Modify where sieve scripts are saved.
I recently found out, that if you use some external program to modify sieve scripts on a dovecot install, it does overwrite the sieve filters that are setup through ispconfig3 ( for example using Horde webmail with Ingo filters through dovecot managesieve protocol ). I have found a solution , by doing the following :
Modify maildeliver_plugin.inc.php :
change $sieve_file = $data["new"]["maildir"].'/.sieve';
to : $sieve_file = $data["new"]["maildir"].'/ispconfig.sieve';
Modify dovecot.conf :
Find : sieve=/var/vmail/%d/%n/.sieve Add below : sieve_dir =/var/vmail/%d/%n/ sieve_before =/var/vmail/%d/%n/
What this does is - sets the sieve dir to the dir above Maildir. Before executing the .sieve script it executes every .sieve script in this directory. When ispconfig3 is writing to ispconfig.sieve, it doesn't get overwritten by Ingo for example, because ingo writes to ingo.sieve.