Request.UrlReferrer null?

Question

In an aspx C#.NET page (I am running framework v3.5), I need to know where the user came from since they cannot view pages without logging in. If I have page A

Answer 1

The problem could be related on how you redirect the user to some other page. Anyways, the referer url is nothing you should take as absolute rule - a client can fake it easily.