[Mailman-Users] Subscription requests vanish

[Marc Lanctot]

Hi guys,

I'm a system administrator at McGill University. We're in the process 
migrating an old FreeBSD lab to Linux. One thing I'm in charge of is 
updating the mailing list. Here's my setup:

The webserver for the CND department is located as www.cnd.mcgill.ca, 
which points to cube.cnd.mcgill.ca (132.216.11.165). We're using 
sendmail for email, hosted on mailhost.cnd.mcgill.ca which also points 
to cube.cnd.mcgill.ca.

I'm using Fedora Core 2. GNU Mailman was setup via apt. I followed all 
the instructions in INSTALL.REDHAT and README in /usr/share/doc/mailman. 
I setup a default mailing list called "mailman" for testing. I set 
DEFAULT_URL_HOST to 'www.cnd.mcgill.ca', and DEFAULT_EMAIL_HOST to 
'cnd.mcgill.ca' as instructed via comments in the 
/var/mailman/Mailman/mm_cfg.py file.

Now, I send an email from my address (<< firstname . lastname >> @ 
mail.mcgill.ca) to mailman-subscribe at cnd.mcgill.ca. This uses the 
McGill-wide SMTP host mailhost.mcgill.ca.

tcpdump (ran on cube, see below) shows me that there is indeed SMTP 
communication between mailhost.mcgill.ca(seen as 'deluge' below) and 
cube.cnd.mcgill.ca. The mailman /var/log/mailman/subscribe file shows 
lines like so:

Jul 30 18:55:28 2004 (17315) mailman: pending Marc Lanctot 
<marc.lanctot at mail.mcgill.ca>  marc.lanctot at mail.mcgill.ca

and /var/log/mailman/smtp:

Jul 30 19:03:07 2004 (17403) 
<mailman.0.1091226527.17107.mailman at cnd.mcgill.ca> smtp for 1 recips, 
completed in 0.009 seconds

but smtp-failure shows lines like so:

Jul 30 19:03:07 2004 (17403) Low level smtp error: (111, 'Connection 
refused'), msgid: <mailman.0.1091227549.17254.mailman at cnd.mcgill.ca>
Jul 30 19:03:07 2004 (17403) delivery to marc.lanctot at mail.mcgill.ca 
failed with code -1: (111, 'Connection refused')

So it seems that some machine is refusing SMTP connections somewhere, 
but it doesn't say which machine!! No smtp packets even showed up from 
cube in the TCP dump (maybe this is only sucessfully received packets?) 
other than to mailhost.mcgill.ca. I expected to see some smtp 
communication on the local machine to send out bouncebacks or something.

What I do know id that mailman or sendmail does an MX lookup on my 
email's domain (mail.mcgill.ca) at some point because it shows up in 
tcpdump. But other than that, it's stuck there contacting some smtp host 
and not getting through it seems...

Sorry for the long email! Any help is gladly appreciated.

Marc



% tcpdump | grep smtp
18:42:11.846880 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
S 3817025147:3817025147(0) win 24820
<nop,nop,sackOK,mss 1460>
18:42:11.846967 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
S 2808362076:2808362076(0) ack 381702
5148 win 5840 <mss 1460,nop,nop,sackOK>
18:42:11.847246 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
. ack 1 win 24820
18:42:11.856482 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
P 1:89(88) ack 1 win 5840
18:42:11.856816 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
. ack 89 win 24820
18:42:11.857171 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
P 1:27(26) ack 89 win 24820
18:42:11.857196 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
. ack 27 win 5840
18:42:11.858926 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
P 89:315(226) ack 27 win 5840
18:42:11.859378 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
P 27:77(50) ack 315 win 24820
18:42:11.865593 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
P 315:369(54) ack 77 win 5840
18:42:11.865948 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
P 77:126(49) ack 369 win 24820
18:42:11.870542 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
P 369:480(111) ack 126 win 5840
18:42:11.872207 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
P 126:975(849) ack 480 win 24820
18:42:11.911346 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
. ack 975 win 6792
18:42:11.911692 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
P 975:978(3) ack 480 win 24820
18:42:11.911748 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
. ack 978 win 6792
18:42:11.917176 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
P 480:536(56) ack 978 win 6792
18:42:11.942546 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
P 978:984(6) ack 536 win 24820
18:42:11.942734 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
P 536:585(49) ack 984 win 6792
18:42:11.942845 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
F 585:585(0) ack 984 win 6792
18:42:11.943052 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
F 984:984(0) ack 585 win 24820
18:42:11.943077 IP cube.cnd.mcgill.ca.smtp > deluge.CC.McGill.CA.59640: 
. ack 985 win 6792
18:42:11.943147 IP deluge.CC.McGill.CA.59640 > cube.cnd.mcgill.ca.smtp: 
. ack 586 win 24820