How to allow really anonymous edits in mediawiki?
Fragment of a discussion from Project:Support desk
I agree that I know of no such configuration setting or extension which makes the IP's of anonymous users hidden, but my suggestion is a part of what was asked. Also, I suggest setting $wgShowIPinHeader to false to prevent the anonymous user from seeing his/her IP (and it will also reduce the required server resources, because each different IP has to be loaded separately).
