Re: [exim] Unusual Behavior

Harold Huggins wrote:
> SMTP Mail Relay between the local host and remote computer exhibits the
> following behavior:
>
> ~$ telnet dslxxxxxxxx.com 25
> Trying 72.167.97.127...
> Connected to dslxxxxxxxx.com.
> Escape character is '^]'.
> 220-ms.dslxxxxxxxx.com ESMTP Exim 4.69 #1 Wed, 21 Oct 2009 13:34:34 -0700
> 220-We do not authorize the use of this system to transport unsolicited,
> 220 and/or bulk e-mail.
> helo mail.dyndns.com
> 250 ms.dslxxxxxxxx.com Hello xen.thisisnotatrueending.com [216.146.46.13]
> mail from:noone@???
> 250 OK
> rcpt to:support@???
> 421 Unexpected failure, please try later
> rcpt to:admin@???
> 421 Unexpected failure, please try later
> rcpt to:doesnotexist@???
> 421 Unexpected failure, please try later
> rcpt to:fdfd
> 421 Unexpected failure, please try later
> rcpt to:421 Unexpected failure, please try later
> exit 421 Unexpected failure, please try later
> quit 221 ms.dslxxxxxxxx.com closing connection
> Connection closed by foreign host.
>
> For each of the above RCPT TO lines, your server should return a
> 500-level permanent failure error.

Not unless it *IS* a permanent failure.

This says otherwise, and Exim is usually 'very' correct on that score.

e.g - a custom error message might overide default text, and getting the custom
text 'right' is up to the admin. But the number-codes are what they are supposed
to be.

Depending on how strict a test is set up, and how driven, behaviour of this sort
can be the result of inability to access lookup tables or connect to a local DB
or remote BL. If/as/when the resources are once again available, a retry gets
handled accordingly.


> For example:
>
> rcpt to:support@???
> 421 Unexpected failure, please try later
>
> should become:
>
> rcpt to:support@???
> 550 Relay denied
>

Only if it is clear that 'denied' is a certainty.
It may not be getting far enough to ascertain that.

> Of course, your server should accept mail for itself:
>
> rcpt to:admin@???
> 250 OK
>

Not necessarily so it the connection arrives from a forbidden IP (RBL, LBL, or
just plain lacking a valid PTR/MX match. Depends on what the mailadmin
considered important.

My servers will not even complete the telnet response in such cases, so you see
only a blank screen.


> Similarly, and likely related to this behavior, the local server
> transmitting all of the mail it received (potentially forwarding) to
> itself via Outbound, using the sender's address as the From: address:
>

'Might be' a misconfigration. Not able to tell what it was *intended* to do.

You need to contact the mailadmin of the Exim server and ask that (s)he check
the logs, the ~/configure file, DNS availability, perhaps run a few debug traces.

HTH,

Bill Hacker

> 2009-10-21 18:00:38 1N0fUE-000HqZ-NG <= automailer@???
> H=ip-72-167-97-127.ip.secureserver.net (ms.dslxxxxxxxx.com)
> [72.167.97.127] P=esmtpsa X=TLSv1:AES256-SHA:256 A=login:uisiscom S=2688
> id=20091020060530.E40F036177B@???
> 2009-10-21 18:00:39 1N0fUE-000HqZ-NG => admin@???
> R=dnslookup T=remote_smtp H=mx1.mailhop.org [216.146.33.1]
> 2009-10-21 18:00:39 1N0fUE-000HqZ-NG Completed
>
> 2009-10-21 18:00:59 1N0fUZ-000Hvz-6h <= notifier07@???
> H=ip-72-167-97-127.ip.secureserver.net (ms.dslxxxxxxxx.com)
> [72.167.97.127] P=esmtpsa X=TLSv1:AES256-SHA:256 A=login:uisiscom S=4185
> id=5438227.418371256102709656.JavaMail.root@???
> 2009-10-21 18:00:59 1N0fUZ-000Hvz-6h no immediate delivery: more than 15
> messages received in one connection
>
>
> 2009-10-21 18:07:23 1N0fal-000KwZ-IM <= bounces@???
> H=ip-72-167-97-127.ip.secureserver.net (ms.dslxxxxxxxx.com)
> [72.167.97.127] P=esmtpsa X=TLSv1:AES256-SHA:256 A=login:uisiscom S=6456
> id=1195177925.98772@???
> 2009-10-21 18:07:24 1N0fal-000KwZ-IM => beta@??? R=dnslookup
> T=remote_smtp H=mx1.mailhop.org [216.146.33.3]
> 2009-10-21 18:07:24 1N0fal-000KwZ-IM Completed
>