Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!tut.cis.ohio-state.edu!ucbvax!MCSUN.EU.NET!piet
From: piet@MCSUN.EU.NET (Piet Beertema)
Newsgroups: comp.protocols.tcp-ip.domains
Subject: Re: Bad MXer relay.eu.net for .ch domains
Message-ID: <9005311630.AA15557@mcsun.EU.net>
Date: 31 May 90 16:30:27 GMT
References: <9005311505.AA09588@Gipsi.Gipsi.Fr>
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: inet
Organization: The Internet
Lines: 24


	I think what should have happened was that "relay.eu.net" should
	have been a CNAME for mcsun.eu.net...
No, that was never intended and it would be wrong too.
The name relay.EU.net is only used in conjunction with
the gateway function(s) of mcsun.EU.net: in that case
mcsun will generate header From: lines of the form
  From: host!user@relay.EU.net
or
  From: user%node.bitnet@relay.EU.net

If relay.EU.net were a CNAME for mcsun.EU.net, these
forms would be incorrect (can't remember right now in
which rfc to find it) and sendmail 5.61 is known to
generate a "Cannot prescan canonical hostname" error
if you use it that way.

Since a CNAME RR would be wrong and the real hostname
is mcsun.EU.net, there is no A RR, but an MX RR for
relay.EU.net pointing to mcsun.EU.net to ensure proper
routing of replies.


	Piet