog opens on the desktop.

11. Select Properties and then select the Security
12. Select IPsec Settings.
13. Select Use pre-shared key for authentication, enter the preshared key that you configured for your VPN, and select OK. Select OK.

Checking that the IPsec service is running

1. Open Administrative Tools through the Control Panel.
2. Double-click Services.
3. Look for IPSEC Services. Confirm that the Startup Type is Automatic and Status is set to Started. If needed, double-click IPsec Services to change these settings.

Checking that IPsec has not been disabled

1. Select Start > Run.
2. Enter regedit and select OK.
3. Find the Registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters
4. If there is a ProhibitIPsec value, it must be set to 0.

Enforcing IPsec in L2TP configuration

An enforce-ipsec option is available in L2TP configuration to force the FortiGate L2TP server to accept only IPsec encrypted connections.

Syntax

config vpn l2tp set eip 50.0.0.100 set sip 50.0.0.1 set status enable

set enforce-ipsec-interface {disable | enable}      (default = disable) set usrgrp <group_name> end

GRE over IPsec (Cisco VPN)

This section describes how to configure a FortiGate VPN that is compatible with Cisco-style VPNs that use GRE in an IPsec tunnel.

The following topics are included in this section:

Configuration overview

Configuring the Cisco router

Keep-alive support for GRE

Cisco products that include VPN support often use Generic Routing Encapsulation (GRE) protocol tunnel over

IPsec encryption. This chapter describes how to configure a FortiGate unit to work with this type of Cisco VPN.

Cisco VPNs can use either transport mode or tunnel mode IPsec. Before FortiOS 4.0 MR2, the FortiGate unit was compatible only with tunnel mode IPsec.

Example FortiGate to Cisco GRE-over-IPsec VPN

In this example, users on LAN1 are provided access to LAN2.

Configuration overview

The following section consists of configuring the FortiGate unit and configuring the Cisco router.

Configuring the FortiGate unit

There are several steps to the GRE-over-IPsec configuration:

• Enable overlapping subnets. This is needed because the IPsec and GRE tunnels will use the same addresses.
• Configure a route-based IPsec VPN on the external interface.
• Configure a GRE tunnel on the virtual IPsec interface. Set its local gateway and remote gateway addresses to match the local and remote gateways of the IPsec tunnel.
• Configure security policies to allow traffic to pass in both directions between the GRE virtual interface and the IPsec virtual interface.
• Configure security policies to allow traffic to pass in both directions between the protected network interface and the GRE virtual interface.
• Configure a static route to direct traffic destined for the network behind the Cisco router into the GRE-over-IPsec tunnel.

Enabling overlapping subnets

By default, each FortiGate unit network interface must be on a separate network. The configuration described in this chapter assigns an IPsec tunnel end point and the external interface to the same network. Enable subnet overlap as follows:

config system settings set allow-subnet-overlap enable

end

Configuring the IPsec VPN

A route-based VPN is required. It must use encryption and authentication algorithms compatible with the Cisco equipment to which it connects. In this chapter, preshared key authentication is shown.

Configuring the IPsec VPN – web-based manager

1. Define the Phase 1 configuration needed to establish a secure connection with the remote Cisco device. Enter these settings in particular:

Configuration overview

For more information about these settings, see Phase 1 parameters on page 52.

2. Define the Phase 2 parameters needed to create a VPN tunnel with the remote peer. For compatibility with the Cisco router, Quick Mode Selectors must be entered, which includes specifying protocol 47, the GRE protocol. Enter these settings in particular:

For more information about these settings, see Phase 2 parameters on page 72.

3. If the Cisco device is configured to use transport mode IPsec, you need to use transport mode on the FortiGate VPN. You can configure this only in the CLI. In your Phase 2 configuration, set encapsulation to transport-mode as follows:

config vpn phase2-interface edit to_cisco_p2 set encapsulation transport-mode

end

Configuring the IPsec VPN – CLI

config vpn ipsec phase1-interface edit tocisco set interface port1

set proposal 3des-sha1 aes128-sha1

set remote-gw 192.168.5.113 set psksecret xxxxxxxxxxxxxxxx

end

config vpn ipsec phase2-interface edit tocisco_p2 set phase1name “tocisco” set proposal 3des-md5 set encapsulation tunnel-mode // if tunnel mode set encapsulation transport-mode  // if transport mode set protocol 47 set src-addr-type ip set dst-start-ip 192.168.5.113 set src-start-ip 172.20.120.141

end

Adding IPsec tunnel end addresses

The Cisco configuration requires an address for its end of the IPsec tunnel. The addresses are set to match the GRE gateway addresses. Use the CLI to set the addresses, like this:

config system interface edit tocisco set ip 172.20.120.141 255.255.255.255 set remote-ip 192.168.5.113

end

Configuring the GRE tunnel

The GRE tunnel runs between the virtual IPsec public interface on the FortiGate unit and the Cisco router. You must use the CLI to configure a GRE tunnel. In the example, you would enter:

config system gre-tunnel edit gre1 set interface tocisco set local-gw 172.20.120.141 set remote-gw 192.168.5.113

end

interface is the virtual IPsec interface, local-gw is the FortiGate unit public IP address, and remote-gw is the remote Cisco device public IP address

Adding GRE tunnel end addresses

You will also need to add tunnel end addresses. The Cisco router configuration requires an address for its end of the GRE tunnel. Using the CLI, enter tunnel end addresses that are not used elsewhere on the FortiGate unit, like this:

config system interface edit gre1 set ip 10.0.1.1 255.255.255.255 set remote-ip 10.0.1.2

end

Configuring security policies

Two sets of security policies are required:

Configuration overview

• Policies to allow traffic to pass in both directions between the GRE virtual interface and the IPsec virtual interface.
• Policies to allow traffic to pass in both directions between the protected network interface and the GRE virtual interface.

Configuring security policies – web-based manager

1. Define an ACCEPT firewall security policy to permit communications between the protected network and the GRE tunnel:

2. To permit the remote client to initiate communication, you need to define a firewall address security policy for communication in that direction:

3. Define a pair of ACCEPT firewall address security policies to permit traffic to flow between the GRE virtual interface and the IPsec virtual interface:

Configuring security policies – CLI

config firewall policy edit 1 // LAN to GRE tunnel set srcintf port2 set dstintf gre1 set srcaddr all set dstaddr all set action accept set schedule always set service ANY

next edit 2 // GRE tunnel to LAN set srcintf gre1 set dstintf port2 set srcaddr all set dstaddr all set action accept set schedule always set service ANY

next

edit 3 // GRE tunnel to IPsec interface set srcintf “gre1” set dstintf “tocisco” set srcaddr “all” set dstaddr “all” set action accept set schedule “always” set service “ANY”

next

edit 4 // IPsec interface to GRE tunnel

set srcintf “tocisco” set dstintf “gre1” set srcaddr “all” set dstaddr “all” set action accept set schedule “always” set service “ANY” end

Configuring the Cisco router

Configuring routing

Traffic destined for the network behind the Cisco router must be routed to the GRE tunnel. To do this, create a static route

1. Go to Network > Static Routes and select Create New. 2. Enter the following information and select OK.

In the CLI, using the example values, you would enter

config router static edit 0 set device gre1

set dst 10.21.101.0 255.255.255.0

end

Configuring the Cisco router

Using Cisco IOS, you would configure the Cisco router as follows, using the addresses from the example:

config ter

crypto ipsec transform-set myset esp-3des esp-md5-hmac no mode exit no ip access-list extended tunnel ip access-list extended tunnel

permit gre host 192.168.5.113 host 172.20.120.141 exit

interface Tunnel1

ip address 10.0.1.2 255.255.255.0 tunnel source 192.168.5.113 tunnel destination 172.20.120.141 ! ip route 10.11.101.0 255.255.255.0 Tunnel1 end clea crypto sa clea crypto isakmp

For transport mode, change no mode to mode transport.

This is only the portion of the Cisco router configuration that applies to the GRE-over-IPsec tunnel. For more information, refer to the Cisco documentation.

Keep-alive support for GRE

Keep-alive support for GRE

The FortiGate can send a GRE keep-alive response to a Cisco device to detect a GRE tunnel. If it fails, it will remove any routes over the GRE interface.

Syntax

config system gre-tunnel edit <id> set keepalive-interval <value: 0-32767> set keepalive-failtimes <value: 1-255>

next end

Protecting OSPF with IPsec

For enhanced security, OSPF dynamic routing can be carried over IPsec VPN links. The following topics are included in this section:

Configuration overview

This chapter shows an example of OSPF routing conducted over an IPsec tunnel between two FortiGate units. The network shown below is a single OSPF area. FortiGate_1 is an Area border router that advertises a static route to 10.22.10.0/24 in OSPF. FortiGate_2 advertises its local LAN as an OSPF internal route.

OSPF over an IPsec VPN tunnel

The section Configuration overview describes the configuration with only one IPsec VPN tunnel, tunnel_wan1. Then, the section Configuration overview  describes how you can add a second tunnel to provide a redundant backup path. This is shown above as VPN tunnel “tunnel_wan2”.

Only the parts of the configuration concerned with creating the IPsec tunnel and integrating it into the OSPF network are described. It is assumed that security policies are already in place to allow traffic to flow between the interfaces on each FortiGate unit.

OSPF over IPsec configuration

There are several steps to the OSPF-over-IPsec configuration:

• Configure a route-based IPsec VPN on an external interface. It will connect to a corresponding interface on the other FortiGate unit. Define the two tunnel-end addresses.
• Configure a static route to the other FortiGate unit.
• Configure the tunnel network as part of the OSPF network and define the virtual IPsec interface as an OSPF interface.

This section describes the configuration with only one VPN, tunnel_wan1. The other VPN is added in the section Configuration overview on page 197.

Configuring the IPsec VPN

A route-based VPN is required. In this chapter, preshared key authentication is shown. Certificate authentication is also possible. Both FortiGate units need this configuration.

Configuring Phase 1

1. Define the Phase 1 configuration needed to establish a secure connection with the other FortiGate unit. For more information, see Phase 1 parameters on page 52. Enter these settings in particular:

Assigning the tunnel end IP addresses

1. Go to Network > Interfaces, select the virtual IPsec interface that you just created on Port 2 and select Edit. 2. In the IP and Remote IP fields, enter the following tunnel end addresses:

These addresses are from a network that is not used for anything else.

Configuring Phase 2

1. Enter a name to identify this Phase 2 configuration, twan1_p2, for example.
2. Select the name of the Phase 1 configuration that you defined in Step “Configuration overview” on page 197, tunnel_wan1 for example.

Configuring static routing

You need to define the route for traffic leaving the external interface.

1. Go to Network > Static Routes, select Create New.
2. Enter the following information.

Configuring OSPF

This section does not attempt to explain OSPF router configuration. It focusses on the integration of the IPsec tunnel into the OSPF network. This is accomplished by assigning the tunnel as an OSPF interface, creating an OSPF route to the other FortiGate unit.

This configuration uses loopback interfaces to ease OSPF troubleshooting. The OSPF router ID is set to the loopback interface address.The loopback interface ensures the router is always up. Even though technically the router ID doesn’t have to match a valid IP address on the FortiGate unit, having an IP that matches the router ID makes troubleshooting a lot easier.

The two FortiGate units have slightly different configurations. FortiGate_1 is an AS border router that advertises its static default route. FortiGate_2 advertises its local LAN as an OSPF internal route.

Setting the router ID for each FortiGate unit to the lowest possible value is useful if you want the FortiGate units to be the designated router (DR) for their respective ASes. This is the router that broadcasts the updates for the AS.

Leaving the IP address on the OSPF interface at 0.0.0.0 indicates that all potential routes will be advertised, and it will not be limited to any specific subnet. For example if this IP address was 10.1.0.0, then only routes that match that subnet will be advertised through this interface in OSPF.

FortiGate_1 OSPF configuration

When configuring FortiGate_1 for OSPF, the loopback interface is created, and then you configure OSPF area networks and interfaces.

With the exception of creating the loopback interface, OSPF for this example can all be configured in either the web-based manager or CLI.

Creating the loopback interface

A loopback interface can be configured in the CLI only. For example, if the interface will have an IP address of 10.0.0.1, you would enter:

config system interface edit lback1 set vdom root set ip 10.0.0.1 255.255.255.255 set type loopback

end

The loopback addresses and corresponding router IDs on the two FortiGate units must be different. For example, set the FortiGate 1 loopback to 10.0.0.1 and the FortiGate 2 loopback to 10.0.0.2.

Configuring OSPF area, networks, and interfaces – web-based manager

1. On FortiGate_1, go to Network > OSPF.
2. Enter the following information to define the router, area, and interface information.

3. For Networks, select Create New.
4. Enter the IP/Netmask of 1.1.0/255.255.255.0 and an Area of 0.0.0.0. 5. For Networks, select Create New.
5. Enter the IP/Netmask of 0.0.1/255.255.255.0 and an Area of 0.0.0.0.
6. Select Apply.

Configuring OSPF area and interfaces – CLI

Your loopback interface is 10.0.0.1, your tunnel ends are on the 10.1.1.0/24 network, and your virtual IPsec interface is named tunnel_wan1. Enter the following CLI commands:

config router ospf set router-id 10.0.0.1 config area edit 0.0.0.0

end config network edit 4 set prefix 10.1.1.0 255.255.255.0

next edit 2 set prefix 10.0.0.1 255.255.255.255

end

config ospf-interface edit ospf_wan1 set cost 10

set interface tunnel_wan1 set network-type point-to-point

end

config redistribute connected set status enable

end

config redistribute static set status enable

end

end

FortiGate_2 OSPF configuration

When configuring FortiGate_2 for OSPF, the loopback interface is created, and then you configure OSPF area networks and interfaces.

Configuring FortiGate_2 differs from FortiGate_1 in that three interfaces are defined instead of two. The third interface is the local LAN that will be advertised into OSPF.

With the exception of creating the loopback interface, OSPF for this example can all be configured in either the web-based manager or CLI.

Creating the loopback interface

A loopback interface can be configured in the CLI only. For example, if the interface will have an IP address of 10.0.0.2, you would enter:

config system interface edit lback1 set vdom root

set ip 10.0.0.2 255.255.255.255 set type loopback

end

The loopback addresses on the two FortiGate units must be different. For example, set the FortiGate 1 loopback to 10.0.0.1 and the FortiGate 2 loopback to 10.0.0.2.

Configuring OSPF area and interfaces – web-based manager

1. On FortiGate_2, go to Network > OSPF.
2. Complete the following.

3. For Networks, select Create New.
4. Enter the following information for the loopback interface:

5. For Networks, select Create New.
6. Enter the following information for the tunnel interface:

7. For Networks, select Create New.
8. Enter the following information for the local LAN interface:

9. Select Apply.

Configuring OSPF area and interfaces – CLI

If for example, your loopback interface is 10.0.0.2, your tunnel ends are on the 10.1.1.0/24 network, your local LAN is 10.31.101.0/24, and your virtual IPsec interface is named tunnel_wan1, you would enter:

config router ospf set router-id 10.0.0.2 config area edit 0.0.0.0

end config network edit 1 set prefix 10.1.1.0 255.255.255.0

next edit 2 set prefix 10.31.101.0 255.255.255.0

next edit 2

Creating a redundant configuration

set prefix 10.0.0.2 255.255.255.255

end

config ospf-interface edit ospf_wan1 set interface tunnel_wan1 set network-type point-to-point

end

end

Creating a redundant configuration

You can improve the reliability of the OSPF over IPsec configuration described in the previous section by adding a second IPsec tunnel to use if the default one goes down. Redundancy in this case is not controlled by the IPsec VPN configuration but by the OSPF routing protocol.

To do this you:

• Create a second route-based IPsec tunnel on a different interface and define tunnel end addresses for it.
• Add the tunnel network as part of the OSPF network and define the virtual IPsec interface as an additional OSPF interface.
• Set the OSPF cost for the added OSPF interface to be significantly higher than the cost of the default route.

Adding the second IPsec tunnel

The configuration is the same as in Configuring the IPsec VPN on page 198, but the interface and addresses will be different. Ideally, the network interface you use is connected to a different Internet service provider for added redundancy.

When adding the second tunnel to the OSPF network, choose another unused subnet for the tunnel ends, 10.1.2.1 and 10.1.2.2 for example.

Adding the OSPF interface

OSPF uses the metric called cost when determining the best route, with lower costs being preferred. Up to now in this example, only the default cost of 10 has been used. Cost can be set only in the CLI.

The new IPsec tunnel will have its OSPF cost set higher than that of the default tunnel to ensure that it is only used if the first tunnel goes down. The new tunnel could be set to a cost of 200 compared to the default cost is 10. Such a large difference in cost will ensure this new tunnel will only be used as a last resort.

If the new tunnel is called tunnel_wan2, you would enter the following on both FortiGate units:

config router ospf config ospf-interface edit ospf_wan2 set cost 200 set interface tunnel_wan2 set network-type point-to-point

end end

Redundant OSPF routing over IPsec

This example sets up redundant secure communication between two remote networks using an Open Shortest Path First (OSPF) VPN connection. In this example, the HQ FortiGate unit will be called FortiGate 1 and the Branch FortiGate unit will be called FortiGate 2.

The steps include:

1. Creating redundant IPsec tunnels on FortiGate 1.
2. Configuring IP addresses and OSPF on FortiGate 1.
3. Configuring firewall addresses on FortiGate 1.
4. Configuring security policies on FortiGate 1.
5. Creating redundant IPsec tunnels for FortiGate 2.
6. Configuring IP addresses and OSPF on FortiGate 2.
7. Configuring firewall addresses on FortiGate 2.
8. Configuring security policies on FortiGate 2.

Creating redundant IPsec tunnels on FortiGate 1

1. Go to VPN > IPsec Tunnels.
2. Select Create New, name the primary tunnel and select Custom VPN Tunnel (No Template). Set the following:

4. Go to VPN > IPsec Tunnels.
5. Select Create New, name the secondary tunnel and select Custom VPN Tunnel (No Template).
6. Set the following:

Configuring IP addresses and OSPF on FortiGate 1

1. Go to Network > Interfaces.
2. Select the arrow for wan1 to expand the list.

Redundant OSPF routing over

3. Edit the primary tunnel interface and create IP addresses.

4. Select the arrow for wan2 to expand the list.
5. Edit the secondary tunnel interface and create IP addresses.

6. Go to Network > OSPF and enter the Router ID for FortiGate 1.
7. Select Create New in the Area
8. Add the backbone area of 0.0.0.
9. Select Create New in the Networks
10. Create the networks and select Area 0.0.0.0 for each one.
11. Select Create New in the Interfaces
12. Create primary and secondary tunnel interfaces.
13. Set a Cost of 10 for the primary interface and 100 for the secondary interface.

Configuring firewall addresses on FortiGate 1

1. Go to Policy & Objects > Addresses.
2. Create/Edit the subnets behind FortiGate 1 and FortiGate 2.
3. Create/Edit the primary and secondary interfaces of FortiGate 2.

Configuring security policies on FortiGate 1

1. Go to Policy & Objects > IPv4 Policy.
2. Create the four security policies required for both FortiGate 1’s primary and secondary interfaces to connect to FortiGate 2’s primary and secondary interfaces.

Creating redundant IPsec tunnels on FortiGate 2

1. Go to VPN > IPsec Tunnels.
2. Select Create New, name the primary tunnel and select Custom VPN Tunnel (No Template). Set the following:

Redundant OSPF routing over IPsec

4. Go to VPN > IPsec Tunnels.
5. Select Create New, name the secondary tunnel and select Custom VPN Tunnel (No Template).
6. Set the following:

Configuring IP addresses and OSPF on FortiGate 1

1. Go to Network > Interfaces.
2. Select the arrow for wan1 to expand the list.
3. Edit the primary tunnel interface and create IP addresses.

4. Select the arrow for wan2 to expand the list.
5. Edit the secondary tunnel interface and create IP addresses.

6. Go to Network > OSPF and enter the Router ID for FortiGate 2.
7. Select Create New in the Area
8. Add the backbone area of 0.0.0.
9. Select Create New in the Networks
10. Create the networks and select Area 0.0.0.0 for each one.
11. Select Create New in the Interfaces
12. Create primary and secondary tunnel interfaces.
13. Set a Cost of 10 for the primary interface and 100 for the secondary interface.

Configuring firewall addresses on FortiGate 2

1. Go to Policy & Objects > Addresses.
2. Create/Edit the subnets behind FortiGate 1 and FortiGate 2.
3. Create/Edit the primary and secondary interfaces of FortiGate 2.

Redundant OSPF routing over

Configuring security policies on FortiGate 2

1. Go to Policy & Objects > IPv4 Policy.
2. Create the four security policies required for both FortiGate 2’s primary and secondary interfaces to connect to FortiGate 1’s primary and secondary interfaces.

Results

1. Go to Monitor > IPsec Monitor to verify the statuses of both the primary and secondary IPsec VPN tunnels on FortiGate 1 and FortiGate 2.
2. Go to Monitor > Routing Monitor. Monitor to verify the routing table on FortiGate 1 and FortiGate 2. Type OSPF for the Type and select Apply Filter to verify the OSPF route.
3. Verify that traffic flows via the primary tunnel:
   • From a PC1 set to IP:10.20.1.100 behind FortiGate 1, run a tracert to a PC2 set to IP address 10.21.1.00 behind FortiGate 2 and vise versa.
   • From PC1, you should see that the traffic goes through 10.1.1.2 which is the primary tunnel interface IP set on FortiGate 2.
   • From PC2, you should see the traffic goes through 10.1.1.1 which is the primary tunnel interface IP set on FortiGate 1.
4. The VPN network between the two OSPF networks uses the primary VPN connection. Disconnect the wan1 interface and confirm that the secondary tunnel will be used automatically to maintain a secure connection.
5. Verify the IPsec VPN tunnel statuses on FortiGate 1 and FortiGate 2. Both FortiGates should show that primary tunnel is DOWN and secondary tunnel is UP.
6. Go to Monitor > IPsec Monitor to verify the status.
7. Verify the routing table on FortiGate 1 and FortiGate 2.

The secondary OSPF route (with cost = 100) appears on both FortiGate units.

8. Go to Monitor > Routing Monitor. Type OSPF for the Type and select Apply Filter to verify OSPF route.
9. Verify that traffic flows via the secondary tunnel:
   • From a PC1 set to IP:10.20.1.100 behind FortiGate 1, run a tracert to a PC2 set to IP:10.21.1.100 behind FortiGate 2 and vice versa.
   • From PC1, you should see that the traffic goes through 10.2.1.2 which is the secondary tunnel interface IP set on FortiGate 2.
   • From PC2, you should see the traffic goes through 10.2.1.1 which is the secondary tunnel interface IP set on FortiGate 1.

OSPF over dynamic IPsec

The following example shows how to create a dynamic IPsec VPN tunnel that allows OSPF.

Configuring IPsec on FortiGate 1

1. Go to Dashboard and enter the CLI Console widget 2. Create phase 1:

config vpn ipsec phase1-interface edit “dial-up” set type dynamic set interface “wan1” set mode-cfg enable set proposal 3des-sha1 set add-route disable set ipv4-start-ip 10.10.101.0 set ipv4-end-ip 10.10.101.255 set psksecret

next

end

3. Create phase 2:

config vpn ipsec phase2-interface edit “dial-up-p2” set phase1name “dial-up” set proposal 3des-sha1 aes128-sha1

next

end

Configuring OSPF on FortiGate 1

1. Go to Dashboard and enter the CLI Console
2. Create OSPF route.

config router ospf set router-id 172.20.120.22 config area edit 0.0.0.0 next

end config network edit 1 set prefix 10.10.101.0 255.255.255.0

next

end

config redistribute “connected” set status enable

end

config redistribute “static” set status enable

end

end

OSPF over dynamic

Adding policies on FortiGate 1

1. Go to Policy & Objects > IPv4 Policy and create a policy allowing OSPF traffic from dial-up to port5.
2. Go to Policy & Objects > IPv4 Policy and create a policy allowing OSPF traffic from port5 to dial-up

Configuring IPsec on FortiGate 2

1. Go to Dashboard and enter the CLI Console widget 2. Create phase 1:

config vpn ipsec phase1-interface edit “dial-up-client” set interface “wan1” set mode-cfg enable set proposal 3des-sha1 set add-route disable set remote-gw 172.20.120.22 set psksecret

next

end

3. Create phase 2:

config vpn ipsec phase2-interface edit “dial-up-client” set phase1name “dial-up-client” set proposal 3des-sha1 aes128-sha1 set auto-negotiate enable

next

end

Configuring OSPF on FortiGate 2

1. Go to Dashboard and enter the CLI Console
2. Create OSPF route.

config router ospf set router-id 172.20.120.15 config area edit 0.0.0.0 next

end config network edit 1 set prefix 10.10.101.0 255.255.255.0

next

end

config redistribute “connected” set status enable

end

config redistribute “static” set status enable

end

end

OSPF over dynamic IPsec

Adding policies on FortiGate 2

1. Go to Policy & Objects > IPv4 Policy and create a policy allowing OSPF traffic from dial-up-client to port5.
2. Go to Policy & Objects > IPv4 Policy and create a policy allowing OSPF traffic from port5 to dial-up-client

Verifying the tunnel is up

Go to Monitor > IPsec Monitor to verify that the tunnel is Up.

Results

1. From FortiGate 1, go to Monitor > Routing Monitor and verify that routes from FortiGate 2 were successfully advertised to FortiGate 1 via OSPF.
2. From FortiGate 1, go to Dashboard. Enter the CLI Console widget and type this command to verify OSPF neighbors:

get router info ospf neighbor

OSPF process 0:

Neighbor      ID Pri State Dead  Time     Address Interface

172.20.120.25 1  Full  /     –   00:00:34 10.10.101.1  dial-up_0

3. From FortiGate 2, go to Monitor > Routing Monitor and verify that routes from FortiGate 1 were successfully advertised to FortiGate 2 via OSPF.
4. From FortiGate 2, go to Dashboard. Enter the CLI Console widget and type this command to verify OSPF neighbors:

get router info ospf neighbor

OSPF process 0:

Neighbor      ID Pri State Dead  Time     Address     Interface

172.20.120.22 1  Full  /     –   00:00:30 10.10.101.2  dial-up_client

BGP over dynamic IPsec

The following example shows how to create a dynamic IPsec VPN tunnel that allows BGP.

Configuring IPsec on FortiGate 1

1. Go to Policy & Objects > Addresses and select create new Address.

2. Create an Address Group.

3. Go to Dashboard and enter the CLI Console widget.
4. Create phase 1:

config vpn ipsec phase1-interface edit Dialup set type dynamic set interface wan1 set mode aggressive set peertype one set mode-cfg enable set proposal 3des-sha1 aes128-sha1 set peerid dial set assign-ip disable set psksecret

next

end

5. Create phase 2:

config vpn ipsec phase2-interface edit dial_p2 set phase1name Dialup set proposal 3des-sha1 aes128-sha1 set src-addr-type name set dst-addr-type name set src-name all set dst-name VPN_DST next

BGP over dynamic IPsec

end

Configuring BGP on FortiGate 1

1. Go to Network > Interfaces and create a Loopback interface.
2. Set IP/Network Mask to 20.20.20/255.255.255.255.
3. Go to Dashboard and enter the CLI Console widget.
4. Create a BGP route.

config router bgp set as 100 set router-id 1.1.1.1 config neighbor edit 10.10.10.10 set ebgp-enforce-multihop enable set remote-as 200 set update-source loop

next

end

config redistribute connected set status enable

end

end

Adding policies on FortiGate 1

1. Go to Policy & Objects > IPv4 Policy and create a policy allowing BGP traffic from Dialup to loop interfaces. 2. Go to Policy & Objects > IPv4 Policy and create a policy allowing BGP traffic from loop to Dialup interfaces.

Configuring IPsec on FortiGate 2

1. Go to Dashboard and enter the CLI Console widget.
2. Create phase 1:

config vpn ipsec phase1-interface edit Dialup set interface wan1 set mode aggressive set mode-cfg enable

set proposal 3des-sha1 aes128-sha1 set localid dial set remote-gw 172.20.120.22 set assign-ip disable set psksecret

next

end

3. Create phase 2:

config vpn ipsec phase2-interface edit dial_p2 set phase1name Dialup

set proposal 3des-sha1 aes128-sha1 set keepalive enable

next end

BGP over dynamic IPsec

Configuring BGP on FortiGate 2

1. Go to Network > Interfaces and create a Loopback interface.
2. Set IP/Network Mask to 10.10.10/255.255.255.255.
3. Go to Dashboard and enter the CLI Console
4. Create a BGP route.

config router bgp set as 200 set router-id 1.1.1.2 config neighbor edit 20.20.20.20 set ebgp-enforce-multihop enable set remote-as 100 set update-source loop

next

end

config redistribute connected set status enable

end

end

Adding policies on FortiGate 2

1. Go to Policy & Objects > IPv4 Policy and create a policy allowing BGP traffic from Dialup to loop interfaces. 2. Go to Policy & Objects > IPv4 Policy and create a policy allowing BGP traffic from loop to Dialup interfaces.

Adding a static route on FortiGate 2

Go to Network > Static Routes and add a route to the remote Loopback interface via Dialup interface.

Verifying the tunnel is up

Go to Monitor > IPsec Monitor to verify that the tunnel is Up.

Results

1. From FortiGate 1, go to Monitor > Routing Monitor and verify that routes from FortiGate 2 were successfully advertised to FortiGate 1 via BGP.
2. From FortiGate 1, go to Dashboard.
3. Enter the CLI Console widget and type this command to verify BGP neighbors:

get router info bgp summary

BGP over dynamic IPsec

4. From FortiGate 2, go to Monitor > Routing Monitor and verify that routes from FortiGate 1 were successfully advertised to FortiGate 2 via BGP.
5. From FortiGate 2, go to Dashboard.
6. Enter the CLI Console widget and type this command to verify BGP neighbors:

get router info bgp summary

IPsec Auto-Discovery VPN (ADVPN)

Consider a company that wants to provide direct secure (IPsec) connections between all of its offices in New York, Chicago, Greenwich, London, Paris, Frankfurt, Tokyo, Shanghai, and Hong Kong.

A straightforward solution is to create a full mesh of connections such that every site has eight IPsec configurations, one for each of the other sites.  If there were ninety sites, that could still be done but now the configuration is becoming tedious, since every time a new site is added, N-1 other sites have to have their configuration updated.

An efficient and secure alternative is IPsec Auto-Discovery VPN (ADVPN), which allows a minimum amount of configuration per site but still allows direct IPsec connections to be made between every site. RF C 7018 essentially describes this problem, along with some requirements for candidate solutions.

The ADVPN solution involves partitioning the sites into spokes and hubs such that a spoke has to have enough IPsec configuration to enable it to connect to at least one hub.  A hub does not have specific configuration for each spoke, so the amount of configuration does not grow with the number of spokes that are connected to that hub.  A hub to hub connection would typically involve both hubs having configuration for each other.

So, one possible partition for the original nine sites would be that Chicago and Greenwich would be spokes for the New York hub, Paris and Frankfurt would be spokes for the London hub, and Tokyo and Hong Kong would be spokes for the Shanghai hub:

Once a spoke has established a connection to its hub then initially IPsec traffic to another site transits via one or more hubs.  For example, traffic from Chicago to Hong Kong would transit via the New York and Shanghai hubs.  This transit traffic then triggers an attempt to create a more direct connection.

In FortiOS:

• Direct connections are only created between the two endpoints that want to exchange traffic (e.g. Chicago and Hong Kong); we do not create intermediate connections (say Chicago to Shanghai, or New York to Hong Kong) as a side-effect.
• Learning the peer subnets is done via a dynamic routing protocol running over the IPsec connections.
• Negotiation of the direct connections is done via IKE. l Both PSK and certificate authentication is supported.

Example ADVPN configuration

Since dynamic routing with IPsec under FortiOS requires that an interface have an IP address, then for every site a unique IP address from some unused range is allocated.  For example we’ll assume that 10.100.0.0/16 is unused and so assign the IP addresses:

We’ll assume that each site has one or more subnets that it protects that it wants to make available to the peers.  For the purposes of exposition we’ll assume there is only one subnet per site and they are allocated as:

Our example network topology now looks like this:

Example ADVPN configuration                                                                            IPsec Auto-Discovery VPN (ADVPN)

The configuraton in Chicago would be as follows:

config vpn ipsec phase1-interface edit “New York” set type static set interface wan1

set remote-gw <New-York-IP-address> set psk <New-York-PSK> set auto-discovery-receiver enable

next

end

The attribute auto-discovery-receiver indicates that this IPsec tunnel wishes to participate in an autodiscovery VPN.  The IPsec interface would then have its IP assigned according to the Chicago address:

config system interface edit “New York” set ip 10.100.0.4/32 set remote-ip 10.100.0.1

next

end

RIP (for simplicity, you could use OSPF or BGP) is then configured to run on the IPsec interface and on the Chicago subnet (you could use redistribute connected, but we’ll allow for the fact that there may be other subnets learned from another router on the 10.0.4.0/24 subnet):

config router rip

edit 1 set prefix 10.100.0.0/16

next edit 2 set prefix 10.0.4.0/24

next

end

Other than the firewall policy and a minimal phase 2 configuration, this concludes the configuration for Chicago.  Each spoke would have a similar configuration.

The New York hub would have a dynamic phase 1 for its spoke connections, and two static phase 1s for its connections to the other hubs:

config vpn ipsec phase1-interface edit “Spokes” set type dynamic set interface wan1 set psk <New-York-PSK> set auto-discovery-sender enable set auto-discovery-psk enable set add-route disable

next edit “London” set type static set interface wan1 set psk <New-York-London-PSK> set auto-discovery-forwarder enable

next edit “Shanghai” set type static set interface wan1 set psk <New-York-Shanghai-PSK> set auto-discovery-forwarder enable

next

end

The ‘Spokes’ connection has set auto-discovery-sender enable to indicate that when IPsec traffic transits the hub it should optionally generate a message to the initiator of the traffic to indicate that it could perhaps establish a more direct connection.  The set add-route disable ensures that IKE does not automatically add a route back over the spoke and instead leaves routing to a separately configured routing protocol.

The two inter-hub connections have set auto-discovery-forwarder enable to indicate that these connections can participate in the auto-discovery process.  The interface IP addresses are assigned: config system interface edit “Spokes” set ip 10.100.0.1/32 set remote-ip 10.100.0.254

next edit “London” set ip 10.100.0.1/32 set remote-ip 10.100.0.2

next edit “London” set ip 10.100.0.1/32

Example ADVPN configuration                                                                            IPsec Auto-Discovery VPN (ADVPN)

set remote-ip 10.100.0.3

next

end

Following this, RIP is enabled on the relevant interfaces: config router rip edit 1 set prefix 10.100.0.0/16

next edit 2 set prefix 10.0.1.0/24

next

end

A similar configuration would be used on the other two hubs.

Traffic flow and tunnel connection

With the configuration in place at all spokes and hubs, assuming all the spokes are connected to a hub, then

Chicago would learn (via RIP) that the route to the Hong Kong subnet 10.0.8.0/24 is via its “New York” interface.  If a device on the Chicago protected subnet (say 10.0.4.45) attempted to send traffic to the Hong Kong protected subnet (say 10.0.8.13) then it should flow over the New York interface to New York, which should then transmit it over the Shanghai tunnel to Shanghai, which should then send it over the dynamically negotiated Hong Kong tunnel to Hong Kong.

At the point when the traffic transits New York it should notice that the Chicago Spoke tunnel and the Shanghai tunnel have auto-discovery enabled, causing the New York hub to send a message via IKE to Chicago informing it that it may want to try and negotiate a direct connection for traffic from 10.0.4.45 to 10.0.8.13.

On receipt of this message, IKE on Chicago creates the (FortiOS-specific) IKE INFORMATIONAL SHORTCUTQUERY message which contains the Chicago public IP address, the source IP of the traffic (10.0.4.45), the desired destination IP (10.0.8.13), and the PSK that should be used to secure any direct tunnel (if certificates are confgured, it is assumed that they all share the same CA and so no additional authentication information is required).  This message is sent via IKE to New York since routing indicates that New York is the best route to 10.0.8.13.

On receipt of the IKE INFORMATIONAL query, New York checks its routing table to see who owns 10.0.8.13.  It finds that 10.0.8.13 should be routed via Shanghai, and since Shanghai is marked as an auto-discovery-forwarder then the query is forwarded.

Shanghai repeats the process, finds that 10.0.8.13 should be routed via its Hong Kong Spoke and so sends it to Hong Kong.  Hong Kong checks 10.0.8.13, finds that it owns the subnet, so it remembers the Chicago public IP address (and PSK) and creates an IKE INFORMATIONAL reply message containing its external IP address.  To work out where to send the IKE message, the FortiGate does a routing lookup for the original source IP

(10.0.4.45), determines that the message should be routed via its Shanghai tunnel and so sends the reply back to Shanghai.  The reply then makes its way back to Chicago following the reverse of the path that it used to arrive at Hong Kong.

When the reply makes it back to the Chicago initator then it now knows the IP address of the Hong Kong device.  Chicago now creates a new dynamic tunnel with the remote gateway as the Hong Kong public IP address and initiates an IKE negotiation  (the dynamic tunnel nameis auto-generated from the tunnel over which it performed the query; in this case it would be called ‘New York_0’).

This negotiation should succeed since Hong Kong is set up to expect an attempted negotiation from the Chicago public IP address.  Once the negotiation succeeds, RIP will start to run on the newly created tunnels at Chicago and Hong Kong.  This will update the routing on Chicago (and Hong Kong) so that the prefered route to 10.0.8.0 (10.0.4.0) is via the newly created tunnel rather than via the connection to New York (Shanghai).

Notes about ADVPN in FortiOS

• Auto-discovery is only supported by IKEv1.
• All Spokes must have an IP address that is routable from any other spoke; devices behind NAT are not currently supported.
• The feature requires the use of a dynamic routing protocol. There is no support for IKE handling routing.
• RIP is not a very scalable routing protocol. When there are more than a few spokes it would be advisable to use route summarization to avoid huge RIP updates.  Better yet, use BGP instead of RIP.
• It is assumed that spokes will not be used to transit other spoke traffic, for example: traffic from Chicago to Tokyo would not transit an existing Chicago to Hong Kong tunnel even though that has a shorter hop count than a route via New York and Shanghai.
• There is no facility to allow you to filter which traffic that transits the hub should trigger the message sent to the initiator suggesting it create a direct connection. Currently any and all traffic will trigger it.

Logging and monitoring

This section provides some general logging and monitoring procedures for VPNs. The following topics are included in this section:

Monitoring VPN connections

VPN event logs

Monitoring VPN connections

You can use the monitor to view activity on IPsec VPN tunnels and to start or stop those tunnels. The display provides a list of addresses, proxy IDs, and timeout information for all active tunnels.

Monitoring connections to remote peers

The list of tunnels provides information about VPN connections to remote peers that have static IP addresses or domain names. You can use this list to view status and IP addressing information for each tunnel configuration. You can also start and stop individual tunnels from the list.

To view the list of static-IP and dynamic-DNS tunnels go to Monitor > IPsec Monitor.

Monitoring dialup IPsec connections

The list of dialup tunnels provides information about the status of tunnels that have been established for dialup clients. The list displays the IP addresses of dialup clients and the names of all active tunnels. The number of tunnels shown in the list can change as dialup clients connect and disconnect.

To view the list of dialup tunnels go to Monitor > IPsec Monitor.

If you take down an active tunnel while a dialup client such as FortiClient is still connected, FortiClient will continue to show the tunnel connected and idle. The dialup client must disconnect before another tunnel can be initiated.

The list of dialup tunnels displays the following statistics:

• The Name column displays the name of the tunnel.
• The meaning of the value in the Remote gateway column changes, depending on the configuration of the network at the far end:
• When a FortiClient dialup client establishes a tunnel, the Remote gateway column displays either the public IP address and UDP port of the remote host device (on which the FortiClient Endpoint Security application is installed), or if a NAT device exists in front of the remote host, the Remote gateway column displays the public IP address and UDP port of the remote host.
• When a FortiGate dialup client establishes a tunnel, the Remote gateway column displays the public IP address and UDP port of the FortiGate dialup client.
• The Username column displays the peer ID, certificate name, or XAuth user name of the dialup client (if a peer ID, certificate name, or XAuth user name was assigned to the dialup client for authentication purposes).

Logging and monitoring                                                                                                                   VPN event logs

• The Timeout column displays the time before the next key exchange. The time is calculated by subtracting the time elapsed since the last key exchange from the keylife.
• The Proxy ID Source column displays the IP addresses of the hosts, servers, or private networks behind the FortiGate unit. A network range may be displayed if the source address in the security encryption policy was expressed as a range of IP addresses.
• The meaning of the value in the Proxy ID Destination column changes, depending on the configuration of the network at the far end:
• When a FortiClient dialup client establishes a tunnel:
• If VIP addresses are not used and the remote host connects to the Internet directly, the Proxy ID Destination field displays the public IP address of the Network Interface Card (NIC) in the remote host.
• If VIP addresses are not used and the remote host is behind a NAT device, the Proxy ID Destination field displays the private IP address of the NIC in the remote host.
• If VIP addresses were configured (manually or through FortiGate DHCP relay), the Proxy ID Destination field displays either the VIP address belonging to a FortiClient dialup client, or a subnet address from which VIP addresses were assigned.
• When a FortiGate dialup client establishes a tunnel, the Proxy ID Destination field displays the IP address of the remote private network.

VPN event logs

You can configure the FortiGate unit to log VPN events. For IPsec VPNs, Phase 1 and Phase 2 authentication and encryption events are logged. For information about how to interpret log messages, see the FortiGate Log Message Reference.

Logging VPN events

1. Go to Log & Report > Log Settings.
2. Verify that the VPN activity event option is selected.
3. Select Apply.

Viewing event logs

1. Go to Log & Report > VPN Events.
2. Select the Log location.

Sending tunnel statistics to FortiAnalyzer

By default, logged events include tunnel-up and tunnel-down status events. Other events, by default, will appear in the FortiAnalyzer report as “No Data Available”. More accurate results require logs with action=tunnelstats, which is used in generating reports on the FortiAnalyzer (rather than the tunnel-up and tunnel-down event logs). The FortiGate does not, by default, send tunnel-stats information.

To allow VPN tunnel-stats to be sent to FortiAnalyzer, configure the FortiGate unit as follows using the CLI:

config system settings set vpn-stats-log ipsec ssl set vpn-stats-period 300 end

Troubleshooting

This section contains tips to help you with some common challenges of IPsec VPNs.

A VPN connection has multiple stages that can be confirmed to ensure the connection is working properly. It is easiest to see if the final stage is successful first since if it is successful the other stages will be working properly. Otherwise, you will need to work back through the stages to see where the problem is located.

When a VPN connection is properly established, traffic will flow from one end to the other as if both ends were physically in the same place. If you can determine the connection is working properly then any problems are likely problems with your applications.

On some FortiGate units, such as the FortiGate 94D, you cannot ping over the IPsec tunnel without first setting a source-IP. In this scenario, you must assign an IP address to the virtual IPsec VPN interface. Anything sourced from the FortiGate going over the VPN will use this IP address.

If the egress/outgoing interface (determined by kernel route) has an IP address, then use the IP address of the egress/outgoing interface. Otherwise, use the IP address of the first interface from the interface list (that has an IP address).

The first diagnostic command worth running, in any IPsec VPN troubleshooting situation, is the following: diagnose vpn tunnel list

This command is very useful for gathering statistical data such as the number of packets encrypted versus decrypted, the number of bytes sent versus received, the SPI identifier, etc. This kind of information in the resulting output can make all the difference in determining the issue with the VPN.

Another appropriate diagnostic command worth trying is:

diagnose debug flow

This command will inform you of any lack of firewall policy, lack of forwarding route, and of policy ordering issues.

The following is a list of such potential issues. Bear in mind that the troubleshooting suggestions below are not exhaustive, and may not reflect your network topology.

The options to configure policy-based IPsec VPN are unavailable.

Go to System > Feature Visibility. Select Show More and turn on Policy-based IPsec VPN.

The VPN connection attempt fails.

If your VPN fails to connect, check the following:

• Ensure that the pre-shared keys match exactly (see The pre-shared key does not match (PSK mismatch error). below).
• Ensure that both ends use the same P1 and P2 proposal settings (seeThe SA proposals do not match (SA proposal mismatch). below).
• Ensure that you have allowed inbound and outbound traffic for all necessary network services, especially if services such as DNS or DHCP are having problems.
• Check that a static route has been configured properly to allow routing of VPN traffic.
• Ensure that your FortiGate unit is in NAT/Route mode, rather than Transparent.

• Check your NAT settings, enabling NAT traversal in the Phase 1 configuration while disabling NAT in the security policy. You might need to pin the PAT/NAT session table, or use some of kind of NAT-T keepalive to avoid the expiration of your PAT/NAT translation.
• Ensure that both ends of the VPN tunnel are using Main mode, unless multiple dial-up tunnels are being used.
• If you have multiple dial-up IPsec VPNs, ensure that the peer ID is configured properly on the FortiGate and that clients have specified the correct local ID. Furthermore, in circumstances where multiple remote dialup VPN tunnels exist, each tunnel must have a peer ID set.
• If you are using FortiClient, ensure that your version is compatible with the FortiGate firmware by reading the FortiOS Release Notes.
• If you are using Perfect Forward Secrecy (PFS), ensure that it is used on both peers. You can use the diagnose vpn tunnel list command to troubleshoot this.
• Ensure that the Quick Mode selectors are correctly configured. If part of the setup currently uses firewall addresses or address groups, try changing it to either specify the IP addresses or use an expanded address range. This is especially useful if the remote endpoint is not a FortiGate device.
• If XAUTH is enabled, ensure that the settings are the same for both ends, and that the FortiGate unit is set to Enable as Server.
• Check IPsec VPN Maximum Transmission Unit (MTU) size. A 1500 byte MTU is going to exceed the overhead of the ESP-header, including the additional ip_header,etc. You can use the diagnose vpn tunnel list command to troubleshoot this.
• If your FortiGate unit is behind a NAT device, such as a router, configure port forwarding for UDP ports 500 and 4500.
• Remove any Phase 1 or Phase 2 configurations that are not in use. If a duplicate instance of the VPN tunnel appears on the IPsec Monitor, reboot your FortiGate unit to try and clear the entry.

If you are still unable to connect to the VPN tunnel, run the following diagnostic command in the CLI: diagnose debug application ike -1 diagnose debug enable

The resulting output may indicate where the problem is occurring. When you are finished, disable the diagnostics by using the following command:

diagnose debug reset diagnose debug disable

The VPN tunnel goes down frequently.

If your VPN tunnel goes down often, check the Phase 2 settings and either increase the Keylife value or enable Autokey Keep Alive.

The pre-shared key does not match (PSK mismatch error).

It is possible to identify a PSK mismatch using the following combination of CLI commands:

diag vpn ike log filter name <phase1-name> diag debug app ike -1 diag debug enable

This will provide you with clues as to any PSK or other proposal issues. If it is a PSK mismatch, you should see something similar to the following output:

ike 0:TRX:322: PSK auth failed: probable pre-shared key mismatch ike Negotiate SA Error:

The SA proposals do not match (SA proposal mismatch).

The most common problem with IPsec VPN tunnels is a mismatch between the proposals offered between each party. Without a match and proposal agreement, Phase 1 can never establish. Use the following command to show the proposals presented by both parties.

diag debug app ike -1 diag debug enable

The resulting output should include something similar to the following, where blue represents the remote VPN device, and green represents the local FortiGate. responder received SA_INIT msg incoming proposal:

proposal id = 1:

protocol = IKEv2: encapsulation = IKEv2/none type=ENCR, val=AES_CBC (key_len = 256) type=INTEGR, val=AUTH_HMAC_SHA_96 type=PRF, val=PRF_HMAC_SHA type=DH_GROUP, val=1536. proposal id = 2:

protocol = IKEv2: encapsulation = IKEv2/none type=ENCR, val=3DES_CBC

type=INTEGR, val=AUTH_HMAC_SHA_2_256_128 type=PRF, val=PRF_HMAC_SHA2_256 type=DH_GROUP, val=1536. proposal id = 1:

protocol = IKEv2: encapsulation = IKEv2/none type=ENCR, val=AES_CBC (key_len = 128) type=INTEGR, val=AUTH_HMAC_SHA_96 type=PRF, val=PRF_HMAC_SHA type=DH_GROUP, val=1536.

Pre-existing IPsec VPN tunnels need to be cleared.

Should you need to clear an IKE gateway, use the following commands:

diagnose vpn ike restart diagnose vpn ike gateway clear

LAN interface connection

To confirm whether a VPN connection over LAN interfaces has been configured correctly, issue a ping or traceroute command on the network behind the FortiGate unit to test the connection to a computer on the remote network. If the connection is properly configured, a VPN tunnel will be established automatically when the first data packet destined for the remote network is intercepted by the FortiGate unit.

If the ping or traceroute fail, it indicates a connection problem between the two ends of the tunnel. This may or may not indicate problems with the VPN tunnel. You can confirm this by going to Monitor > IPsec Monitor where you will be able to see your connection. A green arrow means the tunnel is up and currently processing traffic. A red arrow means the tunnel is not processing traffic, and this VPN connection has a problem.

If the connection has problems, see Troubleshooting VPN connections on page 226.

Dialup connection

A dialup VPN connection has additional steps. To confirm that a VPN between a local network and a dialup client has been configured correctly, at the dialup client, issue a ping command to test the connection to the local network. The VPN tunnel initializes when the dialup client attempts to connect.

If the ping or traceroute fail, it indicates a connection problem between the two ends of the tunnel. This may or may not indicate problems with the VPN tunnel, or dialup client. As with the LAN connection, confirm the VPN tunnel is established by checking Monitor > IPsec Monitor.

Troubleshooting VPN connections

If you have determined that your VPN connection is not working properly through Troubleshooting on page 223, the next step is to verify that you have a phase2 connection.

If traffic is not passing through the FortiGate unit as you expect, ensure the traffic does not contain IPcomp packets (IP protocol 108, RFC 3173). FortiGate units do not allow IPcomp packets, they compress packet payload, preventing it from being scanned.

Testing Phase 1 and 2 connections is a bit more difficult than testing the working VPN. This is because they require diagnose CLI commands. These commands are typically used by Fortinet customer support to discover more information about your FortiGate unit and its current configuration. Before you begin troubleshooting, you must:

• Configure FortiGate units on both ends for interface VPN
• Record the information in your VPN Phase 1 and Phase 2 configurations – for our example here the remote IP address is 10.11.101.10 and the names of the phases are Phase 1 and Phase 2
• Install a telnet or SSH client such as putty that allows logging of output
• Ensure that the admin interface supports your chosen connection protocol so you can connect to your FortiGate unit admin interface.

For this example, default values were used unless stated otherwise.

Obtaining diagnose information for the VPN connection – CLI

1. Log into the CLI as admin with the output being logged to a file.
2. Stop any diagnose debug sessions that are currently running with the CLI command diagnose debug disable

3. Clear any existing log-filters by running

diagnose vpn ike log-filter clear

4. Set the log-filter to the IP address of the remote computer (10.11.101.10). This filters out all VPN connections except ones to the IP address we are concerned with. The command is diagnose vpn ike log-filter dst-addr4 10.11.101.10.
5. Set up the commands to output the VPN handshaking. The commands are:

diagnose debug app ike 255 diagnose debug enable

6. Have the remote FortiGate initiate the VPN connection in the web-based manager by going to VPN > IPsec Tunnels and selecting Bring up.

This makes the remote FortiGate the initiator and the local FortiGate becomes the responder. Establishing the connection in this manner means the local FortiGate will have its configuration information as well as the information the remote computer sends. Having both sets of information locally makes it easier to troubleshoot your VPN connection.

7. Watch the screen for output, and after roughly 15 seconds enter the following CLI command to stop the output.

diagnose debug disable

8. If needed, save the log file of this output to a file on your local computer. Saving the output to a file can make it easier to search for a particular phrase, and is useful for comparisons.

Troubleshooting a Phase 1 VPN connection

Using the output from Obtaining diagnose information for the VPN connection – CLI on page 226, search for the word proposal in the output. It may occur once indicating a successful connection, or it will occur two or more times for an unsuccessful connection — there will be one proposal listed for each end of the tunnel and each possible combination in their settings. For example if 10.11.101.10 selected both Diffie-Hellman Groups 1 and 5, that would be at least 2 proposals set.

A successful negotiation proposal will look similar to

IPsec SA connect 26 10.12.101.10->10.11.101.10:500 config found created connection: 0x2f55860 26 10.12.101.10->10.11.101.10:500 IPsec SA connect 26 10.12.101.10->10.11.101.10:500 negotiating

no suitable ISAKMP SA, queuing quick-mode request and initiating ISAKMP SA negotiation initiator: main mode is sending 1st message…

cookie 3db6afe559e3df0f/0000000000000000 out [encryption]

sent IKE msg (ident-i1send): 10.12.101.10:500->10.11.101.10:500, len=264, id=3db6afe559e3df0f/0000000000000000

diaike 0: comes 10.12.101.1:500->10.11.101.1:500,ifindex=26….

Note the phrase “initiator: main mode is sending 1st message…” which shows you the

handshake between the ends of the tunnel is in progress. Initiator shows the remote unit is sending the first message.

Troubleshooting invalid ESP packets using Wireshark

The following section provides information to help debug an encryption key mismatch. The ESP packet invalid error is due to an encryption key mismatch after a VPN tunnel has been established. When an IPsec VPN tunnel is up, but traffic is not able to pass through the tunnel, Wireshark (or an equivalent program) can be used to determine whether there is an encryption mismatch. A mismatch could occur for many reasons, one of the most common is the instability of an ISP link (ADSL, Cable), or it could effectively be any device in the physical connection.

The following information is required to troubleshoot the problem.

• Take a packet sniffer trace on both FortiGates.
• Run the diag vpn tunnel list command a few times on both FortiGates when generating traffic that will pass through the tunnel.

In the following example, the error message was seen on the recipient FortiGate:

date=2010-12-28 time=18:19:35 devname=Kosad_VPN device_id=FG300B3910600118 log_ id=0101037132 type=event subtype=ipsec pri=critical vd=”root” msg=”IPsec ESP” action=”error” rem_ ip=180.87.33.2 loc_ip=121.133.8.18 rem_port=32528 loc_port=4500 out_intf=”port2″ cookies=”88d40f65d555ccaf/05464e20e4afc835″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_ group=”N/A” vpn_tunnel=”fortinet_0″ status=esp_error error_num=Invalid ESP packet detected (HMAC validation failed). spi=c32b09f7 seq=00000012

This is the output of the command diag vpn tunnel list on the FortiGate:

inet ver=1 serial=2 192.168.1.205:4500->121.133.8.18:4500 lgwy=dyn tun=intf mode=auto bound_if=4

proxyid_num=1 child_num=0 refcnt=7 ilast=0 olast=0

stat: rxp=41 txp=56 rxb=4920 txb=3360

dpd: mode=active on=1 idle=5000ms retry=3 count=0 seqno=696

natt: mode=keepalive draft=32 interval=10 remote_port=4500

proxyid=P2_60C_Fortinet proto=0 sa=1 ref=2 auto_negotiate=0 serial=1 src:

0:182.40.101.0/255.255.255.0:0

dst: 0:100.100.100.0/255.255.255.0:0

SA: ref=3 options=0000000d type=00 soft=0 mtu=1428 expire=1106 replaywin=0 seqno=15  life: type=01 bytes=0/0 timeout=1777/1800

dec: spi=29a26eb6 esp=3des key=24 bf25e69df90257f64c55dda4069f01834cd0382fe4866ff2

ah=sha1 key=20 38b2600170585d2dfa646caed5bc86d920aed7ff

enc: spi=c32b09f7 esp=3des key=24 0abd3c70032123c3369a6f225a385d30f0b2fb1cd9687ec8

ah=sha1 key=20 214d8e717306dffceec3760464b6e8edb436c6 This is the packet capture from the FortiGate:

How to verify if the original packet has been encrypted correctly

To verify, it is necessary to decrypt the ESP packet using Wireshark. Open the packet capture that is taken from initiator FortiGate using Wireshark. Go to Edit > Preferences, expand Protocol and look for ESP. Select  “Attempt to detect/decode encrypted ESP payloads“, and fill in the information for the encryption algorithm and the keys. This information can be obtained from the output of the command diag vpn tunnel list.

If the packet was encrypted correctly using the correct key, then the decryption will be successful and it will be possible to see the original package as shown below:

Repeat the decryption process for the packet capture from the recipient firewall. If the decryption failed using the same key, the packet may be corrupted and the interface should then be checked for CRC or packet errors

VPN troubleshooting tips

VPN troubleshooting tips

More in-depth VPN troubleshooting can be found in the Troubleshooting guide.

Attempting hardware offloading beyond SHA1

If you are trying to off-load VPN processing to a network processing unit (NPU), remember that only SHA1 authentication is supported. For high levels of authentication such as SHA256, SHA384, and SHA512 hardware offloading is not an option—all VPN processing must be done in software—unless using an NP6 (although the NP4lite variation also supports SHA256, SHA384, and SHA512).

Enable/disable IPsec ASIC-offloading

Much like NPU-offload in IKE phase1 configuration, you can enable or disable the usage of ASIC hardware for IPsec Diffie-Hellman key exchange and IPsec ESP traffic. By default hardware offloading is used. For debugging purposes, sometimes it is best for all the traffic to be processed by software. config sys global set ipsec-asic-offload [enable | disable]

end

Check Phase 1 proposal settings

Ensure that both sides have at least one Phase 1 proposal in common. Otherwise they will not connect. If there are many proposals in the list, this will slow down the negotiating of Phase 1. If its too slow, the connection may timeout before completing. If this happens, try removing some of the unused proposals.

NPU offloading is supported when the local gateway is a loopback interface.

Check your routing

If routing is not properly configured with an entry for the remote end of the VPN tunnel, traffic will not flow properly. You may need static routes on both ends of the tunnel. If routing is the problem, the proposal will likely setup properly but no traffic will flow.

Try enabling XAuth

If one end of an attempted VPN tunnel is using XAuth and the other end is not, the connection attempt will fail. The log messages for the attempted connection will not mention XAuth is the reason, but when connections are failing it is a good idea to ensure both ends have the same XAuth settings. If you do not know the other end’s settings enable or disable XAuth on your end to see if that is the problem.

General troubleshooting tips

Most connection failures are due to a configuration mismatch between the FortiGate unit and the remote peer. In general, begin troubleshooting an IPsec VPN connection failure as follows:

General troubleshooting tips

1. Ping the remote network or client to verify whether the connection is up. See General troubleshooting tips on page 229.
2. Traceroute the remote network or client. If DNS is working, you can use domain names. Otherwise use IP addresses.
3. Check the routing behind the dialup client. Routing problems may be affecting DHCP. If this appears to be the case, configure a DHCP relay service to enable DHCP requests to be relayed to a DHCP server on or behind the FortiGate server.
4. Verify the configuration of the FortiGate unit and the remote peer. Check the following IPsec parameters:
   • The mode setting for ID protection (main or aggressive) on both VPN peers must be identical.
   • The authentication method (preshared keys or certificates) used by the client must be supported on the FortiGate unit and configured properly.
   • If preshared keys are being used for authentication purposes, both VPN peers must have identical preshared keys.
   • The remote client must have at least one set of Phase 1 encryption, authentication, and Diffie-Hellman settings that match corresponding settings on the FortiGate unit.
   • Both VPN peers must have the same NAT traversal setting (enabled or disabled).
   • The remote client must have at least one set of Phase 2 encryption and authentication algorithm settings that match the corresponding settings on the FortiGate unit.
   • If you are using manual keys to establish a tunnel, the Remote SPI setting on the FortiGate unit must be identical to the Local SPI setting on the remote peer, and vise versa.
5. To correct the problem, see the following table.

VPN troubleshooting tips

L2TP and

A word about NAT devices

When a device with NAT capabilities is located between two VPN peers or a VPN peer and a dialup client, that device must be NAT traversal (NAT-T) compatible for encrypted traffic to pass through the NAT device. For more information, see Phase 1 parameters on page 52.

Troubleshooting L2TP and IPsec

This section describes some checks and tools you can use to resolve issues with L2TP-over-IPsec VPNs.

This section includes:

• Quick checks
• Mac OS X and L2TP
• Setting up logging
• Using the FortiGate unit debug commands

Quick checks

The table below is a list of common L2TP over IPsec VPN problems and the possible solutions.

Mac OS X and L2TP

FortiOS allows L2TP connections with empty AVP host names and therefore Mac OS X L2TP connections can connect to the FortiGate.

Prior to FortiOS 4.0 MR3, FortiOS refused L2TP connections with empty AVP host names in compliance with RFC 2661 and RFC 3931.

231

L2TP and

Setting up logging

L2TP logging must be enabled to record L2TP events. Alert email can be configured to report L2TP errors.

Configuring FortiGate logging for L2TP over IPsec

1. Go to Log & Report > Log Settings.
2. Select Event Log.
3. Select the VPN activity event check box.
4. Select Apply.

Viewing FortiGate logs

1. Go to Log & Report > VPN Events.
2. Select the Log location if required.
3. After each attempt to start the L2TP over IPsec VPN, select Refresh to view logged events.

Using the FortiGate unit debug commands

Viewing debug output for IKE and L2TP

1. Start an SSH or Telnet session to your FortiGate unit.
2. Enter the following CLI commands diagnose debug application ike -1 diagnose debug application l2tp -1 diagnose debug enable

3. Attempt to use the VPN and note the debug output in the SSH or Telnet session.
4. Enter the following command to reset debug settings to default:

diagnose debug reset

Using the packet sniffer

1. Start an SSH or Telnet session to your FortiGate unit.
2. Enter the following CLI command diagnose sniffer packet any icmp 4

3. Attempt to use the VPN and note the debug output.
4. Enter Ctrl-C to end sniffer operation.

Typical L2TP over IPsec session startup log entries – raw format

2010-01-11 16:39:58 log_id=0101037127 type=event subtype=ipsec pri=notice vd=”root” msg=”progress IPsec Phase 1″ action=”negotiate” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_ intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_ group=”N/A” vpn_tunnel=”dialup_p1″ status=success init=remote mode=main dir=outbound stage=1 role=responder result=OK

2010-01-11 16:39:58 log_id=0101037127 type=event subtype=ipsec pri=notice vd=”root” msg=”progress IPsec Phase 1″ action=”negotiate” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_ intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_

GRE over

group=”N/A” vpn_tunnel=”dialup_p1″ status=success init=remote mode=main dir=outbound stage=2 role=responder result=OK

2010-01-11 16:39:58 log_id=0101037127 type=event subtype=ipsec pri=notice vd=”root” msg=”progress IPsec Phase 1″ action=”negotiate” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_ intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_ group=”N/A” vpn_tunnel=”dialup_p1″ status=success init=remote mode=main dir=inbound stage=3 role=responder result=DONE

2010-01-11 16:39:58 log_id=0101037127 type=event subtype=ipsec pri=notice vd=”root” msg=”progress IPsec Phase 1″ action=”negotiate” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_ intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_ group=”N/A” vpn_tunnel=”dialup_p1_0″ status=success init=remote mode=main dir=outbound stage=3 role=responder result=DONE

2010-01-11 16:39:58 log_id=0101037129 type=event subtype=ipsec pri=notice vd=”root” msg=”progress IPsec Phase 2″ action=”negotiate” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_ intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_ group=”N/A” vpn_tunnel=”dialup_p1_0″ status=success init=remote mode=quick dir=outbound stage=1 role=responder result=OK

2010-01-11 16:39:58 log_id=0101037133 type=event subtype=ipsec pri=notice vd=”root” msg=”install IPsec SA” action=”install_sa” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_ intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_ group=”N/A” vpn_tunnel=”dialup_p1_0″ role=responder in_spi=61100fe2 out_spi=bd70fca1

2010-01-11 16:39:58 log_id=0101037139 type=event subtype=ipsec pri=notice vd=”root” msg=”IPsec Phase 2 status change” action=”phase2-up” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_group=”N/A” vpn_tunnel=”dialup_p1_0″ phase2_name=dialup_p2

2010-01-11 16:39:58 log_id=0101037138 type=event subtype=ipsec pri=notice vd=”root” msg=”IPsec connection status change” action=”tunnel-up” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_ user=”N/A” xauth_group=”N/A” vpn_tunnel=”dialup_p1_0″ tunnel_ip=172.20.120.151 tunnel_id=1552003005 tunnel_type=ipsec duration=0 sent=0 rcvd=0 next_stat=0 tunnel=dialup_p1_0

2010-01-11 16:39:58 log_id=0101037129 type=event subtype=ipsec pri=notice vd=”root” msg=”progress IPsec Phase 2″ action=”negotiate” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_ intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_ group=”N/A” vpn_tunnel=”dialup_p1_0″ status=success init=remote mode=quick dir=inbound stage=2 role=responder result=DONE

2010-01-11 16:39:58 log_id=0101037122 type=event subtype=ipsec pri=notice vd=”root” msg=”negotiate IPsec Phase 2″ action=”negotiate” rem_ip=172.20.120.151 loc_ip=172.20.120.141 rem_port=500 loc_port=500 out_ intf=”port1″ cookies=”5f6da1c0e4bbf680/d6a1009eb1dde780″ user=”N/A” group=”N/A” xauth_user=”N/A” xauth_ group=”N/A” vpn_tunnel=”dialup_p1_0″ status=success role=responder esp_transform=ESP_3DES esp_auth=HMAC_ SHA1

2010-01-11 16:39:58 log_id=0103031008 type=event subtype=ppp vd=root pri=information action=connect status=success msg=”Client 172.20.120.151 control connection started (id 805), assigned ip 192.168.0.50″

2010-01-11 16:39:58 log_id=0103029013 type=event subtype=ppp vd=root pri=notice pppd is started

2010-01-11 16:39:58 log_id=0103029002 type=event subtype=ppp vd=root pri=notice user=”user1″ local=172.20.120.141 remote=172.20.120.151 assigned=192.168.0.50 action=auth_success msg=”User ‘user1’ using l2tp with authentication protocol MSCHAP_V2, succeeded”

2010-01-11 16:39:58 log_id=0103031101 type=event subtype=ppp vd=root pri=information action=tunnel-up tunnel_id=1645784497 tunnel_type=l2tp remote_ip=172.20.120.151 tunnel_ip=192.168.0.50 user=”user1″ group=”L2TPusers” msg=”L2TP tunnel established”

Troubleshooting GRE over IPsec

This section describes some checks and tools you can use to resolve issues with the GRE-over-IPsec VPN. 233

GRE over

Quick checks

Here is a list of common problems and what to verify.

Setting up logging

Configuring FortiGate logging for IPsec

1. Go to Log & Report > Log Settings.
2. Select the Event Logging.
3. Select VPN activity event.
4. Select Apply.

Viewing FortiGate logs

1. Go to Log & Report > VPN Events.
2. Select the log storage type.
3. Select Refresh to view any logged events.

GRE tunnel keepalives

In the event that each GRE tunnel endpoint has keepalive enabled, firewall policies allowing GRE are required in both directions. The policy should be configured as follows (where the IP addresses and interface names are for example purposes only):

config firewall policy edit < id > set srcintf “gre” set dstintf “port1” set srcaddr “1.1.1.1”

GRE over

set dstaddr “2.2.2.2” set action accept set schedule “always” set service “GRE”

next

end

Cisco compatible keep-alive support for GRE

The FortiGate can send a GRE keepalive response to a Cisco device to detect a GRE tunnel. If it fails, it will remove any routes over the GRE interface.

Configuring keepalive query – CLI:

config system gre-tunnel edit <id> set keepalive-interval <value: 0-32767> set keepalive-failtimes <value: 1-255>

next

end

GRE tunnel with multicast traffic

If you want multicast traffic to traverse the GRE tunnel, you need to configure a multicast policy as well as enable multicast forwarding.

• To configure a multicast policy, use the config firewall multicast-policy
• To enable multicast forwarding, use the following commands:

config system settings set multicast-forward enable

end

Using diagnostic commands

There are some diagnostic commands that can provide useful information. When using diagnostic commands, it is best practice that you connect to the CLI using a terminal program, such as puTTY, that allows you to save output to a file. This will allow you to review the data later on at your own speed without worry about missed data as the diag output scrolls by.

Using the packet sniffer – CLI:

1. Enter the following CLI command:

diag sniff packet any icmp 4

2. Ping an address on the network behind the FortiGate unit from the network behind the Cisco router.

The output will show packets coming in from the GRE interface going out of the interface that connects to the protected network (LAN) and vice versa. For example:

114.124303 gre1 in 10.0.1.2 -> 10.11.101.10: icmp: echo request

114.124367 port2 out 10.0.1.2 -> 10.11.101.10: icmp: echo request

114.124466 port2 in 10.11.101.10 -> 10.0.1.2: icmp: echo reply

114.124476 gre1 out 10.11.101.10 -> 10.0.1.2: icmp: echo reply

235

GRE over

3. Enter CTRL-C to stop the sniffer.

Viewing debug output for IKE – CLI:

1. Enter the following CLI commands diagnose debug application ike -1 diagnose debug enable
2. Attempt to use the VPN or set up the VPN tunnel and note the debug output.
3. Enter CTRL-C to stop the debug output.
4. Enter the following command to reset debug settings to default:

diagnose debug reset

FortiGate Firewall Components

The FortiGate firewall is made up of a number of different components that are used to build an impressive list of features that have flexibility of scope and granularity of control that provide protection that is beyond that provided by the basic firewalls of the past.

Some of the components that FortiOS uses to build features are:

• Interfaces
• VLANs
• Soft Switches l Zones
• Predefined Addresses l IP address based l FQDN based l Geography based l Access Schedules l Authentication l Local User based l Authentication Server based (Active Directory, Radius, LDAP) l Device Based l Configureable Services l IPv4 and IPv6 protocol support

The features of FortiOS include but are not limited to:

• Security profiles, sometimes referred to as Unified Threat Management (UTM) or Next Generation Firewall

(NGFW) l Predefined firewall addresses (this includes IPv4 and IPv6, IP pools,. wildcard addresses and netmasks, and geography-based addresses)

• Monitoring traffic l Traffic shaping and per-IP traffic shaping (advanced) l Firewall schedules l Services (such as AOL, DHCP and FTP) l Logging traffic l Quality of Service (QoS) l Identity-based policies l Endpoint security