preventing annoying logouts when using multiple sites

UPDATE: i just had to add a conf_init() call before that line to get this working again. Odd.

Drupal 4.7 added a session_regenerate() call which makes it harder to stay logged into multiple sites on the same domain.That call is essential for preventing session fixation attacks, so I'd rather not comment it out, even on dev sites. My fix is to add the following line to bottom of settings.php

conf_init();
ini_set('session.name',  preg_replace("/[^a-z\d]/i", "", $GLOBALS['base_url']));

This line changes the session cookie's name from PHPSESSIONID to a name based on the name of your settings.php directory path. That path should be unique enough to prevent these cookie conflicts. The preg_replace() is there to strip out all non alphanumeric characters since those are invalid in a cookie name.

Also see Cannot stay logged in on more than one site on the same server