Subject: RE: bounce, mta, & mua (was Re: sieve draft)

From: "Woodhouse, Gregory J." <[email-masked]>
Date: Wed, 5 Nov 1997 11:17:25 -0600

Indeed. I'm a big fan of procmail, but I always warn people (maybe to 
excess) to be very careful when first setting up procmail and to get 
someone to help them through the process if at all possible. I don't 
know if mail filtering with any sort of rewrite capability can be made 
"safe" in this sense. (Sorry, if I miss the point here - I've been 
unable to study sieve in detail just yet because of other fires). 
Perhaps an informational RFC listing caveats for implementing mail 
filtering would be in order.

===
Gregory Woodhouse
San Francisco CIO Field Office - Infrastructure
[email-masked]
+1 415 744 6362

----------
From:  Tim Showalter [SMTP:[email-masked]]
Sent:  Wednesday, November 05, 1997 1:03 AM
To:  Tomas Fasth
Cc:  MTA Filters
Subject:  Re: bounce, mta, & mua (was Re: sieve draft)

[...]

Procmail has done a fairly decent job and presents roughly the same 
dangers,
and I think it has even more potential to shoot users in the feet. 
 But I
haven't used it, and haven't even looked at the documentation much...

[...]

---

From: "Woodhouse, Gregory J." <[email-masked]>
Date: Wed, 19 Nov 1997 12:47:15 -0600

Actually, RFC 822 (at least) never says "Return-Path" is required, but 
the revised document being developed by DRUMS reads:
When the delivery SMTP server makes the "final delivery" of a message, 
it inserts a return-path line at the beginning of the mail data.  This 
use of return-path is required; mail systems MUST support it.  The 
return-path line preserves the information in the <reverse-path> from 
the MAIL command.  Here, final delivery means the message has left the 
SMTP world.  Normally, this would mean it had been delivered to the 
destination user or an associated mail drop, but in some cases it may 
be further processed and transmitted by another mail system.
===
Gregory Woodhouse
San Francisco CIO Field Office - Infrastructure
[email-masked]
+1 415 744 6362  /  May the dromedary be with you

----------
From:  Tomas Fasth [SMTP:[email-masked]]
Sent:  Wednesday, November 19, 1997 8:07 AM
To:  [email-masked]
Subject:  Re: bounce, mta, & mua (was Re: sieve draft)

Chris Newman wrote:
> This is incorrect.  UAs will have access to the "MAIL FROM" address 
unless
> an upstream system violated Internet standards.  The final delivery 
agent
> is REQUIRED to copy the "MAIL FROM" address into the "Return-Path"
> header.  Anything which doesn't is broken.

Chris, can you give us the exact location in an RFC that backs up your 
assertion? I'm not sure it is required and I'm not sure you can ever 
rely on it's existence once the message have moved into the domain of 
the MUA.
If you're right, my FreeBSD "out-of-the-box" installation is certainly 
broken. The "P" flag required to generate the Return-Path header is 
_not_ set for the local mailer by default. I don't know why, but the 
very existence of this discrepency (the fact that it's optional) is 
enough for me to maintain that this header might not always be 
available. Period.

[...]
--
Hälsningar/Regards
Tomas Fasth <[email-masked]>
Tel: +46-13-218-181 Cel: +46-708-870-957 Fax: +46-708-870-258 
EuroNetics Operation, Mjärdevi Science Park, 58330 Linköping, Sweden 
(TwinSpot Network is a subsidiary of EuroNetics Operation)