From: Keith Moore <moore(_at_)cs(_dot_)utk(_dot_)edu>
Date: Mon, 12 Jan 1998 16:51:02 -0500
I'm very dubious about the desirability of standardizing an
MTA-level mail filtering language.
with few exceptions, the mail transport system should not be
doing mail filtering. the mail transport's job is to deliver
mail, not to make filtering decisions on behalf of the user.
if recipients want to filter their own mail, that's their
business, but then it's a UA-level thing.
Perhaps "MTA-level" is a poor choice of term.
The language is intended to be used by UAs to configure the delivery agent
in between the MTA and the message store. (The
list contains a long discussion on exactly which interpretation of "MTA" is
being used; I guess MTA is ambiguous at best.) It's intended for users to
use to give a script to the delivery agent to do whatever filtering is
It's intended to fill the same role as procmail, but be less reliant on
assumptions of Unix mail and file systems, provide a standard syntax, and
let usable UAs generate scripts to configure filters.
Specifically, In the case of IMAP, it's reasonable and desirable to filter
mail at delivery time instead of at the UA's whim. In POP, throwing out
messages while they're still on the POP server could also be useful for
users trying to junk unwanted mail.
in addition, the notion of a "general" filtering language,
as opposed to one specifically designed for email, sounds
like a rathole to me.
"General" is too general. Sieve is designed for e-mail, and that's the
intent of the proposed WG.