Single carrier multi-circuit asynchronous routing issue

Wed Jan 7 20:05:56 UTC 2009

* aaron.millisor at bright.net (Aaron Millisor) [Wed 07 Jan 2009, 20:53 CET]:
[..]
>If I were to prepend the network 1.1.1.0 to come in on 'sprint 1', but 
>have a route to 2.2.2.0 via 'sprint 2' so that traffic comes in on one 
>circuit but returns on the other, routing is broken. If I change my 
>route so that packets directed to 2.2.2.0 return on the same circuit 
>that the traffic is received on, everything works fine.

You might be running into uRPF (unicast reverse path forward 
verification).

	-- Niels.