I've added this inside the system.web node of my web.config
<sessionState mode="InProc" timeout="600" />
but my sessions are timing out within 30 minutes.
is there something else I need to do to increase my session timeout length?
There is a forms authentication node in my web.config as well but I'm not using any authentication on the web site. The forms authentication has a timeout value of 2880...but again, I'm not doing any authentication at all...
but my sessions are timing out within 30 minutes.
I suspect it's IIS which is recycling the application pool after a certain time of inactivity. And since your sessions are stored in-memory their contents is wiped out of existence when the web server tears down the application domain.
Look at the properties of the application pool of your application in IIS. You will see that there are settings allowing to configure this. There are also conditions such as memory or CPU threshold limits when IIS might recycle your application pool. If you want durable sessions you need to make them out-of-proc (session state server or SQL).
