Description
This article describes how to configure multiple local-as on FortiGate with one as iBGP.
Scope
Though FortiGate support multiple local-as, but it fails in the case of the iBGP:
(using local-as value as remote-as in neighbour configuration level).
Solution
Configure the iBGP as the global BGP and use the set local-as command for eBGP neighbours.
In the above configuration, neighbour 192.168.1.1 is an iBGP neighbour while 192.168.2.2 is an eBGP neighbour with a different local-as '6500'.
Related article:
Technical Note: BGP multiple local-AS configuration and advertisement
