Tunneling IPv6 through IPsec VPN
A variation on the tunneling IPv6 through IPv4 is using an IPsec VPN tunnel between to FortiGate devices. FortiOS supports IPv6 over IPsec. In this sort of scenario, 2 networks using IPv6 behind FortiGate units are separated by the Internet, which uses IPv4. An IPsec VPN tunnel is created between the 2 FortiGate units and a tunnel is created over the IPv4 based Internet but the traffic in the tunnel is IPv6. This has the additional advantage of make the traffic secure as well.
For configuration information, see IPv6 IPsec VPN on page 1.
IPv6 support for GRE tunnels
You can use IPv6 addresses can be used at both ends of a GRE tunnel in the same way as with IPv4.
The configuration is similar to how you set up the tunnel for IPv4. However, when you configure the specific tunnel, you need to set the ip-version option to 6. This will enable IPv6-specific options for the tunnel.
CLI
config system gre-tunnel edit <name of tunnel> set ip-version 6 set remote-gw6 <IPv6 address of the remote gateway> set local-gw-6 <IPv6 address of the local gateway>
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