It happens that I run across customers who have what I define as an "asymetric routing" in their networks. Simply said, they have two gateways on the same IP subnet. The clients are configured to point at one gateway (i.e. 172.16.1.1) but there is another device (i.e. 172.16.1.2) which connects and routes to somewhere. Mostly I've seen this kind of setup when there are 2 different types of WAN connections: 1 internet connection and 1 corporate MPLS connection.
I'm personally not attracted by the above kind of network design: each subnet has to have one and only one gateway. From my point of view, the above scenario may create some issues for clients, because they send a packet to their default gateway (172.16.1.1) and those packets are then forwarded out the other router (172.16.1.2) and when they get replied to, they reach the client simply passing through 172.16.1.2. The clients would or should expect the reply packets come from 172.16.1.1, or am I wrong here?
I'd be happy to have your opinions and technical views of this issue.