This documentation is for Dovecot v1.x, see wiki2 for v2.x documentation.
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The real error message is written to Dovecot's log file. The timestamp is meant to help you find it. The point is that whenever anything unexpected happens, Dovecot doesn't leak any extra information about it to clients. They don't need it and they might try to exploit it in some ways, so the less they know the better.

The real error message is written to the error log file. The timestamp is meant to help you find it.

TableOfContents

Dovecot Logging

By default Dovecot starts logging to syslog using mail facility. In most operating systems this goes to/var/log/mail.log, /var/log/maillog or something similar. If there is anything wrong with your configuration or if something crashes, Dovecot will always log the error message. It's extremely rare that Dovecot dies without giving any sort of error message, so make sure you're looking at the correct log file.

NOTE: Error messages may be logged into a different log file than the informational log lines! Some syslogs are by default configured to log mail error messages into a different log file.

After you start Dovecot, make sure that you can find a line similar to this:

dovecot: Jan 07 14:22:40 Info: Dovecot v1.0.rc19 starting up

However, the above message is logged into informational log, which may or may not be where the error messages are logged.

In 1.0.rc20 and later, you can use dovecot --log-error command line option to find the error log. It will log a line:

dovecot: Jan 27 03:44:21 Fatal: This is Dovecot's error log

Internal Errors

If IMAP or POP3 processes encounter some error, they don't show the exact reason for clients. Instead they show:

Internal error occurred. Refer to server log for more information. [2006-01-07 22:35:11]

The point is that whenever anything unexpected happens, Dovecot doesn't leak any extra information about it to clients. They don't need it and they might try to exploit it in some ways, so the less they know the better.

The real error message is written to the error log file. The timestamp is meant to help you find it.

Changing Log File Paths

If you don't want to use syslog, or if you just can't find the Dovecot's error logs, you can make Dovecot log elsewhere as well:

log_path = /var/log/dovecot.log
# If you want everything in one file, just don't specify log_info_path
log_info_path = /var/log/dovecot-info.log

The error messages will go to file specified by log_path, while everything else goes to log_info_path. If you do this, make sure you're really looking at the log_path file for error messages, since the "Starting up" message is written to log_info_path file.

Rotating Logs

If you change from syslog to an external log file, you can use logrotate (available on most recent linux distros) to maintain the Dovecot logfile so it doesn't grow beyond a manageable size. Save the below scriptlet as /etc/logrotate.d/dovecot:

# dovecot SIGUSR1: Re-opens the log files.
/var/log/dovecot*.log {
  missingok
  notifempty
  delaycompress
  sharedscripts
  postrotate
    /bin/kill -USR1 `cat /var/run/dovecot/master.pid 2>/dev/null` 2> /dev/null || true
  endscript
}

NOTE: change the path to the logfile(s) and the master.pid file as appropriate for your system configuration.

None: Logging (last edited 2009-10-28 03:05:44 by TimoSirainen)