Incoming SMTP in the year 2017 and absence of DKIM

John Levine johnl at
Fri Dec 1 01:47:47 CST 2017

In article <3d84c686-aa5f-8180-8a37-be77fef949a8 at> you write:
>I would also configure MLMs to forward unknown bounces to the -owner. 
>Hopefully the -owner would then feed (a sanitized copy of) the unknown 
>bounce type the MLM maintainer(s) to improve said MLM.

I suppose that would make sense for the 0.1% of mailing lists run by
people with the skill and interest to hack on their list software.

>> It's a rathole, it doesn't scale, and it is not a bug that you can 
>> send mail to people who you don't already know.
>I wasn't aware that DKIM-ATPS necessitated needing to know who you were 
>going to send to.

ATPS was an experiment that failed.  Nobody uses it, it didn't scale.

>> If identities were a magic bullet, we'd all be signing with S/MIME.
>I am (and have been for years) a proponent of S/MIME.

I can't help but note the absence of S/MIME signatures on roughly 100%
of all of the messages in this thread.

>(I think we're still talking about how can an intermediate mail server 
>be authorized to be part of the SMTP end-to-end mail delivery chain. 
>Even if said intermediate mail server is downstream of the sender.)

Yeah, that's what ARC is intended to do.


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