Subject: Discard vs. DSN

From: Randall Gellens <[email-masked]>
Date: Tue, 16 Mar 1999 12:29:24 -0800

If 'discard' MUST NOT cause failure DSN generation, this could be difficult
in certain plug-in environments (such as one of the platforms where my
Sieve implementation runs).

We can either (1) make 'discard' optional, (2) say that 'discard' SHOULD
NOT cause failure DSN generation, or (3) say this is just Too Bad.

Personally, I suggest (2).

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From: Tim Showalter <[email-masked]>
Date: 17 Mar 1999 14:51:49 -0500

> Date: Tue, 16 Mar 1999 12:29:24 -0800
> From: Randall Gellens <[email-masked]>
> 

I am in favor of (3).  Generating DSNs in some cases, most specifically
spam, is not a good idea.

I guess this comes down to a model of what Sieve does.  Randy sees it as 
modifying disposition of a message; I see it as a good deal more
general.

(1) is a very unexpected choice, but if I can't get (3), I think I like
it as much as (2).  At least the behavior is consistant.

-- 
Tim Showalter <[email-masked]>

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From: Ned Freed <[email-masked]>
Date: Wed, 17 Mar 1999 14:26:41 -0800 (PST)

> spam, is not a good idea.

I also favor (3) over the alternatives.

> it as much as (2).  At least the behavior is consistant.

Again I agree; I don't like either (1) or (2) much, but if I had to have one
of them I don't particularly care which one I'd get.

				Ned

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From: Randall Gellens <[email-masked]>
Date: Wed, 17 Mar 1999 20:10:24 -0800

>spam, is not a good idea.

I don't understand this.

In one particular environment where my Sieve implementation runs, 'discard'
causes the same action as if the message is undeliverable for any other
reason (a failure DSN for 'other' is generated).  Why is this bad
specifically in the case of spam?  It doesn't indicate the address is
valid, since there are several reasons why the server might have accepted
the message (such as being an MX for another host).

>modifying disposition of a message; I see it as a good deal more

How does a requirement for silent discard follow from purposes for Sieve
other than message disposition?  Discard *is* message disposition,
regardless of any other uses for Sieve (and I use Sieve for message
annotation as well as disposition).

>it as much as (2).  At least the behavior is consistant.

(1) is what was suggested at the Sieve BOF when I mentioned the issue.  I'm
not especially fond of it.

---

From: Tim Showalter <[email-masked]>
Date: 23 Mar 1999 15:27:02 -0500

> >> [Randy:]
> >> If 'discard' MUST NOT cause failure DSN generation, this could be
> >> difficult in certain plug-in environments (such as one of the
> >> platforms where my Sieve implementation runs).
> >> 
> >> We can either (1) make 'discard' optional, (2) say that 'discard'
> >> SHOULD NOT cause failure DSN generation, or (3) say this is just
> >> Too Bad.
> >
> >[Tim:]
> [Randy:]
> specifically in the case of spam?

Because the message is probably undeliverable, so a failure notice has
to be sent.  This is inconvienent if the failure can be considered
permenant, but is worse if the domain is valid and fails with a
temporary failure somewhere and just hangs around for five days in the
queue.  (Consider what might happen if a shared filter was in use at CMU
and someone spammed our passwd file.)

Does this help?

> annotation as well as disposition).

I don't follow this at all.  Perhaps my statement was poorly worded or
poorly thought out.

My thought is that your implementation seems to only control where a
message gets sent, in addition to actions that may be unrelated to
delivery.  This annoys me because it seems to limit both discard and
multiple fileinto, things well-known existing systems (say, procmail)
are capable of and that I consider useful.

Let me ask this: if discard sends a DSN, how is it meaningfully
different from reject?  Reject seems to present a strict superset of
discard functionality as you've described it (you get to tell the sender
where to go in addition to refusing the message).

I'd like discard so, say, I can ignore certain people.  I don't want to
reject their mail, I just want to ignore it.

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From: Ned Freed <[email-masked]>
Date: Tue, 23 Mar 1999 12:31:11 -0800 (PST)

> reject their mail, I just want to ignore it.

Exactly right. In my experience being able to ignore messages is one of most
commonly requested features, if not *the* most requested feature, for filters
to be able to do. 

This is why I'm strongly opposed to making it optional.

				Ned

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From: Steve Hole <[email-masked]>
Date: Wed, 24 Mar 1999 08:15:31 -0700

> reject their mail, I just want to ignore it.

This is very well said and I agree with it completely.   The functionality
difference seems both clear and useful to me.     Discard shouldn't be 
optional and it should silently throw away the message.

Cheers.

---  
Steve Hole                           
Execmail Inc.
Mailto:[email-masked] 
Phone: 780-424-4922