From: gaissmai@xwini.rz.uni-ulm.de (Karl Gaissmaier)
Subject: problems with ultrix sendmail: i refuse to talk to myself
Keywords: sendamil, ultrix, MX
Organization: Universitaet Ulm
Date: Mon, 14 Dec 1992 08:43:52 GMT

In article <1992Dec8.151636.12830@htlulx.htl-bw.ch>, 
kupfer@htlulx.htl-bw.ch (Kupferschmid Christian) writes:

|> I have a DECstation 5000/200 with ULTRIX 4.2 0 whitch is out domain name
|> server and receipient of the mx mails. Now I have the problem that a
|> mail sent to the domain or the machine specificaly will be returned to
|> the sender with following message:
|> 
|>    ----- Transcript of session follows -----
|> <<< RCPT To:<kupfer@htlulx.htl-bw.ch>
|> <<< DATA
|> >>> HELO htlulx.htl-bw.ch
|> <<< 553 htlulx.htl-bw.ch I refuse to talk to myself
|> 554 <kupfer@htlulx.htl-bw.ch>... Service unavailable: Bad file number
|> 
|> Where is the problem or what is the bug?


i have a similar configuration and the same problem:

MikroVax-3100
ULTRIX V4.2 (Rev. 85)
Sendmail-5.57

This machine (netway.rz.uni-ulm.de) is our domain name server and MX-Server 
for various other machines. netway is also our backup MailExchanger for 
mathematik.uni-ulm.de, see below:

  xwini$ nslookup
  Default Server:  netway.rz.uni-ulm.de
  Address:  134.60.1.1

  > set type=MX
  > mathematik.uni-ulm.de.
  Server:  netway.rz.uni-ulm.de
  Address:  134.60.1.1

  mathematik.uni-ulm.de   preference = 0, mail exchanger = laborix.mathematik.uni-ulm.de
  mathematik.uni-ulm.de   preference = 5, mail exchanger = titania.mathematik.uni-ulm.de
  mathematik.uni-ulm.de   preference = 100, mail exchanger = netway.rz.uni-ulm.de
  mathematik.uni-ulm.de   preference = 200, mail exchanger = noc.belwue.de
  mathematik.uni-ulm.de   preference = 210, mail exchanger = iraun1.ira.uka.de
  laborix.mathematik.uni-ulm.de   inet address = 134.60.66.1
  titania.mathematik.uni-ulm.de   inet address = 134.60.66.21
  netway.rz.uni-ulm.de    inet address = 134.60.1.1
  noc.belwue.de   inet address = 129.143.2.1
  iraun1.ira.uka.de       inet address = 129.13.10.90
  >

in the case, that both MX-Servers laborix.mathematik.uni-ulm.de and
titania.mathematik.uni-ulm.de are down at the same time, all mails
for mathematik.uni-ulm.de are sent to netway.rz.uni-ulm.de.

The netway now doesn't queue the mails until the more precedenced
MX_Servers laborix or titania are online, netway tries to connect
with itself and in order to prevent loops, netway can only say:
	i refuse to talk to myself

this message is okay, but to try to connect with itself is forbidden
in RFC-974:

======================== citation of rfc-974============================

General Routing Guidelines

   Before delving into a detailed discussion of how mailers are expected
   to do mail routing, it would seem to make sense to give a brief
   overview of how this memo is approaching the problems that routing
   poses.

   The first major principle is derived from the definition of the
   preference field in MX records, and is intended to prevent mail
   looping.  If the mailer is on a host which is listed as an MX for the
   destination host, the mailer may only deliver to an MX which has a
   lower preference count than its own host.

=========================================================================

but thats not my only problem with sendmail on ultrix.
We have the following wildcard-MX-RR's:

  xwini$ nslookup
  Default Server:  netway.rz.uni-ulm.de
  Address:  134.60.1.1

  > set type=MX
  > *.rz.uni-ulm.de.
  Server:  netway.rz.uni-ulm.de
  Address:  134.60.1.1

  *.rz.uni-ulm.de preference = 0, mail exchanger = netway.rz.uni-ulm.de
  netway.rz.uni-ulm.de    inet address = 134.60.1.1
  >

but when i mail to an unexisting host there is the same error,
because the netway tries again to connect with itself:

	Return-Path: MAILER-DAEMON@netway.rz.uni-ulm.de
	Received: by netway.rz.uni-ulm.de (5.57/UniUlm-1.0dm)
		id AA23265; Fri, 11 Dec 92 09:50:15 +0100
	Date: Fri, 11 Dec 92 09:50:15 +0100
	From: MAILER-DAEMON@netway.rz.uni-ulm.de (Mail Delivery Subsystem)
	Subject: Returned mail: Service unavailable
	Message-Id: <9212110850.AA23265@netway.rz.uni-ulm.de>
	To: postmaster@netway.rz.uni-ulm.de
	To: <gaissmai@xwini.rz.uni-ulm.de>

	   ----- Transcript of session follows -----
	<<< RCPT To:<foo@bar.rz.uni-ulm.de>
	<<< DATA
	>>> HELO netway.rz.uni-ulm.de
	<<< 553 netway.rz.uni-ulm.de I refuse to talk to myself
	554 <foo@bar.rz.uni-ulm.de>... Service unavailable: Bad file number

	   ----- Unsent message follows -----
	Received: by netway.rz.uni-ulm.de (5.57/UniUlm-1.0dm)
		id AA23263; Fri, 11 Dec 92 09:50:15 +0100
	Received: by xwini.rz.uni-ulm.de (5.57/Ultrix3.0-C)
		id AA11778; Fri, 11 Dec 92 09:49:59 +0100
	Date: Fri, 11 Dec 92 09:49:59 +0100
	From: gaissmai@xwini.rz.uni-ulm.de (Karl Gaissmaier)
	Message-Id: <9212110849.AA11778@xwini.rz.uni-ulm.de>
	Subject: MX-Test
	Apparently-To: foo@bar.rz.uni-ulm.de

and the sender gets the error-message:

	<<< 553 netway.rz.uni-ulm.de I refuse to talk to myself
	554 <foo@bar.rz.uni-ulm.de>... Service unavailable: Bad file number

and not "unknown host" and that is very painful.

a related problem exist with CNAME entries and $[foo.bar$] rewrite patterns
but i believe i don't have to describe this behavior, because it's clear
that "something" is wrong with DEC's sendmail.

Don't bother me with Ultrix-4.3, that's the same, i tried it on the fly.


thanks for any suggestions or solutions ?

=========================================================================
Karl Gaissmaier                      gaissmai@rz.uni-ulm.de
Rechenzentrum Uni Ulm               
Albert Einstein Allee 11             Telefon: (Germany) 0731/5022499
W-7900 Ulm / Germany                 Telefax: (Germany) 0731/5022471
=========================================================================
Newsgroups: comp.mail.sendmail