LTM, Routing, and Multiple Gateways 

Today Deb & Colin discuss the steps required to configure LTM to "source route" traffic (preferring a specific external next-hop gateway for connections originating on different internal VLANs) and to ensure return traffic uses the "correct" gateway when more than one is available.

The post contains all the configuration details and a b-e-a-u-tiful ASCII diagram from one of our favorite F5 Consultants, Mr. Denny Payne:  Source routing.