On 14/10/2026 15.44, Dan Mahoney wrote: > On Oct 14, 2026, at 5:26 AM, Otto J. Makela <[email protected]> wrote: >> I'm certain you know your stuff re SPF, but apparently I don't. >> >> Can you please expand a bit about SPF failures, since AFAIK on a >> properly configured mailing list the SMTP "mail from" (aka envelope >> sender) of messages sent through it would be to mailing list server, >> and naturally you'd include that in your domain's SPF? > > Naturally?
This is, as far as I have understood, the way a mailing list server is supposed to function with SPF (RFC 7208)? > My day job is JTD.org (rot1), and lots of us participate in open source > mailing lists. (We also run a bunch) I'm not going to include > mailop.org, nanog.org, and ietf.org in our SPF records, nor should I > magically know what lists my users may or may not participate in. […] Why would this be needed? SPF only concerns the SMTP dialogue (envelope sender / HELO), like DKIM only concerns the actual message. Thus, the way the mailing list should function is to keep the message headers/body as intact as possible, and rewrite the envelope sender to itself, which prevents any bounces from mailing list member addresses from bothering the person sending a message to the list. [There of course are somewhat pathological cases where you just can't keep all the DKIM-signed headers intact (I was able to convince certain domains to stop signing headers like List-Id, but I did have to threaten to unsubscribe all their users from our #work mailing lists), and in these cases the "From" rewriting you describe does come into play] -- /* * * Otto J. Makela <[email protected]> * * * * * * * * * */ /* Phone: +358 40 765 5772, ICBM: N 60 10' E 24 55' */ /* Mail: Mechelininkatu 26 B 27, FI-00100 Helsinki */ /* * * Computers Rule 01001111 01001011 * * * * * * */ _______________________________________________ mailop mailing list -- [email protected] To unsubscribe send an email to [email protected]
