http://support.microsoft.com/default.aspx?scid=kb;[LN];884020
"On a computer that is running Microsoft Windows XP with Service Pack 2
(SP2), programs that connect to IP addresses that are in the loopback
address range may not work as you expect."
Amazing, hotfixing an issue in SP2, which is just released
to WU.
Wish I could work that fast.
"A supported hotfix is now available from Microsoft, but it is only intended
to correct the problem that is described in this article. Only apply it to
systems that are experiencing this specific problem. This hotfix may receive
additional testing. Therefore, if you are not severely affected by this
problem, we recommend that you wait for the next Windows XP service pack
that contains this hotfix."
That must be SP3