Subject: Re: too many "Out of Office AutoReply"

From: "Steven M. Bellovin" <[email-masked]>
Date: Fri, 29 Jun 2001 09:30:56 -0400

Thanks for the note -- I'll resist the temptation to have procmail 
forward a copy of your instructions to anyone whose mailer sends such
a note to the IETF list.

But I'm disturbed that Exchange is using the Precedence: line as its 
selector mechanism.  I'm hardly an email expert, but a quick grep 
through the RFCs turned up exactly one mention of the Precedence: 
header line.  That reference is in 2076, which describes it as 
"Non-standard, controversial, discouraged".  No RFC definition is cited.
It would be nice if such an important feature relied only on 
standardized headers.

		--Steve Bellovin, http://www.research.att.com/~smb

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From: Paul Hoffman / IMC <[email-masked]>
Date: Fri, 29 Jun 2001 09:02:37 -0700

>It would be nice if such an important feature relied only on

Steve, we'll forgive you for not being an email expert. If you were 
one, you would know that this topic, and half a dozen of related 
meta-topics, have been beaten to death in the (finally dead!) DRUMS 
WG, and on the ietf-822 mailing list in the past six or seven years. 
A summary is that some implementations prefer to be strictly 
standards-compliant but piss off their users by not doing enough, 
while others choose to do things the users want even though it 
doesn't go strictly by the standards. In this case, there are 
non-standard headers in common use that give valuable heuristics to 
programs, and no standard ones that give the same information. Many 
companies, apparently including Microsoft, use that non-standard 
information.

--Paul Hoffman, Director
--Internet Mail Consortium

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From: Lloyd Wood <[email-masked]>
Date: Fri, 29 Jun 2001 18:18:03 +0100 (BST)

On Fri, 29 Jun 2001, Paul Hoffman / IMC wrote:

> In this case, there are 

So standardise them already.

L.

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From: John C Klensin <[email-masked]>
Date: Fri, 29 Jun 2001 13:23:15 -0400

--On Friday, 29 June, 2001 09:02 -0700 "Paul Hoffman / IMC"
<[email-masked]> wrote:

> Steve, we'll forgive you for not being an email expert. If you
> were  one, you would know that this topic, and half a dozen of
> related  meta-topics, have been beaten to death in the
> (finally dead!) DRUMS  WG, and on the ietf-822 mailing list in
> the past six or seven years.  A summary is that some
> implementations prefer to be strictly  standards-compliant but
> piss off their users by not doing enough,  while others choose
> to do things the users want even though it  doesn't go
> strictly by the standards. In this case, there are 
> non-standard headers in common use that give valuable
> heuristics to  programs, and no standard ones that give the
> same information. Many  companies, apparently including
> Microsoft, use that non-standard  information.

Paul, while I generally agree with your description of the
problem, we _do_ have a standard in this case.   RFC 2919
specifies some list-specific special headers.  From episodic
examinations of messages arriving here from various lists, it
has gotten reasonably well implemented, almost certainly enough
so to  promote it to Draft Standard if someone does the work in
the next few months.   And nothing prevents a receiving MTA from
observing the presence of those fields and using that
information to suppress vacation/ out-of-office messages even
if, for historical reasons, they also consider Precedence fields
(or whatever).

   john

---

From: Keith Moore <[email-masked]>
Date: Fri, 29 Jun 2001 13:51:42 -0400

> companies, apparently including Microsoft, use that non-standard

Extension header fields are explicitly permitted by the standards, and
(for better or worse) other vacation programs also recognize the 
Precedence field.  So it's unfair to single out Microsoft for 
using it also.  But although the heuristic is widely used, it 
has never been considered sufficient.

Keith

p.s. there are a lot of problems with Precedence, not the least of
which are that it is used for at least 5 different things by different
mail packages: for influencing queueing priority, deciding whether 
to return content in nondelivery reports, deciding whether to return
a vacation message, indication of message importance, and as a loop 
prevention sentinel by mailing list software.  There are probably others.
Most of these uses do not conflict with one another, but occasionally 
they do.  It's not exactly a robust mechanism.

---

From: Paul Hoffman / IMC <[email-masked]>
Date: Fri, 29 Jun 2001 10:56:34 -0700

At 1:23 PM -0400 6/29/01, John C Klensin wrote:
>specifies some list-specific special headers.

Correct. That standard was issued after all of the SMTP servers in 
question were released. (For those of you who don't want to look in 
the RFC archive, that RFC was issued in March 2001.)

>   From episodic
>the next few months.

But, of course, that won't help in the current case, because this 
list doesn't use the standard.

--Paul Hoffman, Director