Integrated IS-IS is an extended version of IS-IS that includes support for both IPv4 and IPv6. IPv4 and IPv6 interface addresses are determined by TLVs 132 and 232, respectively. The parameter responsible for IPv6 reachability is TLV 236. For more information on TLVs, see “Troubleshooting IS-IS”.

The FortiGate unit command config router isis is almost the same except that IPv6 addresses are used. Also, if you are going to use prefix or access lists with Integrated IS-IS, you must use the config router access-list6 or config prefix-list6 versions of those commands.

If you want to route IPv4 traffic over an IPv6 network, you can use the command config system ipv6-tunnel to configure the FortiGate unit to do this. The IPv6 interface is configured under config system interface. All subnets between the source and destination addresses must support IPv6. This command is not supported in Transparent mode.

For example, you want to set up a tunnel on the port1 interface starting at 2002:C0A8:3201:: on your local network and tunnel it to address 2002:A0A:A01:: where it will need access to an IPv4 network again. Use the following command:

The CLI commands associated with Integrated IS-IS include: