g1smd - 10:38 am on Aug 31, 2011 (gmt 0)

Since URLs are published on the web as links, you can't keep a URL secret. However, you can control access over what content that URL returns based on what was in the users HTTP request.

You could look at the referrer (which may be missing or spoofed) or you could look at the cookie data that you dropped on their browser on a previous page view (which could be spoofed, unless you take extra steps) or you could ask for a user name and password.