Dovecot With DSpam AntiSpam Plugin Replacement With Sieve

[colinh at nxtgn.com]

Hello

I have recently had to rebuild my email server, it is a small server for 
my various email accounts and I also host the email for a clients 
business.

Switched to Dovecot from Courier many years ago, and it has been a very 
reliable solution With the new rebuild I have updated it to Dovecot 
2.2.33.2 with PigeonHole 4.21, it runs DSpam 3.10.2 to scan and tag all 
incoming mails as Spam or not then a Sieve rule to put the Spam emails 
into the Spam folder, I was also using the DSpam Antispam plugin to 
enable moving messages from one folder to another to teach failures to 
DSpam, this works well for my and my client.

Doing the rebuild I saw that the AntiSpam plugin had been deprecated and 
the preferred solution now was to use Sieve Filters, so I implemented 
that and had struggled with it for a few hours until I finally got it 
working.

It may be something about my setup but I am not sure it is, but the 
suggested way of doing it here
https://wiki.dovecot.org/HowTo/AntispamWithSieve did not work for me and 
I don't think  it was ever going to.

Here are the shell scripts and sieve filters that I came up with that 
work for me, your mileage may vary.

I use DSpam as a standalone binary not as a daemon so you may need to 
add the --client option on the dspam command line in the shell scripts 
if you run DSpam in daemon mode.

=== report-spam.sieve ===

require ["vnd.dovecot.pipe", "copy", "imapsieve", "environment", 
"variables"];


if environment :matches "imap.user" "*" {
   set "userid" "${1}";
   if header :matches "X-DSPAM-Signature" "*"
   {
        set "signature" "${1}";
   }
}

pipe :copy "learn-spam.sh" [ "${userid}", "${signature}" ];

=== report-ham.sieve ===

require ["vnd.dovecot.pipe", "copy", "imapsieve", "environment", 
"variables"];

if environment :matches "imap.mailbox" "*" {
   set "mailbox" "${1}";
}

if string "${mailbox}" "Trash" {
   stop;
}

if environment :matches "imap.user" "*" {
   set "userid" "${1}";
   if header :matches "X-DSPAM-Signature" "*"
   {
        set "signature" "${1}";
   }
}

pipe :copy "learn-ham.sh" [ "${userid}", "${signature}" ];

=== learn-spam.sh ===

#!/bin/sh
exec /usr/local/bin/dspam --user ${1} --signature=${2} --class=spam 
--source=error

=== learn-ham.sh ===

#!/bin/sh
exec /usr/local/bin/dspam --user ${1} --signature=${2} --class=innocent 
--source=error


I hope this saves someone some time or gives someone some tips

-- 
Regards

Colin