Errors-to: owner-drums@CS.UTK.EDU
Message-Id: <199509220740.DAA17233@wilma.cs.utk.edu>
To: drums@CS.UTK.EDU
Subject: support for Postmaster address
cc: moore@CS.UTK.EDU
From: Keith Moore <moore@CS.UTK.EDU>
Date: Fri, 22 Sep 1995 03:40:25 -0400
Sender: moore@CS.UTK.EDU

RFC 821 requires that all hosts support mail to "Postmaster".

But it's not clear in the world of MX records whether the
Postmaster address must be supported for every domain name
that can possibly receive mail, or for every parent domain
of a domain that can possibly receive mail.

I'm tempted to suggest that the Postmaster address must be
supported for 

+ any domain that appears on the right-hand side of an @ in a 
  sender address (either header or envelope), or

+ any domain which is listed as a mail exchanger for some other 
  domain, or

+ any domain which appears in a Received header.

Also, when trying to track down a mail problem at a remote
host, I almost invariably find that the Postmaster address
at that host does not work -- neither postmaster@remote-domain
nor postmaster@mail-exchanger is recognized, and I'm reduced
to looking at the DNS SOA record or the InterNIC's whois database
to try and identify a contact at the broken site. 

So I am wondering whether we can require an MTA to test
on startup whether it knows how to route mail to Postmaster, 
and if not, to refuse to send or accept mail until this is fixed.

(In particular, it should know how to route mail to 
postmaster@local.domain.name and postmaster@[my.ip.address].)

This might sound like a radical step, but it has the very
desirable property that the problem is noticed by those
who are in the best position to fix it.

Keith