Re: [ietf-smtp] Email explained from first principles

[John R Levine <[e-mail]>]

On Thu, 27 May 2021, Kaspar Etter wrote:

> This conversation went off on a tangent, but I also want to comment on a couple of things:
>
>> On 24 May 2021, at 16:03, John Levine <[e-mail]> wrote:
>>
>> It appears that Kaspar Etter  <[e-mail]> said:
>>> 2. List-Name header field: Mailing lists shouldn’t rewrite the messages of others and break DKIM signatures in the process.
>>
>> Sorry, but this shows some serious misunderstandings about both DKIM and mailing lists.
>>
>> DKIM is a transport signature, which in this case shows that the message was sent from the author
>> to the mailing list system.  List apply their own DKIM signature on the mail they send.
>> Mailing lists have been editing messages for 40 years, long before anyone
>> ever thought of DKIM or DMARC.   It is a well known DMARC failure that it doesn't work with mailing lists.
>> Some people have tried to rewrite history and claim that it is the lists' fault but they are wrong.
>>
>> The whole point of ARC is to provide recipient systems with info to help recognize when they should
>> ignore DMARC and deliver mail from lists and other legitimate senders that don't happen to match the
>> assumptions that DMARC makes.
>
> I disagree.

You're welcome to your opinion, but you don't get to rewrite 40 years of 
history.  We've spent a decade with people insisting that the entire 
e-mail world has to change the way it works to conform to the lastest 
FUSSP.  We saw it with SPF, we're seeing it with DMARC.  It didn't hapen 
with SPF, and it's not happening with DMARC.  For example, mailing lists 
have been editing messages for a long time, they have good reasons to do 
so, and they're not going to stop.

I'm not guessing about the reasons for ARC, I know the people who 
developed it and I believe I am correctly describing the reason they 
invented it.  It includes some of the largest mail providers in the world. 
They all use DMARC, and they understand that DMARC's limitations cause a 
lot of gratuitous pain for their users who've been using mailing lists for 
a long time.  It's not a large fraction of the total amount of mail, but 
it's a large fraction of the mail they care about.

Regards,
John Levine, [e-mail], Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly