prevent $_SESSION vars from being on multiple domains on same server?

Question

I am in the process of planning for a series of websites that will all point to the same server and share the same back end code, but have different domain names, different content, and look completely different. Here is my issue, say a user visits one website and adds something to the cart, then visits the other website. (which is actually the same server just different domain pointing to it) I do not want the SESSION variables to travel across.

I am thinking one possible solution is to keep track of what domain they are requesting, and if that changes destroy the session, but the disadvantage there is if they go back, they will have lost everything. Is there a way to keep them all live but prevent them from going across domains? I hope this makes sense.

Thanks!

Answer 1

Sessions do not travel across domains.

Answer 2

Use this:

http://us2.php.net/manual/en/function.session-set-cookie-params.php