dupidmilter - duplicate message-id mail filter module

Fetch the software. Release notes.

Sendmail includes a facility for plugging in custom mail filters, called milters. It's documented here. Dupidfilter is a plug-in that checks whether the message-id has been seen before.

Release Notes

Version 0.50, ??sep2015:


This is very abbreviated, intended mainly as a reminder for those who have worked with milters before. If it's your first milter, you should look on the web for more thorough documentation. Also, these instructions are pretty specific to FreeBSD, and will have to be adapted for other OSs.

  1. Make sure your sendmail is compiled with the MILTER option. (Starting with version 8.13 this is enabled by default.) You can use this command to check:
    sendmail -d0.1 -bt < /dev/null | grep MILTER
    If you don't see MILTER in the compilation options, you will have to re-build sendmail.
  2. Build and install the dupidmilter executable, by doing a 'make ; make install'.
  3. Edit your sendmail.mc and add a mail filter macro, for example:
    Rebuild and install sendmail.cf.
  4. Run dupidmilter, with the same socket argument you used in sendmail.mc:
    # dupidmilter unix:/var/run/dupidmilter.sock
  5. Stop and re-start sendmail.
  6. Look in /var/log/maillog for messages from dupidmilter.
  7. When you've verified that it's working, add lines to your /etc/rc.conf so it starts up at boot time:

See also: spfmilter, blackmilter, graymilter, sfcmilter, sample_milter.
ACME Labs / Software / dupidmilter