F5 loadbalancer and session timeout in ASP application

I don't think that a fallback persistence profile will help, as clients will probably already have a persistence record based on the cookie. In this case that change would have no effect.

I've just checked: the default idle timeout from the TCP profile is 300 seconds. If this service has a higher idle timeout, I can think about two solutions: x) get the application to send TCP keepalives regularly, or x) set the idle timeout value to, e.g. 1800 seconds (or higher) Probably the second solutions fits better for you :-)

Hope this helps, Manuel