Wietse Venema:
> Look in your LOGS.
>
> http://www.postfix.org/DEBUG_README.html#logging
In particular, logs that the message is handled by your filter,
to eliiminate basic mistakes.
Wietse
> Look for obvious signs of trouble
> =================================
> Postfix logs all failed and successful deliveries to a logfile.
>
> When Postfix uses syslog logging (the default), the file is usually
> called /var/log/maillog, /var/log/mail, or something similar; the
> exact pathname is configured in a file called /etc/syslog.conf,
> /etc/rsyslog.conf, or something similar.
>
> When Postfix uses its own logging system (see MAILLOG_README), the
> location of the logfile is configured with the Postfix maillog_file
> parameter.
>
> When Postfix does not receive or deliver mail, the first order of
> business is to look for errors that prevent Postfix from working
> properly:
>
> % egrep '(warning|error|fatal|panic):' /some/log/file | more
>
> Note: the most important message is near the BEGINNING of the output.
> Error messages that come later are less useful.
>
> The nature of each problem is indicated as follows:
>
> - "panic" indicates a problem in the software itself that only a
> programmer can fix. Postfix cannot proceed until this is fixed.
>
> - "fatal" is the result of missing files, incorrect permissions,
> incorrect configuration file settings that you can fix. Postfix
> cannot proceed until this is fixed.
>
> - "error" reports an error condition. For safety reasons, a Postfix
> process will terminate when more than 13 of these happen.
>
> - "warning" indicates a non-fatal error. These are problems that
> you may not be able to fix (such as a broken DNS server elsewhere
> on the network) but may also indicate local configuration errors
> that could become a problem later.
>
