We are not using snat for this paticular connection.
We have IP Forwarding turned on all ports.
When cutover to 9.x the webserver behind the F5 LTM reported that it lost connection to database we were addressing other issues and did not get a chance to address the issue. The application analyst for the change did not know the application well and we did not find out till afterwards it was database connectivity problem. When we failed back to 4.5.x the webserver was again able to talk to the database. The database connects on non stadard port (2125)and is not behind the F5. The F5 acts as a router.