Extension:GlobalBlocking

The GlobalBlocking extension allows a user with the appropriate permissions to block an IP address or IP address range (but not accounts) on all wikis in a group sharing the same globalblocking database. It is intended to be used for combating severe cross-wiki vandalism and spam. Before revision 6899, IPv6 addresses were accepted by the block form, but the blocks were not effective and did not show up in the list of global blocks, unless the default schema of the global blocking database was changed (see below).

API
Two API modules are provided, one to (un)block users, and another to view existing global blocks. They are documented at Extension:GlobalBlocking/API

Usage
The following requires appropriate permissions, assigned by default to stewards, which by default can be added or removed by bureaucrats. To make a global block: To remove a global block: Blocks for X-Forwarded-For Header:
 * 1) Go to Special:GlobalBlock
 * 2) Enter the IPv4 address or range (up to /16) that you wish to block (or any IPv6 address or range up to /4 if you made the schema changes prescribed in the installation instructions section of this page or you have the latest revision), and decide if you want to only block anonymous users. To only block anonymous users, check the checkbox.
 * 3) Submit the form. The IP address or range is now globally blocked on your wikis that opt in to the global blocking. Account creation is blocked (even if you selected "anonymous users only": bug 40190), and the blocked IP or range cannot edit any associated user talk pages on any wiki affected and opted in to the global block. If Extension:AbuseFilter is installed, globally blocked IP addresses are prohibited from viewing the abuse log if the particular wiki is opted in to the block.
 * 1) Go to Special:GlobalBlockList and click "Remove a global block"
 * 2) Enter the IP address or range to unblock and the reason, and submit the form. The IP address or range is no longer globally blocked.
 * 1) The flag $wgGlobalBlockingBlockXFF, set to true by default, causes blocks to apply to all of the IP addresses in the XFF header. Set this flag to false to disable this feature. For more details, see bug 23343.