...sorry, my original description wasn't completely accurate. I was trying to describe a problem reported by a colleague.

I think the problem with the session IDs not being unique is whether it is possible for IIS to re-use a session ID allocated to another client?

Thanks,
Gary

Take a look at this KB article:

http://support.microsoft.com/?kbid=899918

Session IDs will be unique UNLESS you reboot the server and, even then, there is only a very very small chance that the same session ID will be used again.

--Stole this from a moderator

I will only tell you how to do it, not do it for you.
Unless, of course, you want to hire me to do work for you.