Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!ns-mx!handlebar.weeg.uiowa.edu!jnford
From: jnford@handlebar.weeg.uiowa.edu (Jay Ford)
Newsgroups: comp.protocols.tcp-ip.domains
Subject: Re: Domain level mail addressing
Message-ID: <3669@ns-mx.uiowa.edu>
Date: 19 Dec 90 22:10:56 GMT
References: <1990Dec17.081050@acad3a.alaska.edu>
Sender: news@ns-mx.uiowa.edu
Reply-To: jnford@handlebar.weeg.uiowa.edu (Jay Ford)
Organization: Weeg Computing Center, University of Iowa, Iowa City, IA, USA
Lines: 45


In article <1990Dec17.081050@acad3a.alaska.edu>, sxjlh@acad3a.alaska.edu
(Jeff Harrison) writes:
|> I want to set up our domain server to accept mail queries for our top level
|> domain ALASKA.EDU 
|> and translate them to our mailer host ACAD3.ALASKA.EDU.  I've seen
other sites
|> with mail
|> addresses listed as userid@domain.  To be specific, I'd like to have
my address
|> be listed as
|> sxjlh@alaska.edu.  Then our domain server will resolve alaska.edu to be
|> acad3.alaska.edu.  I've been unable to code the SOA to deal with it.  I can
|> enter CNAME records for acad3 to be alaska.edu., but then mail attempts to
|> deliver to sxjlh@alaska.edu and the host doesn't exist.  I've been
told by some
|> that this is a mail specific issue but it seems to me bind should be able to
|> handle this.  We are running our bind server on a VAX/VMS system
using WIN/TCP
|> 5.1.

You can't use CNAMEs in the situation you describe, because both names other
data (at least SOA & NS for alaska.edu, and A for acad3.alaska.edu).

There are several things you need to do:
    o	add an MX record for alaska.edu pointing to acad3.alaska.edu
	(with whatever preference you want)
    o	add an A record for alaska.edu with the address of acad3.alaska.edu
	(this will allow dumb non-MX mailers to mail to user@alaska.edu)
    o	convince the mailer on acad3.alaska.edu to accept mail addressed to
	user@alaska.edu (in addition to user@acad3.alaska.edu);  this probably
	amounts to telling the mailer on acad3.alaska.edu that it is also known
	by the name alaska.edu, but I don't know what it takes in your
	environment (I don't do VMS :^)

The mail will come in addressed to user@alaska.edu.  The mail routing and
address DNS data does not affect the recipient mail address.  It just dictates
which system gets the mail.  This is why you need to do the third thing.

For an example, take a look at the A and MX data for uiowa.edu to see how it is
pointed at ns-mx.uiowa.edu for mail.


Jay Ford,  Weeg Computing Center,  University of Iowa,  Iowa City,  IA  52242
jnford@handlebar.weeg.uiowa.edu  or  jnfordpb@uiamvs.bitnet,  319-335-5555