Interface used just for SMTP traffic

[Anthony.Herman]

I have two outside interfaces - I need all SMTP traffic to be on one and the other used for all other traffic. What is the best way to do this?

[Marvin Rhoads · Accepted solution]

If it's a router, the typical method used for such a requirement would be policy-based routing.

High level white paper on it.

Configuration Guide.

In your case the access-list match would be for traffic from your mail server(s) on port 25 (smtp).

[Anthony.Herman]

Thanks for the config. link