Mailing List Message #11705
From: Warren Michelsen <>
Subject: Addressing to an IP Address
Date: Sun, 8 Sep 2002 11:28:23 -0700
To: SIMS Discussions <>
The last I heard, addressing email to an IP address in the form : support@[] was perfectly legal. The folks at have some really screwed up DNS and went and changed class Cs. Now their server is (mostly) unreachable because most lookups result in non-authoritative data that is out of date.

Anyway, instead of, I sent email to support@[] which should have gone through. Now, I know these guys use Windows NT. Is this problem" 550 unknown user" due to some brain-damaged MS email server they use?

Failed to deliver your message to support@[]:
SMTP: Address rejected by host
Host '[]' says:
550 unknown user <support@[]>

Reporting-MTA: dns;

Final-Recipient: rfc822; support@[]
Action: failed
Status: 5.0.0
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