I have 2 IIS 7.5 web servers that are set up in round robin DNS to mylab.com (servers are Web1 and Web2).
They are both running multiple .Net 4.0 sites and everything works okay except for after some time users are logged off. We've narrowed it down to users logging on one server then being passed to the other and not being logged in.
To remedy this I've tried setting up State servers using both Asp Session State and SQL Server session state, but nothing has helped.
I've made sure both sites on each server all have matching site ID's and I've also made sure the ASP.Net State Services is running and set to automatic. I'm not seeing any errors, no matter whether I try SQL or State session configuration in IIS Manager. Yet still I get logged out once I bounce from one server to another.