Spam Reporting

Spam/not-spam reporting within Dovecot (IMAP) is handled by the user action of moving a message into (or out of) a defined Spam mailbox.

The Spam mailbox is defined and reported to the MUA via a Special-Use flag:

namespace inbox {
  mailbox Spam {
    auto = create
    special_use = \Junk
  }
}

Spam reporting messages are handled via imapsieve plugin. A global configuration script is used to capture the event of moving messages in/out of the Spam mailbox; the script sends the message using RFC 5965 compliant spam reporting format to an external reporting e-mail address, using the report extension.

protocol imap {
  mail_plugins = $mail_plugins imap_sieve
}

plugin {
  sieve_plugins = sieve_imapsieve
  sieve_implicit_extensions = +vnd.dovecot.report

  # From elsewhere to Spam folder
  imapsieve_mailbox1_name = Spam
  imapsieve_mailbox1_causes = COPY
  imapsieve_mailbox1_before = file:/etc/dovecot/report-spam.sieve
  # From Spam folder to elsewhere
  imapsieve_mailbox2_name = *
  imapsieve_mailbox2_from = Spam
  imapsieve_mailbox2_causes = COPY
  imapsieve_mailbox2_before = file:/etc/dovecot/report-ham.sieve
}

# Needed to send message to external mail server
submission_host = 127.0.0.1:587

report-spam.sieve:

require "vnd.dovecot.report";

report "abuse" "User added this message to the Spam folder." "spam-report@example.com";

report-ham.sieve:

require "vnd.dovecot.report";
require "environment";
require "imapsieve";

if environment "imap.mailbox" "Trash" {
   # Putting spam in Trash mailbox is not significant
   stop;
}

if environment "imap.mailbox" "Spam" {
   # Copying mail inside Spam mailbox is not significant
   stop;
}

report "not-spam" "User removed this message from the Spam folder." "ham-report@example.com";

See also

Replacing antispam plugin with IMAPSieve