Re: Unable to receive e-mail from particular domain

"Ronald Nissley" <dont@xxxxxxx> writes:

I'll be the first to admit comp.mail.sendmail is not the right place for
this post, but I'm not sure where to go. I may be in over my head, but
I'm not ready to shell out $100/hr (think small-to-med non-profit). I
believe the problem is a network configuration (DNS, etc) issue as
opposed to a mail server issue but would appreciate any input from you
e-mail veterans out there.

First, a little background:

We've been running an Exchange 2003 (SP2) server behind NAT for some
time. In December of '05, we acquired a netblock to support an
additional server (Fedora Core 4) running Sendmail 8.13.4. It hosts
Mailman, Request Tracker, and a few other things. We're _considering_
using the Sendmail system as a mail gateway and not allowing external
mail to be sent directly to/from the Exchange server, but I digress. So,
one public IP address is NATted to the Exchange box, and another is
NATted to the Sendmail box. In our public DNS records, an MX record
(priority 10), exch.mydomain.tld in the mydomain.tld namespace, points
to the public IP address for Exchange and a 2nd MX record (priority 10),
sendmail.mydomain.tld in a subdomain namespace sendmail.mydomain.tld,
points to the public IP address for Sendmail.

Since acquiring the netblock, we are unable to receive e-mail from one
particular contact, somebody@xxxxxxxxxxx Onetel is the only known
instance, and based on mail server logs, the problem appears to coincide
exactly with the date we acquired the netblock. We consistently exchange
e-mail with numerous other domains.

From the Exchange logs, it's obvious a Onetel server connects to our
Exchange box for e-mail sent from this contact to user@xxxxxxxxxxxxx
From Sendmail logs, it's obvious a Onetel server connects to our
Sendmail box for e-mail sent from this contact to
user@xxxxxxxxxxxxxxxxxxxxxx

For e-mail sent to Exchange users, the Onetel user eventually receives
an NDR like:

Hi. This is the qmail-send program at onetel.com.
I'm afraid I wasn't able to deliver your message to the following
addresses.
This is a permanent error; I've given up. Sorry it didn't work out.
<user@xxxxxxxxxxxx>:
Connected to XXX.XXX.XXX.XXX but connection died. (#4.4.2) I'm not going
to try again; this message has been in the queue too long.

After acquiring the netblock, entries in the Exchange logs for Onetel
servers are like the following:

06:51:54 212.67.120.103 QUIT - 240

And with some additional logging turned on (EXCH being the netbios name
of our mail server):

212.67.120.103 - EXCH 240 59984 -
212.67.120.103 - EXCH 240 59984 -
212.67.120.103 - EXCH 240 60000 -
212.67.120.103 - EXCH 240 59984 -

I _think_ the 59984 and 60000 are Exchange/SMTP substatus codes. I'm not
sure and wasn't able to locate a reference for such codes.

In the Sendmail logs (after bumping the logging level to 14):

Feb 23 15:39:54 localhost sendmail[29396]: NOQUEUE: connect from
perdition3.onetel.net.uk [212.67.120.103]
Feb 23 15:39:54 localhost sendmail[29396]: AUTH: available mech=CRAM-MD5
DIGEST-MD5, allowed mech=LOGIN PLAIN
Feb 23 15:39:54 localhost sendmail[29396]: k1NKdsKr029396: Milter: no
active filter
Feb 23 15:40:53 localhost sendmail[29396]: k1NKdsKr029396:
perdition3.onetel.net.uk [212.67.120.103] did not issue
MAIL/EXPN/VRFY/ETRN during connection to MTA

Insight/input is welcomed and will be appreciated. You can send e-mail
to rnissley.gmail.com. Replace the first period with @.

[ about exchange ask in microsoft.* groups ]

1) Can you ask the postmaster of onetel to telnet smtp port of you
sendmail and measure exactly how long it takes to get the greeting
message? [be ready for 10m+ delay (reported in extreme cases)]

2) What OS/distribution do you use at sendmail host?
It may be handy for recomending advanced "non sendmail" debugging and
guessing some *rare* OS/distribution specific problems.

--
[pl2en Andrew] Andrzej Adam Filip : anfi@xxxxxxxxxxxx : anfi@xxxxxxxx
http://anfi.homeunix.net/
.

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