Re: [Mailman-Users] Message-ID required - was: Reply-to options not working

[Dimitri Maziuk]

On 2018-02-06 04:09, Stephen J. Turnbull wrote:


Do you have something to add to that, or disagree with that?


I said it was what *I* believe, not what IETF believes.

Dima


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Re: [Mailman-Users] Message-ID required - was: Reply-to options not working

[Stephen J. Turnbull]

Dimitri Maziuk writes:

 > Heh. I personally believe that a message sent by a mailing list
 > *must* have the mailing list as the originator: dkim, id, and
 > whatever else.

First, please be careful with terminology.  *Originator* is
well-defined (RFC 5598) as the agent of the Author that first injects
the message into the mail system.  When mailing lists distribute posts
to subscribers, they function as *Mediators* (RFC 5598).

Even if used loosely, I see no reason here to think of mailing lists
as "originators".  DKIM explicitly provides that multiple signatures
may be present, whether from the same host or different hosts.  For
message identification, Mediators are encouraged to use
Resent-Message-ID and other Resent-* fields to provide trace
information in addition to the MTA's Received fields.  Such features
are available to any agent in the mail system, not restricted to
Authors and Originators.

 > And even if "Message-ID MUST be present and MUST be unique", that
 > doesn't make the converse true: that two copies of the same message
 > *must* carry the same Message-ID.

I don't understand your point.  The RFCs make clear that in the case
of certain trivial modifications (adding trace fields to the header,
for example), the Message-ID SHOULD be preserved.  Further, Mark has
described when Mailman will alter the Message-ID, and I described some
of the cases where people disagree about whether to alter it.

However, for stock Mailman, I think that pretty much everybody who
cares about Message-ID agrees that given the kinds of changes Mailman
makes to messages, it should only change Message-ID in an overriding
case such as preserving privacy on a list that purports to anonymize
posts, or where it interferes with interoperability.  Otherwise you
interfere with features such as local duplicate suppression,
threading, and archiving that depend on stability of Message-ID.

Do you have something to add to that, or disagree with that?

Steve
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Re: [Mailman-Users] Message-ID required

[Stephen J. Turnbull]

Mark Sapiro writes:
 > On 02/05/2018 12:22 AM, Stephen J. Turnbull wrote:
 > > 
 > > According to RFC, Message-ID is an originator field, and MUST be
 > > present and MUST be unique.
 > 
 > Do you have a reference for this? I thought this was correct, but I
 > recently looked it up in RFC 5322 and predecessors and those RFCs
 > at least say it's optional and SHOULD be present.

You're right.  I knew that it was SHOULD in RFC 822, but I thought
this was updated in RFC 1123 "Host Requirements" or maybe RFC 5598
"Email Architecture".  I was wrong.

In any case, SHOULD is pretty close to MUST, especially in this case.
(What reasons based on interoperability issues can you think of for
omitting Message-ID?  SHOULD means you need one!)

I'm guessing that since the RFC authors have deprecated use of
Message-ID for anything related to security, and its semantics are a
judgment call in any case, it's simply not reliable enough to promote
to MUST.  So they never did.

Steve

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Re: [Mailman-Users] Message-ID required - was: Reply-to options not working

[Dimitri Maziuk]

On 02/05/2018 11:55 AM, Mark Sapiro wrote:
> On 02/05/2018 12:22 AM, Stephen J. Turnbull wrote:
>>
>> According to RFC, Message-ID is an originator field, and MUST be
>> present and MUST be unique.
> 
> Do you have a reference for this? I thought this was correct, but I
> recently looked it up in RFC 5322 and predecessors (see
> ,
> and those RFCs at least say it's optional and SHOULD be present.

Heh. I personally believe that a message sent by a mailing list *must*
have the mailing list as the originator: dkim, id, and whatever else.
And then there *should* be a way to reply "off list". Of course then you
have to preserve the original originator all the way to the beginning, so...

And even if "Message-ID MUST be present and MUST be unique", that
doesn't make the converse true: that two copies of the same message
*must* carry the same Message-ID.

-- 
Dimitri Maziuk
Programmer/sysadmin
BioMagResBank, UW-Madison -- http://www.bmrb.wisc.edu



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Re: [Mailman-Users] Message-ID required - was: Reply-to options not working

[Mark Sapiro]

On 02/05/2018 12:22 AM, Stephen J. Turnbull wrote:
> 
> According to RFC, Message-ID is an originator field, and MUST be
> present and MUST be unique.

Do you have a reference for this? I thought this was correct, but I
recently looked it up in RFC 5322 and predecessors (see
,
and those RFCs at least say it's optional and SHOULD be present.

-- 
Mark Sapiro The highway is for gamblers,
San Francisco Bay Area, Californiabetter use your sense - B. Dylan
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