a-net links with b-net ( firewall's nat ) and c-net, c-net links Internet, all nets use public ipv4 addresses. a-net's users visit c-net's resources through M320's interface linking c-net( c-net's prefix), and others linking b-net by nat( default route).
Now the problem arises, if a-net's user provides services, other users outside a-net and c-net through c-net come to a-net, but return back through b-net, not c-net. this may cause some applications not in operation.
how can i resolve this come-and-go-not-same problem?
Message Edited by xuzhengwei on 09-02-2009 05:55 PM
Message Edited by xuzhengwei on 09-02-2009 05:57 PM
so I assume you want that entire traffic to net-a should come through net-b router (to avoid assymetric routing). I also assume that you run eBGP on net-b and net-c. Then you should advertise your net-a route with AS-path prepending done by net-c router (I do not entirely understand, are you running eBGP to net-b and net-c routers or are you running eBGP from net-b and net-c routers to SPs..) + use community which causes provider net-c to assign local preference value lower than the value they assign to the routes they receive from thier peers and upstream providers.