vbulletin: getting user ip behind a proxy

if vbulletin is behind a proxy, the ip of the user would be the ip of the proxy server instead of the ip of the user. Instead of hacking the includes/class_core.php file we can install the runkit extension, ie http://www.php.net/manual/en/runkit.installation.php

then create a plugin consisting of the following:


$vbulletin->ipaddress = $vbulletin->alt_ip;
runkit_constant_redefine('IPADDRESS', $vbulletin->ipaddress);