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Re: [ietf-dkim] Alternative MAiling List Approach

2010-07-29 17:49:56
-----Original Message-----
From: ietf-dkim-bounces(_at_)mipassoc(_dot_)org [mailto:ietf-dkim-
bounces(_at_)mipassoc(_dot_)org] On Behalf Of Charles Lindsey
Sent: Thursday, July 29, 2010 4:22 AM
To: ietf-dkim(_at_)mipassoc(_dot_)org
Subject: [ietf-dkim] Alternative MAiling List Approach

The REAL cause of the problem is that From: line. My proposal is that
MLM
should change the From: header in such a way that the mail appears to
have
come from MLM.example and not from discardable.example. Clearly, this
removes the cause of the problem at a stroke (the mail will no longer
be
discarded), but obviously it raises several other issues instead.

Chiefly, list subscribers (such as client(_at_)somewhere(_dot_)example) will 
not
immediately see who the mail is from, and will not be able to reply
directly to joe(_at_)discardable(_dot_)example(_dot_) There are several 
things that
would
need to be done to mitigate this:

1. Preserve in  an X-Old-From: joe(_at_)discardable(_dot_)example (but mailing
agents
will tend not to display that header).

2. Add a Reply-To: joe(_at_)discardable(_dot_)example (unless Joe had already
supplied his own Reply-To:, or mailing list policy is to set Reply-To
to
point back to the list).

3. Preserve any <display-name> in the modified From: e.g.
        From "Joseph" <something(_at_)MLM(_dot_)example>

4. Somehow encode the original joe(_at_)discardable(_dot_)example within the
revised
From: header, preferably in such a way that replies will still get back
to
Joe.

And it is #4 which is really going to solve the problem, though #1-3
should still be applied as backup measures that will assist the
confused
recipient.

So how to encode the old address within the new? Here is my proposal:

        From: "Joseph" <joe%discardable(_dot_)example(_at_)MLM(_dot_)example>

Which is, of course, the old (discredited?) "percent hack". But here
used
in a safely controlled environment.

It looked to me that a couple of people agreed with this.  That's far from 
consensus but it indicates a question that should be posed:

Should the MLM draft suggest From: replacement and addition of Reply-To: as a 
specific example of DKIM-friendly MLM behavior?

Those things could be deployed by only touching MLMs; Charles' #4 above would 
also require MUA and/or general MTA co-operation, so it's probably too 
ambitious for this effort.

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