[comp.protocols.tcp-ip.domains] Domain level mail addressing

sxjlh@acad3a.alaska.edu (Jeff Harrison) (12/18/90)

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.

Jeff Harrison
Systems Programmer
University of Alaska Computer Network
sxjlh@acad3.alaska.edu

jnford@handlebar.weeg.uiowa.edu (Jay Ford) (12/20/90)

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

peiffer@cs.umn.edu (Tim Peiffer "The Net Guy") (12/20/90)

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
[..]
>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

This is both a BIND and a Sendmail issue.  Once you translate the name
to the IP address of acad3, the mailer should be reconfigured so that 
it knows that acad3 is LOCAL.  If you do not fix this problem, sendmail
will sense a loop returning errors of "I refuse to talk to myself".  Below
are excerpts of our sendmail.cf rewrite rules and named zone files required
to do this at our site.

Tim Peiffer
----------------
Tim Peiffer				peiffer@cs.umn.edu 	or
Computer Science Dept			..!rutgers!umn-cs!peiffer
University of Minnesota
MPLS MN 55455


--------/usr/lib/sendmail.cf -----------
#################################
#   special local conversions   #
#################################

S6
R$*<@umn-cs.cs.umn.edu>$*	$1<@cs.umn.edu>$2
R$*<@$=w>$*		$:$1<@LOCAL>$3

---------/etc/named/hosts  and hosts.rev
$ORIGIN cs.umn.edu.
@		IN	SOA	cs.umn.edu. peiffer.cs.umn.edu. (
				;My SOA goes here.
                                )
		IN	NS	cs.umn.edu.
				;The rest of my NS records here.
		IN	MX	10 cs.umn.edu.
		IN	MX	11 umn-cs.cs.umn.edu.
		IN	A	128.101.224.1
umn-cs		IN	A	128.101.224.1

$ORIGIN	224.101.128.IN-ADDR.ARPA.

		; My SOA's and NS here again

1		IN	PTR	cs.umn.edu.



-- 
-----------
Tim Peiffer				peiffer@cs.umn.edu 	or
Computer Science Dept			..!rutgers!umn-cs!peiffer
University of Minnesota

gary@proa.sv.dg.com (Gary Bridgewater) (12/21/90)

In article <1990Dec20.153846.3716@cs.umn.edu> peiffer@cs.umn.edu (Tim Peiffer "The Net Guy") writes:
>R$*<@$=w>$*		$:$1<@LOCAL>$3

Well, sure. But what if class w doesn't contain the unqualified name of the host?
I just brought up the UIUC version of sendmail 5.65 and it only defines the FQDN.
Also, the Suns around here running the MX sendmail do the same thing. This was
very irritating and took a major kludge to work around.
-- 
Gary Bridgewater, Data General Corporation, Sunnyvale California
gary@sv.dg.com or {amdahl,aeras,amdcad}!dgcad!gary
C++ - it's the right thing to do.

paul@uxc.cso.uiuc.edu (Paul Pomes - UofIllinois CSO) (12/22/90)

gary@proa.sv.dg.com (Gary Bridgewater) writes:

>In article <1990Dec20.153846.3716@cs.umn.edu> peiffer@cs.umn.edu (Tim Peiffer "The Net Guy") writes:
>>R$*<@$=w>$*		$:$1<@LOCAL>$3
>
>Well, sure. But what if class w doesn't contain the unqualified name of the host?
>I just brought up the UIUC version of sendmail 5.65 and it only defines the FQDN.
>Also, the Suns around here running the MX sendmail do the same thing. This was
>very irritating and took a major kludge to work around.

In the UIUC/NIU IDA sendmail, class w does contain the UUCP version of the
hostname.  If a bare host name cannot be qualified into a domain, it's
punted to the .UUCP domain.  Names for the localhost will have been qualified
into the local domain before the ruleset above is used anyway.

What in particular is irritating about using just the FQDN?

/pbp
--
         Paul Pomes

UUCP: {att,iuvax,uunet}!uiucuxc!paul   Internet, BITNET: paul@uxc.cso.uiuc.edu
US Mail:  UofIllinois, CSO, 1304 W Springfield Ave, Urbana, IL  61801-2910

gary@proa.sv.dg.com (Gary Bridgewater) (12/22/90)

In article <1990Dec21.194323.7785@ux1.cso.uiuc.edu> paul@uxc.cso.uiuc.edu (Paul Pomes - UofIllinois CSO) writes:
>gary@proa.sv.dg.com (Gary Bridgewater) writes:
>
>In the UIUC/NIU IDA sendmail, class w does contain the UUCP version of the
>hostname.  If a bare host name cannot be qualified into a domain, it's
>punted to the .UUCP domain.  Names for the localhost will have been qualified
>into the local domain before the ruleset above is used anyway.

Yes.

>What in particular is irritating about using just the FQDN?

After a series of mail exchanges with Neil W. Rickert of Northern Illinois
University, CS department,  I saw the error of my ways.  I had read the MX
documentation some months ago but not brought it up until now.  I completely
forgot $[ $] (which will qualify a bare host - or even a partially
qualified one).  Given that, there is no problem.  Just a bad case of linear
thinking that got out of control.
-- 
Gary Bridgewater, Data General Corporation, Sunnyvale California
gary@sv.dg.com or {amdahl,aeras,amdcad}!dgcad!gary
C++ - it's the right thing to do.