[Mailman-Users] Query about low-level SMTP errors
Steve Burling
srb at umich.edu
Fri Sep 28 15:44:48 CEST 2007
This is really an "is my understanding correct" question...
Our mail server is getting the snot beat out of it by spambots, and even
though I've turned on pretty aggressive connection rate control and
limiting of the number of concurrent connections from any particular bot,
we still occasionally hit sendmail's (configured) limit of 70 child
processes, at which point we start refusing connections for awhile. During
those times, mailman is also refused connections, resulting in errors like
this from smtp-failure:
Log file: smtp-failure
==============================
23 delivery failed with code -1: (111, 'Connection refused')
1 Low level smtp error: (111, 'Connection refused'), msgid:
<mailman.9.1190894402.11108.some-list at icpsr.umich.edu>
1 Low level smtp error: (111, 'Connection refused'), msgid:
<mailman.8.1190894402.11108.some-other-list at icpsr.umich.edu>
Am I correct that Mailman doesn't consider these permanent errors, and will
re-try these attempts later? Nothing seems to be left lying around in the
queue files, so I'm hoping that subsequent retries succeeded, and not that
Mailman just gave up and tossed things. (That doesn't seem likely to me,
but I figured it was better to ask, so I know if I have to spend more time
trying to figure out how to make sendmail only refuse connections on the
non-localhost interface. Although if anyone knows the magic knob to do
that, I would appreciate a hint.)
--
Steve Burling <mailto:srb at umich.edu>
University of Michigan, ICPSR Voice: +1 734 615.3779
330 Packard Street FAX: +1 734 647.8700
Ann Arbor, MI 48104-2910
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