Microsoft has issued a formal fix for a problem in Windows XP Service Pack 2 that appeared almost immediately after the updates release.
The problem, which affected many VPN users, causes errors when programs attempt to connect to loop-back addresses other than 127.0.0.1. Service Pack 2 blocks all such addresses; users receive an error message saying that they cannot establish a connection.
Microsoft had issued a hotfix for the problem last month, but the new update is more thoroughly tested and available to all without having to go through Microsoft Product Support Services.
The fix was not issued in the normal fix cycle, but that cycle applies mainly to security issues. This is the first formal fix issued for Windows XP SP2, which had no reported errors in the most recent patch day. The drag-and-drop flaw in SP2s Internet Explorer remains unaddressed.