Re: postfix not sending mail in the queue

From	Jim Diamond <zsd@jdvb.ca>
Newsgroups	alt.os.linux.slackware
Subject	Re: postfix not sending mail in the queue
Date	2025-12-27 13:04 -0400
Organization	A noiseless patient Spider
Message-ID	<slrn10l04dd.1sc.zsd@x360.localdomain> (permalink)
References	(1 earlier) <69426af3$1@news.ausics.net> <slrn10kjebg.9ct.zsd@x360.localdomain> <6949c24d$1@news.ausics.net> <slrn10kp0c3.3tn.zsd@x360.localdomain> <slrn10krilc.iag.syl@elvira.therockgarden.ca>

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On 2025-12-25 at 19:37 AST, Sylvain Robitaille <syl@therockgarden.ca> wrote:
> On 2025-12-25, Jim Diamond wrote:
>
>> Here is the message in maillog when it tried to send an email while the
>> network was down:
>>
>> ------------------
>> ...
>> Dec 16 15:05:58 x360 postfix/smtp[2479]: AA6B21E0B4C: to=<ntg-context@ntg.nl>, relay=none, delay=0.05, delays=0.03/0.01/0/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=MY_SMTP_SERVER type=A: Host not found, try again)
>> ------------------
>
> Ok, that's not surprising ...
>
>> Once the network was back, I tried running the queue:
>>
>> ------------------
>> ...
>> Dec 16 15:06:17 x360 postfix/smtp[2479]: AA6B21E0B4C: to=<ntg-context@ntg.nl>, relay=none, delay=19, delays=19/0/0/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=MY_SMTP_SERVER type=A: Host not found, try again)
>> ------------------
>
> But this is ...

Yeah, surprises me too.

> Here's a thought ... It won't help solve the problem but it might
> help identify the cause ...
>
> Perhaps just before and just after running "sendmail -v -q" try running
> "getent hosts MY_SMTP_SERVER" (with the correct hostname, of course)
> and confirm that the system is generally able to resolve the hostname?

> Based on the timestamps from your log extracts above, I'm guessing
> (and yes, only guessing) that the attempt to flush the mail queue
> is happening before the resolver is able to fulfill its role.
> My suggestion here might help confirm or disprove that.  I hope that
> it helps.

Thanks for the idea.  I will give it a try the next time I do this to
myself.  (I have long since cleaned /var/spool and resent the message.)

In the above case, unless my memory completely fails me, the network was up
and running properly (although that does not preclude the possibility that
there was some issue looking up my particular mail server).  Having said
that, in past cases I tried to encourage postfix by sending other emails
while the stuck one was in the queue, and those emails went happily on
their way.  Which makes me think that postfix is doing something weird with
mail messages that have already failed, as opposed to having issues finding
the server.

Having said that, not having perused the postfix code, I will admit to
having little idea of what is going on inside.

Cheers.
                                   Jim

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Thread

postfix not sending mail in the queue Jim <zsd@jdvb.ca> - 2025-12-16 15:20 -0400
  Re: postfix not sending mail in the queue Rich <rich@example.invalid> - 2025-12-16 23:06 +0000
    Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-22 17:32 -0400
  Re: postfix not sending mail in the queue noel <deletethis@invalid.lan> - 2025-12-17 18:33 +1000
    Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-22 17:34 -0400
      Re: postfix not sending mail in the queue noel <deletethis@invalid.lan> - 2025-12-23 08:12 +1000
        Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-24 20:12 -0400
          Re: postfix not sending mail in the queue Rich <rich@example.invalid> - 2025-12-25 04:25 +0000
            Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-25 11:52 -0400
          Re: postfix not sending mail in the queue Sylvain Robitaille <syl@therockgarden.ca> - 2025-12-25 23:37 +0000
            Re: postfix not sending mail in the queue Sam <sam@email-scan.com> - 2025-12-25 20:34 -0500
              Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-27 13:11 -0400
                Re: postfix not sending mail in the queue Sam <sam@email-scan.com> - 2025-12-28 07:57 -0500
                Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-29 20:32 -0400
                Re: postfix not sending mail in the queue Sam <sam@email-scan.com> - 2025-12-31 08:17 -0500
                Re: postfix not sending mail in the queue jayjwa <jayjwa@atr2.ath.cx.invalid> - 2025-12-31 13:03 -0500
                Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-31 16:14 -0400
                Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-31 16:36 -0400
                Re: postfix not sending mail in the queue noel <deletethis@invalid.lan> - 2026-01-01 23:00 +1000
                Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2026-01-02 12:05 -0400
                Re: postfix not sending mail in the queue Sam <sam@email-scan.com> - 2026-01-02 19:37 -0500
                Re: postfix not sending mail in the queue Rich <rich@example.invalid> - 2026-01-01 15:46 +0000
                Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2026-01-02 17:35 -0400
            Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-27 13:04 -0400
          Re: postfix not sending mail in the queue noel <deletethis@invalid.lan> - 2025-12-26 12:13 +1000
            Re: postfix not sending mail in the queue Jim <zsd@jdvb.ca> - 2025-12-27 13:17 -0400
              Re: postfix not sending mail in the queue Rich <rich@example.invalid> - 2025-12-28 05:19 +0000
                Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-28 23:10 -0400
                Re: postfix not sending mail in the queue Rich <rich@example.invalid> - 2025-12-29 18:06 +0000
                Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-29 20:34 -0400
                Re: postfix not sending mail in the queue noel <deletethis@invalid.lan> - 2025-12-30 10:53 +1000
  Re: postfix not sending mail in the queue jayjwa <jayjwa@atr2.ath.cx.invalid> - 2025-12-17 11:22 -0500
    Re: postfix not sending mail in the queue noel <deletethis@invalid.lan> - 2025-12-18 14:11 +1000
      Re: postfix not sending mail in the queue Henrik Carlqvist <Henrik.Carlqvist@deadspam.com> - 2025-12-18 06:32 +0000
        Re: postfix not sending mail in the queue Marco Moock <mm@dorfdsl.de> - 2025-12-18 16:32 +0100
          Re: postfix not sending mail in the queue Henrik Carlqvist <Henrik.Carlqvist@deadspam.com> - 2025-12-19 18:46 +0000
        Re: postfix not sending mail in the queue noel <deletethis@invalid.lan> - 2025-12-19 12:29 +1000
    Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-22 17:42 -0400
      Re: postfix not sending mail in the queue Sylvain Robitaille <syl@therockgarden.ca> - 2025-12-24 22:34 +0000
        Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-24 20:14 -0400
  Re: postfix not sending mail in the queue Joseph Rosevear <Mail@JoesLife.org> - 2025-12-19 07:54 +0000
    Re: postfix not sending mail in the queue Jim Diamond <zsd@jdvb.ca> - 2025-12-22 18:03 -0400

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