Debugging mysterious PHP requests

Question

Whenever I get a 404 our logout script is being called mysteriously. What should be happening is our custom ErrorDocument defined in the root .htaccess file should be redirecting to a static HTML page, without any external logout actions being initiated.

I'm using Zend Studio's debugger and at first everything goes as expected -- it serves up the 404. But immediately afterward a separate request is picked up by the debugger which calls the logout page.

I can't find out what is initiating this second request. I stepped through the entire request that serves up the 404 and there were no headers or redirects that would cause this to happen. It seems like something external may be going on here, but I can't locate it.

I've examined the php.ini and httpd.conf files for anything suspicious being initiated in the event of a 404 but with no luck. Any idea how I might debug the source of this second request for the logout page?

Answer 1

try to build some kind of tracking in the logout script. Try to track who calls is - if the request comes from the same client IP as 404 page request, or maybe there is a code somewhere in your app (e.g. file_get_contents()), where request is being generated from server itself (then 404 page request would have different IP compared to logout request, which comes after it)