I have found that dovecot probably has some problems with regexp in sieve scripts... Everything is fine until I enter a mail rule which includes some characters that need escaping, like "[". The ISPConfig correctly escapes it and for rule which includes "[Test" in the Subject header it generates a script like this: ### BEGIN FILTER_ID:2 if header :regex ["subject"] [".*\[Test"] { fileinto "Test"; stop; } ### END FILTER_ID:2 but then when I try to send an email to this mailbox, I'm getting this error : main_script: line 34: error: invalid regular expression for regex match: unmatched [ or [^. main_script: error: validation failed. even though the regular expression is perfectly fine. Any ideas on how to fix this? Can anyone test if it works for them hence if it's just a problem with the dovecot version I'm running? The server is Debian 6 with Dovecot 1.2.15
Well after a bit of testing I found that special characters (or at least the square bracket, I haven't tried anything else yet) have to be double escaped, so my filter from the previous message should go like this: ### BEGIN FILTER_ID:2 if header :regex ["subject"] [".*\\[Test"] { fileinto "Test"; stop; } ### END FILTER_ID:2 However you need to manually edit the filter in the "custom rules" tab, because if you enter \[ in the mail filtering tab as a rule, it will get triple escaped (it will become \\\[ in the filter). I'm not sure if it's a bug in the dovecot's sieve plugin implementation of regular expressions or if this is how it should work. If it's a correct behaviour, it needs to be fixed in ISPConfig so that special characters will get double escaped.
