Hello, On Tue, 8 Dec 2020, Per Jessen wrote:
> > AFAICT, mailman offers only two (marginally useful) options, > > per list - replace from with list address or wrap message in > > an outer message. Neither is of much use to us, we don't want > > the From: address to change. > > you realize, though, that it's impossible to keep "From:" as-is > if you want to deliver postings reliably to all recipients?
Well, for at least the last four years, it has not caused us any problems. (i.e. I haven't seen any tickets nor have I heard anyone complain).
That's not a real argument because MTA admins just began to implement SPF/DKIM/DMARC during the last two years.
Hmm, I'm not to sure about that estimate. Looking at e.g. our internal SPF whitelist, the earliest entries are eight years old.
Again:
This issue is not caused by SPF alone. IIRC classic SPF checks only covered envelope sender.
It's caused by DMARC which mandates checking the From: header. And DMARC adoption is increasingly used for being able to deliver to big players like GMail, Yahoo and Microsoft.
Right, and as DMARC checks the From: header, neither it, nor any of the other signed headers or the body must be changed by the list server, that usually includes Subject.
the DMARC policy for suse.com was only recently updated to include "subject", but I presume some bigger providers have already been quarantining mails from suse.com addresses since mid-November.
Fwiw, the only one that actually notifies the sending mta is gmail - I see nothing from Microsoft nor Yahoo.
Sure, I merely wanted to refute the claim that From: munging is a necessity of mailing list servers for DMARC reasons (still quoted above).
If the list server then doesn't change any of those headers no From: rewriting is necessary, unlike you claimed above. It is merely the alternative to other header-rewriting (or body-rewriting even); if the list server does any of that, then yes, From munging is necessary.
Currently, all we do is add a footer.
That's body rewriting and would also invalidate DKIM signatures (if body is included, of course, but it often is), and hence necessitate From munging. Ciao, Michael.