Stumped on cookieless sessions

I am currently in development of a site that I wish to function regardless of whether or not the user has cookies enabled. I have it mirrored on a development box on the local LAN and a test box on the Internet. The local machine has RH6.1/PHP4.0, the test box RH6.2/PHP4.02. The problem I am having has me stumped. On the local box, shutting off cookies does not alter the functionality of the site. On the test box, sessions will not work unless cookies are enabled. After changing everything I could think of in the remote php.ini to the correct values, I finally copied the local php.ini to the remote machine, hoping to catch something I missed. No luck; they still don't work. Note that with cookies enabled, the remote box is properly saving sessions to /tmp (where it is told, for now). Why would it not work without cookies? Note also that I am manually appending SID to the url. Thanks, Ben