Strange behavior

[Michael Brunnbauer]

hi all,

does a log file entry

delivery 40846: deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/

mean that there was an actual delivery attempt?

The other server was temporarily down but the problem was already fixed.

Sending new mail to this server or an ALRM signal to qmail-send caused these
messages to appear in the log without any IP packet going out to the
destination server via the network (I checked with tcpdump). It seems that
qmail did not even try to reach the server. After a while, the mails went
through.

Regards,

Michael Brunnbauer
--
++ Michael Brunnbauer
++ netEstate GmbH
++ Geisenhausener Straße 11a
++ 81379 München
++ Tel [phone]
++ Fax [phone]
++ E-Mail ***@netestate.de
++ http://www.netestate.de/
++
++ Sitz: München, HRB Nr.142452 (Handelsregister B München)
++ USt-IdNr. DE221033342
++ Geschäftsführer: Michael Brunnbauer, Franz Brunnbauer
++ Prokurist: Dipl. Kfm. (Univ.) Markus Hendel

[Andy Bradford]

Post by Michael Brunnbauer
does a log file entry
delivery 40846: deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/
mean that there was an actual delivery attempt?

Yes, it means that qmail attempted to deliver the message (hence an
actual delivery id of 40846) to the SMTP server.

Post by Michael Brunnbauer
The other server was temporarily down but the problem was already
fixed.

If the problem was already fixed, then it would have not had to defer
the delivery. qmail will retry delivery to the server later, and if the
problem has been resolved, then it will deliver successfully and be
removed from the queue.

Andy
--
TAI64 timestamp: 40000000543ffdd5

[Michael Brunnbauer]

Hello Andy,

Post by Andy Bradford

Post by Michael Brunnbauer
does a log file entry
delivery 40846: deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/
mean that there was an actual delivery attempt?

Yes, it means that qmail attempted to deliver the message (hence an
actual delivery id of 40846) to the SMTP server.

Are you sure? I got a pointer to qmail-tcpok from another participant.

qmail-remote reporting "temporary failure" without actually checking because
the destination server is in the current list of timeouts would perfectly
explain what I saw.

Regards,

Michael Brunnbauer
--
++ Michael Brunnbauer
++ netEstate GmbH
++ Geisenhausener Straße 11a
++ 81379 München
++ Tel [phone]
++ Fax [phone]
++ E-Mail ***@netestate.de
++ http://www.netestate.de/
++
++ Sitz: München, HRB Nr.142452 (Handelsregister B München)
++ USt-IdNr. DE221033342
++ Geschäftsführer: Michael Brunnbauer, Franz Brunnbauer
++ Prokurist: Dipl. Kfm. (Univ.) Markus Hendel

[Andy Bradford]

qmail-remote reporting "temporary failure" without actually checking
because the destination server is in the current list of timeouts
would perfectly explain what I saw.

man qmail-tcpto has this to say about it:

After an SMTP connection attempt times out, qmail-remote
records the relevant IP address. If the same address fails
again (after at least two minutes with no intervening
successful connections), qmail-remote assumes that further
attempts will fail for at least another hour.

So qmail must have made at least 2 delivery attempts to the server and
received timeouts. After an hour it would automatically remove the
timeout from the tcpto file and the deliver might have succeeded if the
server is back up.

Andy
--
TAI64 timestamp: 40000000544005ed

[Andy Bradford]

Post by Michael Brunnbauer

Yes, it means that qmail attempted to deliver the message (hence an
actual delivery id of 40846) to the SMTP server.

Are you sure? I got a pointer to qmail-tcpok from another participant.

Yes, you're right, it does consult the tcp timeouts table before trying
to establish a connection. And yes, the fact that it didn't actually
connect to the server doesn't mean a qmail delivery attempt was not made
(it was made, hence the entry in your logs).

Andy
--
TAI64 timestamp: 4000000054400506