[Dovecot] sieve

[Steffen Kaiser]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tue, 6 Nov 2012, Christian Rößner wrote:

>>> but I am looking for a mechanism that can reject Mail. Postfix can
>>> use reject_unverified_recipient to connect to LMTP and ask if a mail
>>> would successfully be enqueued and will return the status gotten from
>>> the LMTP server if not. Chances are high that the mechanism would
>>> work, too, if Dovecot would know about the sieve rule, while getting
>>> a connection on LMTP. Does Dovecot know all rules at this point or is
>>> sieve handled after the mail has already been accepted?

That is actually the point. As far as I know, all MTAs have already 
accepted the message, before they try to deliver it. If delivering fails, 
they queue them for retry.

>> I have no idea if your above idea would actually work, but having
>> followed your questions on the postfix ml and your interests in using
>> reject_unverified_recipient and its cache with lmtp, it would be very
>> unwise to cache deliverability on the postfix side based on sieve
>> results, since sieve is able to reject/bounce on any part of the message
>> including message body contents and such.
>
> yes I know what you mean. The problem is that a user can decide to 
> "reject" not based on "from" leading in rejects to other mails coming in 
> to the same user. Probably a problem.

Dunno about that discussion, did it included messages to multiple 
recipients, of which some reject and some accept the message? In SMTP you 
cannot individually fail a message after DATA phase.

> The idea came up, as I work for a little ISP/ESP here. Sometimes I get calls, where I get asked if I could reject mails from "xyz". And with a robut good working mechanism, where people could reject on their on decisions would make things easier. So I thought about sieve as being a workable solution.
>
> Another solution would be to write some kind of milter/policy-service 
> with a web-interface, where people can reject mails directly on the 
> postfix side. But this is a lot of work.

Look at CanIT / MIMEDefang.

Kind regards,

- -- 
Steffen Kaiser
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)

iQEVAwUBUJjTwGoxLS8a3A9mAQKCuggAnAvnsShCbbEQGDgsR93aIg+Vc1w9HC7m
NKWddvYIXRgTKC0qr6QM4tqkCIrtGVviylp+wFwyI+9ZvLx5t+3f8JFKHg0hO5MM
Sbuu0ZmjCbm9STkNv2xvl72TBh5IWpByeKQt6fJQ5aT1f0Iqxo6i0+/Q0eoi5p82
HDgx27ASAtUqCHf+iPUg8G/FSndxxEcOvrSACn+hLfv71YU2iovgYTZazLt3u4pz
hSWMQkpQyBwCxj75bz6y72sJxyMtd7XOMV5lGHumbSX6jg7WdI/cCScv14d2Uh5S
D6yNya6+WB3AIGFg+NK9LuSz6IBq/eqIJivTGWvljOOIYsONnT8hbg==
=/nYA
-----END PGP SIGNATURE-----