If you administer a MediaWiki Wiki, youve probably come across wiki spam. There is a quite simple way of fixing this. Just edit the file
LocalSettings.php in the root directory and add the following line at the bottom (or anywhere else):
$wgGroupPermissions['*']['edit'] = false;
This will remove the edit-permissions from users who have not yet logged in. If a guest tries to edit, they will be prompted to log in. Since you would no longer be able to edit using only your IP address as a signature, adding the following line might be desired too:
$wgShowIPinHeader = false;
Doing so removes the IP address from the header for non-logged-in users (logged-in users wouldnt see it anyway). Happy wikiing.