Help:CheckUser

The CheckUser extension allows a user with checkuser permission to check which IPs are used by a given username, and which usernames are used by a given IP.

Usage
The usual use of this feature is to check for blocked users coming back with multiple accounts. If you are having problems with these sorts of users on your wiki, feel free to contact Wikia's Community Team and ask for someone to check the IPs. You may be given details on whether two usernames are being used by the same person, or are editing under similar IPs. The exact IP of logged in users will only be given if the information is necessary in order to make a range block to deal with major vandalism. Please do not ask that CheckUser be run simply because you are curious about a user. It will only be run in the case of highly disruptive sock puppets, or major vandalism from a range of IPs. A private log is kept of all uses of this feature on each wiki.

Please note that the feature is not perfect. There will often be no clear way of knowing whether two usernames are operated by the same person. See the hints and tips section of the help page on Meta, which explains the difficulties associated with users who have using dynamic or proxy IPs. Data is not stored permanently, so if a user has not edited under a particular account for a long time, the feature might not list their edits in a search.