IpbWiki Automatic Login when using subdomains

Go to your Invision Power Board Administration Control Panel
Click on the tabpage Tools & Settings
In the group "System Settings", choose "View all general settings"
Choose the Cookies item
Fill in the following values:
- Cookie domain: set this to your global domain, for instance if you run your wiki on wiki.ipbwiki.com and your forum on forum.ipbwiki.com, then the global domain is .ipbwiki.com
- Cookie name prefix: Enter a value such as forum or leave the box blank
- Cookie path: Set this to /