I have a site up that has an odd behavior I'd like to correct. Whenever a submit button is pressed, even for logging in, the www part is dropped from the URL, and all subsequent pages are displayed sans www. The site appears to work correctly either way, but I'd still like for it to stop switching over. Is there a way I can fix that behavior, and if so, how?
It is an apache configuration issue. You must be redirecting the URL in one of the config files.
Not necessarily. There are three things that could be causing this:
* As you say, there's a redirect happening in the Apache config.
* Alternatively, the user could have uncommented the forced redirects in the .htaccess that ships with Drupal.
* Alternatively, the user could have set the $base_url in his settings.php to include the non-www version. Best solution here would NOT to define anything in the $base_url and let Drupal figure it out based on the request.