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Autoblock

Shortcut: WP:AUTOBLOCK  This page describes the autoblock feature.

An example of an autoblock causing collateral damage.

An autoblock is, as the name suggests, an automatic block of an IP address set by the MediaWiki software. Autoblocks are the result of an attempt to edit Wikipedia from an IP address recently used by a blocked user.

Each time a user edits Wikipedia, the IP address used to connect to the site is recorded by the MediaWiki software that powers Wikipedia. A log of IP addresses used by every user is kept privately, accessible only by users with checkuser access to the MediaWiki software. When a blocked user attempts to edit the site, the IP from which they are editing is "autoblocked," so that they may not make the same edit anonymously or under a different user name.

Unblocking an autoblocked user

Users who find themselves autoblocked accidentally should contact the administrator that issued the initial block and request an unblock, such as by sending them email with the "Email this user" option at that admin's userpage. Unblocks may also be requested in the #wikipedia IRC channel on freenode.

If a user is autoblocked, such as if a named user was unblocked, but their IP address is still autoblocked, an admin can clear the autoblock by:

• Reviewing the list at Special:IPBLockList, and searching for the user's account name. This is a case-sensitive search.
• Identifying the #xxxxx number that is associated. If searching on this number, be sure to include the "#"
• Unblocking the #xxxxx by clicking the "unblock" link

Note that once the autoblock is cleared, the user's account name will no longer appear in the list.

Messages

Sometimes the following terms will show up in a block message:

Autoblock enabled 

This means that the user that was blocked, also had their IP address blocked. The IP is not shown in the message, but they or any other users attempting to edit Wikipedia from that IP will be "autoblocked".

Autoblock disabled 

This means that when the user was blocked, only their username was blocked, but other users on the same IP are still free to edit.

How it works

When an autoblock occurs, users may be autoblocked as the result of a block on another user, who was probably using the same ISP. So a different user may end up blocked, even though they have personally done nothing wrong. This is referred to as "collateral damage". Example:

1. Admin Susan blocks User:Bort for 24 hours. Unknown to Susan, Bort uses AOL to edit Wikipedia, and an autoblock was enabled at the time of the block
2. User:Steven, who also uses AOL from home, and is currently assigned the IP address last used by Bort, signs on to Wikipedia
3. The MediaWiki software, detecting the use of the IP by Steven, and assuming it to be Bort, issues a 24 hour block on Steven, in admin Susan's name. Susan is not notified of the block.
4. Steven receives a "You have been blocked" message, doesn't understand what an autoblock is, and angrily demands to know why admin Susan has blocked him.
5. Steven tries to login from his work computer (which does not use AOL)
6. The MediaWiki software senses that Steven is trying to get around his block, and autoblocks his work IP as well
7. One of Steven's co-workers, who happens to use the same work IP, tries to access Wikipedia
8. The MediaWiki software senses the co-worker, and autoblocks them too, as well as any future IPs they may use
9. And so on...

It is important for users to understand that administrators do not set autoblocks; once they have blocked a user with autoblocking enabled, autoblocks are set by the MediaWiki software. Autoblocks do not appear in administrators' block logs, and the administrators are not notified of them. This is a necessary consequence of Wikipedia's privacy policy, to keep logged-in users' IP addresses private. So while the IP address responsible for each edit is recorded by the MediaWiki software, this cannot be accessed, even by administrators and even when the user is blocked.

The only circumstances in which a user may be associated with an IP address, are certain policy violations detailed by the checkuser policy; even then, access to the Checkuser tool is granted only to a small group of trusted users, not administrators in general.

Disabling autoblocking

When a block is issued, autoblocking is usually turned on by default, especially for common dynamic IP ranges, such as those used by AOL. A list of such automatically exempt IP ranges can be found at MediaWiki:Autoblock whitelist.

Administrators can disable autoblocking at the time of blocking a user, by unchecking the checkbox. Once an "enabled" block is placed, it can also be fixed by unblocking and re-blocking the user, but this should not be done unless absolutely necessary.

Automatic reset

There is an internal autoblock expiry time variable, which is set to 24 hours, meaning that autoblocks only last for 24 hours. However, in the case of dynamic IP pools (such as those used by AOL), this may affect hundreds of users before the block expires. So in the case of an indefinite block, autoblocks may continue to be set by the software, weeks or months after the initial block has been set. Older indefinite blocks, dating from before the autoblock exemption whitelist and the option to disable when blocking, may also trigger autoblocks. It is not uncommon to find autoblocks listed on Special:Ipblocklist, where the initial indefinite block was issued in 2003 or 2004!

Ipblocklist

When IP addresses are autoblocked, they appear in Special:Ipblocklist (but not in the admin's block log) with a special mask that prevents the IP from being seen. Autoblocks register on Special:Ipblocklist and in the banner available to the blocked user, with the name of the admin that set the original block. However, the admin is not notified that an autoblock has been placed. Diligent administrators who lift a block early, may wish to check the Ipblocklist in order to check for any autoblocks that need to be cleared.

Tips

• It is helpful for all involved, especially AOL users, who are often chronically autoblocked by collateral damage, to remain patient and remember that it is the software, not the administrator who is unfortunate enough to have his or her name appear on the block, who is responsible for the autoblock.
• Equally important is for admins to check Special:Ipblocklist regularly, and unblock all autoblocks from a particular user if more than two autoblocks are set in rapid succession.
• If more than two IPs are autoblocked within seconds/minutes of each other, it is a good indication that it is a dynamic IP pool and the blocks are collateral damage.
• Autoblocked users should email the admin, before posting angry messages to the mailing list, as 1) it isn't the admin's fault, and 2) it can quickly be taken care of without the need for hurt feelings.

Finally, users should know that autoblocked users are often still able to edit pages in the talk namespace, but not the main namespace. For instance, an autoblocked user is often able to edit Talk:Foo but not Foo itself. In this case, it is often possible for the user to leave a note for the admin directly on the admin's talk page. Make sure to note that it is an autoblock, as the admin may mistake your ability to post to his or her talk with being unblocked. It is imperative, whether you post to a talk page or contact an admin via email, that you include the IP address or username that is reported in the block text, as the admin has no way of determining which IP is autoblocking you.

See also

• Wikipedia:New admin school/Blocking