Issue with Storing Session

Sometimes, the session on your website can expire earlier than you expect. The followings are the steps you need to check:

1. In .Net, you cannot use authentication without session. The session ID can be transmitted with client either in a cookie, or in the page url. There is no need to choose between session and cookie, as the cookie actually holds the session id.

2. On the server, session data is stored either in memory (in process or outside process), or in database.

3. The cookie is encrypted using a key called the "machine key". By default, everytime the app pool is recycled, a new machine key is created and the session data that is in memory is lost. On a shared server, this results in the end of a session, since the cookie cannot be decrypted anymore.

The solution: Store a static machine key in the web.config of the web application.

Also, storing the session data in the database instead of memory (in proc) can be useful to preserve sessions.