Subject: MTA Filters BOF request, LA IETF; Proposed Charter

From: "Matthew Wall" <[email-masked]>
Date: Mon, 12 Jan 1998 16:01:55 -0500

We did a general heads-up at the DC IETF, and my belief is there's
sufficient consensus that a WG is justified for MTA Filters and we can move
towards a standards-track proposal. Given that some of us will have "IETF
Cycles" freed up (no pun intended, Ned) with the ACAP work winding down, and
there are already a couple of SIEVE implementations in the works, this seems
like a good time to move with all due consideration.

I'm requesting a slot for either a BOF or a WG (preferred) at LA in March.
In the meantime, we should probably start work on a charter, and hear out
any discussion to the contrary. My draft of a charter is below.

I don't participate directly in any of the SPAM groups. Can somebody more
active in those areas cross-post this as a heads up? One really desirable
thing here is to get better general awareness in the SPAM activity of SIEVE
(including, very importantly, its scope limitations with respect to spam, so
we don't waste any time unnecessarily on turf issues).

- Matt

-----

Working Notes for a Proposed Charter:

Name: MTA Filters

Acronym: MTA-FILT [I'd considered suggesting MTAFILTH -- there's an 8-char
limit on acronyms -- short for MTA Filters on Headers, but in addition to
this possibly being confusing for the sake of cuteness, I didn't think the
acronym would be wildly popular given that it may be confused with
content-based filtering 8-(. Any other suggestions, please make them now].

Chair(s):

TBD. [Matt Wall <[email-masked]> and Ned Freed <[email-masked]> {have
been proposed as co-chairs.]

Applications Area Director(s): 

Keith Moore <[email-masked]>
Harald Alvestrand <[email-masked]>

Applications Area Advisor: 

(proposed) Keith Moore <[email-masked]>

Mailing List Info:

A mailing list was established Jan. 11, 1997, and has been in continuous
existence since.

General Discussion: <mailto:[email-masked]>

Subscribe requests:

<mailto:[email-masked]>

Archive (hyperarchive and FTP):

<http://www.imc.org/ietf-mta-filters/>

Description of Working Group: 

A variety of delivery-time mechanisms for filtering and disposing of
messages have long been available for messages delivered via SMTP. Such
filtering schemes have become increasingly important with the advent of
increased volumes of mail and newer Internet-standard mail access models
with richer delivery capabilities. In this increasingly complex delivery
loop, it is desirable to have an architecture-independent, interoperable
filtering language for use in the MTA delivery process written and adopted
as an Internet Standard.

The working group will specify a simplified but generalizable mail filtering
language for filtering messages at the time of final delivery.  It is
designed to be independent of protocol, though clearly appropriate to
RFC822/821 message handling, and implementable on either a mail client or
mail server, though specifically intended for MTA delivery-side
functionality.  It is meant to be extensible, simple, and independent of
access protocol, mail architecture, and operating system.

Because there has been considerable past work on specific MTA Filtering
proposals, specifically the SIEVE draft, and there is a considerable body of
working implementation experience in this area, the proposed Working Group
anticipates fully completing the proposed Internet Standard in a relatively
timely manner as reflected in the goals and milestones.

Goals and Milestones:

[Past work: IMAP-related MTA Filtering BOF meetings at 1st and 2nd
International IMAP meetings, Seattle, January 1996 (15 attendees) and
November 1996, Seattle (about 25 attendees); Beer BOF discussion, Montreal
IETF, June 1996; informal BOF at San Jose IETF, December 1996 (about 20
attendees); mailing list established, Jan 11, 1997; 1st internet draft of
SIEVE (00), April 22, 1997; 2nd draft (01) June 29, 1997; 3rd draft (02)
(see reference below) October 24, 1997; informal discussion, DC IETF,
December, 1997.]

March 1998      Meet at LA IETF to finalize concepts, functionality, scope,
and to review current SIEVE draft proposal, and to define what (if any)
additional work is required by the WG to meet the functional goals in the
charter.

May 1998        Submit 4th draft of SIEVE draft proposal.

August 1998     Meet at Chicago IETF to discuss current draft and related
work.

October 1998    Submit final Internet Draft(s) to IESG for consideration as
Proposed Standard.

Internet-Drafts: 

ftp://ds.internic.net/internet-drafts/draft-showalter-sieve-02.txt

[VACATION Extension -00 draft, not yet submitted to secretariat]:

http://www.club.cc.cmu.edu/~tjs/sieve-vacation.txt

---

From: Keith Moore <[email-masked]>
Date: Mon, 12 Jan 1998 16:51:02 -0500

Matt,

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.

in addition, the notion of a "general" filtering language,
as opposed to one specifically designed for email, sounds
like a rathole to me.

Keith

---

From: Ned Freed <[email-masked]>
Date: Mon, 12 Jan 1998 14:23:32 -0800 (PST)

> business, but then it's a UA-level thing.

Sometimes it is, sometimes it isn't. The point of the exercise is to define
something that can be used anywhere in the process. As such, calling it "MTA
filtering" may not be a good idea. But that doesn't mean the idea is bad.

Ideally filtering will be done at the same time final delivery is done.
Circumstances conspire, however, to sometimes make it necessary to do filtering
at other times. For example, a large ISP may wish to promote user filtering
settings to their outermost MTA so as to avoid the overhead of processing
messages that will later be dropped. Or it may be necessary for a user agent to
implement filtering as part of its internal processing after final delivery
because it cannot count on it being done prior to that point.

> as opposed to one specifically designed for email, sounds

I disagree. I think we've made reasonable progress on defining a language and
are likely to be able to reach consensus on it. I also think this, like
firewalls, is one of those issues that the IETF ignores at its peril.

In any case, I would like to try this and see if we can get somewhere.

				Ned

---

From: Tim Showalter <[email-masked]>
Date: 12 Jan 1998 19:17:56 -0500

> From: Keith Moore <[email-masked]>
> Date: Mon, 12 Jan 1998 16:51:02 -0500
> 
> Matt,
> 

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 [email-masked]
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
necessary.

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.

> as opposed to one specifically designed for email, sounds

"General" is too general.  Sieve is designed for e-mail, and that's the
intent of the proposed WG.

-- 
                                           Tim Showalter [email-masked]