We've seen a few questions about this lately, so I have compiled this brief list of vBSEO server requirements. In general, if your host will run your vBulletin install, it will most likely run vBSEO as well. Here's a quick outline:
vBSEO runs on most Windows/*nix/BSD webservers that support a rewrite module (mod_rewrite, isapi, etc), including
- IIS6 & IIS7
and possibly others (just ask, we may be able to provide a custom rule set)
As of vBSEO version 3.5.0 RC2, vBSEO REQUIRES php 5, preferably php 5.2.x or higher. If you are still on php4, you will need to use vbseo 3.3.2 (not compatible with vb4.x)
MySQL5 is preferred, but vbseo will work on lower versions, as outlined by vBulletin minimum requirements.
Depending on your traffic and DB size, you may need to increase certian settings on your server.
Depending on your configuration, you may need more memory of script time to execute certain scripts. If you are receiving "white pages" (or other blank, 500 errors), it is likely a memory limit issue. Raise it, restart the webserver and try again.
You may also need to alter other settings such as max_execution_time and other similiar settings. Contact your host if you are having issues with things like this.
Items such as mod_security and suhosin may cause conflicts with both vBSEO and vBulletin core scripts. In general, these software filters tend to do more harm than good. If you think you need a solution like this, you should look into a hardware firewall that is configured properly or move to a data center that has a better outside network firewall system.