Thanks to your help Steffen I was able to find out the issue which was simply the size of the Spam mail as you can see here:
spamc[16545]: skipped message, greater than max message size (512000 bytes)
The spam mail was around 900 kbytes as such I have changed the spamc limit to 1MB. Bastard spammer who abuses this limit by attaching a big image...
Regards ML
On Thursday, January 15, 2015 12:23 PM, ML mail mlnospam@yahoo.com wrote: Thank you for your helpful hints on debugging this issue. I wanted first to get the mail which generates this error but unfortunately the user already deleted it as well from his trash. Now I got another hint and it looks like this mail had a big attachment to it. Is it possible that spamc generated this error due to the size of the mail?
Regards ML
On Thursday, January 15, 2015 8:29 AM, Steffen Kaiser skdovecot@smail.inf.fh-brs.de wrote: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
On Thu, 15 Jan 2015, ML mail wrote:
It would be better to have the original question & discussion at the top, so one could cut and read nicely,
On Wednesday, January 14, 2015 9:06 PM, Pascal Volk user+dovecot@localhost.localdomain.org wrote: On 01/14/2015 03:05 PM, ML mail wrote:
Hello,
I am using the antispam plugin of Dovecot with SpamAssassin and in some cases when users move back mails from the Spam folder to their INBOX (false positive) they get the following error message:
[SERVERBUG] failed to send mail
# 2.1.7: /etc/dovecot/dovecot.conf # OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.8 ext4
[cut]
plugin { antispam_backend = pipe antispam_pipe_program = /usr/bin/spamc antispam_pipe_program_args = -d;my-mx-server.domain.com;-u;amavis antispam_pipe_program_notspam_args = -L;ham antispam_pipe_program_spam_args = -L;spam antispam_pipe_tmpdir = /tmp antispam_signature = X-Spam-Flag antispam_signature_missing = error antispam_spam = INBOX.Spam;INBOX.Junk antispam_trash = INBOX.trash;trash;INBOX.Trash;Trash;INBOX.Deleted Items;Deleted Items;INBOX.Deleted Messages;Deleted Messages antispam_verbose_debug = 1
What does the Plugin log?
[cut]
service quota-warning { executable = script /usr/local/bin/quota-warning.sh unix_listener quota-warning { user = vmail } user = vmail }
You seem to use a virtual user configuration, so the antispam plugin executes spamc as user vmail, correct?
What happens if you run the program manually? sudo -u vmail /usr/bin/spamc -d my-mx-server.domain.com -u amavis -L ham \ < message
You can also trace the program with a wrapper script. Replace antispam_pipe_program with /usr/local/bin/spamc-wrapper
==== BEGIN /usr/local/bin/spamc-wrapper #/bin/bash
( # when and who date;id; let i=0 # what echo /usr/bin/spamc "$@" # see embedded spaces in arguments for arg; do let i=i+1 echo "Arg#$i: '$arg'" done # call original program
/usr/bin/spamc "$@" # log return code / exit code rc=$? echo rc=$rc # Make sure the rc is returned back to caller exit $rc
# log everything into a file ) >>/tmp/spamc-wrapper.log 2>&1 ==== END
If you have lots of simultaneous calls, create one log file per call -> add .$$ to filename.
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