web pages stay active 3 minutes then places you on logon screen

Question

I have a C# 2010 web form application that I just deployed to a test server that is similar to the production server running iis 7. The entire website works fine but the screens only stay active for an inconsistent amount of time. The entire website throws you  back to the main logon screen. Thus can you tell me what kind of a setting for the entire web site and/or iis server that needs to be changed so the server and /or application does not throw you out to the logon page after being on the website for 5 minutes or less?