> On Oct 14, 2026, at 5:26 AM, Otto J. Makela <[email protected]> wrote: > > On 12/10/2026 19.15, Al Iverson via mailop wrote: >> Keep reaching for that brass ring, but making this list "forwarding >> fail proof" isn't possible based on how the world works today. If you >> modify the MLM to stop making changes to prevent DKIM failures you're >> still going to have problems with SPF failures. Given that Microsoft >> and Google require both SPF and DKIM pass for bulk senders, that just >> shifts the pain, it doesn't eliminate it. > > 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? My day job is JTD.org <http://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 <http://mailop.org/>, nanog.org <http://nanog.org/>, and ietf.org <http://ietf.org/> in our SPF records, nor should I magically know what lists my users may or may not participate in. What we do include in our SPF records is things like our salesforce setup, which is specifically, contractually, allowed to send mail on our behalf. Other than this, we would expect that either the mailing list either would rewrite messages such that the From: address is the list address itself, and perhaps add a reply-to of the original sender -- or that it will not interfere with the headers at all (such as in the case of a simple alias-list, so DKIM survives -- no mody mods, and no mods of the standard list of headers. With DMARC, either of DKIM or SPF typically has to pass, not both. Some mailing lists have knobs to look at the p= value of the sending domain, and only do the rewriting if the domain has p=reject or p=quarantine, but honestly, consistent behavior is the better option. -Dan _______________________________________________ mailop mailing list -- [email protected] To unsubscribe send an email to [email protected]
