A.7.17 Since I upgraded Windows XP to Service Pack 2, I can't use addresses like 127.0.0.2.

Some people who ask PuTTY to listen on localhost addresses other than 127.0.0.1 to forward services such as SMB and Windows Terminal Services have found that doing so no longer works since they upgraded to WinXP SP2.

This is apparently an issue with SP2 that is acknowledged by Microsoft in MS Knowledge Base article 884020. The article links to a fix you can download.

(However, we've been told that SP2 also fixes the bug that means you need to use non-127.0.0.1 addresses to forward Terminal Services in the first place.)