[Mailman-Users] cause of bounces

Grant Taylor gtaylor at tnetconsulting.net
Fri Oct 20 00:14:42 EDT 2017

On 10/18/2017 11:50 AM, Mark Sapiro wrote:
> This is the crux of our disagreement. The outbound message is still the 
> original author's message, albeit slightly altered by subject prefixing, 
> content filtering and/or other transformations to conform with list 
> policies. I don't agree that it is a completely new message. I think it 
> is still the original message with only technical and formatting changes.

RFC 6377 - DomainKeys Identified Mail (DKIM) and Mailing Lists, 
disagrees with you.  (RFC 6377 is also currently known as BCP 167.)

§ 3.2 calls this out specifically:

> resending:  A resending MLM (see Sections 5.2 and 5.3 of [EMAIL-ARCH]) 
> is one that may make changes to a message.  The output of such an MLM 
> is considered to be a *new message*; 
> *delivery of the original has been completed* prior to distribution of 
> the reposted message.  Such messages 
> are often reformatted, such as with list-specific header fields or other 
> properties, to facilitate discussion among list subscribers.

/The output of a resending MLM is/ *a new message*.

> MLM Output:  *MLM* (sending its reconstructed copy of the originating user's 
> message) *is Author*; MLM's ADMD is Originator and Signer; the ADMD of each 
> subscriber of the list is a Verifier; each subscriber is a Receiver.

*The resending MLM is the author* /of the new message/.

> The dissection of the overall MLM operation into these two distinct phases 
> allows the DKIM-specific issues with respect to MLMs to be isolated and 
> handled in a logical way.  The main issue is that the repackaging and 
> reposting of a message by an MLM is actually the construction of a 
> completely new message, and as such, the MLM is introducing new content 
> into the email ecosystem, consuming the Author's copy of the message, 
> and creating its own.  When considered in this way, the dual role of the 
> MLM and its ADMD becomes clear.

Since we have been talking about modifying more than /just/ the SMTP 
envelope, we are indeed talking about a resending MLM and not an alias MLM.

Grant. . . .
unix || die

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