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Subject: Re: Loop detection (Was: HELO command)
From: Wietse Venema (wietseporcupine.org)
Date: Fri Aug 25 2000 - 13:27:57 CDT

What is the relationship of all this with HELO parameters and with
HELO replies, or has the thread shifted to something else while I
wasn't looking for a minute?

        Wietse

Rask Ingemann Lambertsen:
> Den 25-Aug-00 13:46:01 skrev Brad Knowles f_lgende om "Re: Loop detection (Was: HELO command)":
> >At 1:26 PM +0200 2000/8/25, Rask Ingemann Lambertsen wrote:
>
> >> This loop detection is broken! It incorrectly bounces mail in at least
> >> case like this one:
> >>
> >> $ORIGIN example.com
> >> postfixserver IN A 10.0.0.1
> >> realname IN MX 10 postfixserver
> >> alias IN CNAME realname
>
> > I'm pretty sure that this is one of the reasons why RFC 1123 says:
> [cut]
>
> > The loop detection code in postfix works the same way the code
> >does in sendmail, and both of them are correct.
>
> Actually, while this fails in Postfix, it does work in sendmail:
>
> [raskvissevasse rask]$ echo "Subject: test" | /usr/sbin/sendmail raskalias.lambertsen.cx
> [raskvissevasse rask]$ cat /var/spool/mail/rask
> >From rask Fri Aug 25 16:19:22 2000
> Return-Path: <rask>
> Received: (from rasklocalhost)
> by vissevasse.kampsax.dtu.dk (8.9.3/8.9.3) id QAA14629
> for raskalias.lambertsen.cx; Fri, 25 Aug 2000 16:19:21 +0200
> Date: Fri, 25 Aug 2000 16:19:21 +0200
> From: Rask Ingemann Lambertsen <raskvissevasse.kampsax.dtu.dk>
> Message-Id: <200008251419.QAA14629vissevasse.kampsax.dtu.dk>
> Subject: test
>
> [rootvissevasse /etc]# cat /etc/sendmail.cw
> # sendmail.cw - include all aliases for your machine here.
> realname.lambertsen.cx
> [rootvissevasse /etc]# dig MX alias.lambertsen.cx
>
> ; <<>> DiG 8.2 <<>> MX alias.lambertsen.cx
> ;; res options: init recurs defnam dnsrch
> ;; got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
> ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
> ;; QUERY SECTION:
> ;; alias.lambertsen.cx, type = MX, class = IN
>
> ;; ANSWER SECTION:
> alias.lambertsen.cx. 10M IN CNAME realname.lambertsen.cx.
> realname.lambertsen.cx. 10M IN MX 10 sendmailserver.lambertsen.cx.
>
> ;; ADDITIONAL SECTION:
> sendmailserver.lambertsen.cx. 10M IN A 192.38.213.235
>
> ;; Total query time: 3666 msec
> ;; FROM: vissevasse.kampsax.dtu.dk to SERVER: default -- 192.38.212.2
> ;; WHEN: Fri Aug 25 16:16:38 2000
> ;; MSG SIZE sent: 37 rcvd: 107
>
> /etc/sendmail.cf was generated from an unmodified /etc/sendmail.mc from
> RedHat Linux 6.2:
>
> [rootvissevasse /etc]# rpm -q -i -f /etc/sendmail.mc
> Name : sendmail Relocations: (not relocateable)
> Version : 8.9.3 Vendor: Red Hat, Inc.
> Release : 20 Build Date: Thu 17 Feb 2000 11:51:28 PM CET
> Install date: Sat 08 Apr 2000 07:59:43 AM CEST Build Host: porky.devel.redhat.com
> Group : System Environment/Daemons Source RPM: sendmail-8.9.3-20.src.rpm
> Size : 477388 License: BSD
> Packager : Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>
> Summary : A widely used Mail Transport Agent (MTA).
> Description :
> The Sendmail program is a very widely used Mail Transport Agent (MTA).
> MTAs send mail from one machine to another. Sendmail is not a client
> program, which you use to read your e-mail. Sendmail is a
> behind-the-scenes program which actually moves your e-mail over
> networks or the Internet to where you want it to go.
>
> If you ever need to reconfigure Sendmail, you'll also need to have the
> sendmail.cf package installed. If you need documentation on Sendmail,
> you can install the sendmail-doc package.
>
>
> It also looks as if qmail agrees with me and sendmail on this matter. I
> don't have a qmail box to play with to do the exact same experiment, but
> here is a setup which is close:
>
> carlsberg/home/rask">telnet://raskcarlsberg/home/rask> echo "Subject: test" | /usr/sbin/sendmail rask-lokalftp.kampsax.k-net.dk
> carlsberg/home/rask">telnet://raskcarlsberg/home/rask> cat .qmail-lokal
> carlsberg/home/rask">telnet://raskcarlsberg/home/rask> cat Mailbox
> >From raskkampsax.k-net.dk Fri Aug 25 14:34:19 2000
> Return-Path: <raskkampsax.k-net.dk>
> Delivered-To: rask-lokalcarlsberg.kampsax.k-net.dk
> Received: (qmail 29418 invoked from network); 25 Aug 2000 14:34:19 -0000
> Received: from carlsberg.kampsax.dtu.dk (qmailr192.38.212.2)
> by carlsberg.kampsax.dtu.dk with SMTP; 25 Aug 2000 14:34:19 -0000
> Received: (qmail 29414 invoked by uid 1146); 25 Aug 2000 14:34:18 -0000
> Date: 25 Aug 2000 14:34:18 -0000
> Message-ID: <20000825143418.29413.qmailcarlsberg.kampsax.dtu.dk>
> From: raskkampsax.k-net.dk
> Cc: recipient list not shown: ;
> Subject: test
>
> carlsberg/home/rask">telnet://raskcarlsberg/home/rask> cat /var/qmail/control/locals
> localhost
> carlsberg.kampsax.k-net.dk
> kampsax.k-net.dk
> carlsberg.kampsax.dtu.dk
> kampsax.dtu.dk
> carlsberg/home/rask">telnet://raskcarlsberg/home/rask> dig MX ftp.kampsax.k-net.dk
>
> ; <<>> DiG 8.2 <<>> MX ftp.kampsax.k-net.dk
> ;; res options: init recurs defnam dnsrch
> ;; got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
> ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0
> ;; QUERY SECTION:
> ;; ftp.kampsax.k-net.dk, type = MX, class = IN
>
> ;; ANSWER SECTION:
> ftp.kampsax.k-net.dk. 29m59s IN CNAME carlsberg.kampsax.k-net.dk.
>
> ;; AUTHORITY SECTION:
> kampsax.k-net.dk. 29m59s IN SOA carlsberg.kampsax.dtu.dk. netgrp.kampsax.dtu.dk. (
> 1000825030 ; serial
> 1H ; refresh
> 15M ; retry
> 4w2d ; expiry
> 29m59s ) ; minimum
>
>
> ;; Total query time: 2 msec
> ;; FROM: carlsberg.kampsax.dtu.dk to SERVER: default -- 192.38.212.2
> ;; WHEN: Fri Aug 25 16:35:03 2000
> ;; MSG SIZE sent: 38 rcvd: 143
>
> carlsberg.kampsax.k-net.dk runs qmail 1.01.
>
> That said, don't fix the loop detection just because Sendmail and qmail
> work differently, fix it because it is broken.
>
> Regards,
>
> /________________________________T_______________________________________\
> | Rask Ingemann Lambertsen | E-mail: mailto:raskkampsax.k-net.dk |
> | A4000, 896 kkeys/s (RC5-64) | "ThrustMe" on XPilot, ARCnet and IRC |
> | Paperweights -- The only way to keep bills down. |
>
>
>
>
>