[bitfolk] Re: moving on from ancient self-hosted mailman

Hi Adam, On Sun, May 28, 2023 at 05:53:11PM +0100, Adam Spiers via BitFolk Users wrote: It's worth looking in to this as SPF normally isn't a problem for mailing lists, neither in Mailman 2.x nor 3.x or most other implementations. The reason why it's not a problem is that SPF works on the envelope sender, not the From: address, and all versions of Mailman normally replace the envelope sender with themselves (which may or may not include VERP encoding to catch individual bounces). For example, your post (for me) has the envelope sender <users-bounces+andy=bitfolk.com(a)mailman.bitfolk.com> so when my infrastructure does an SPF check it will be against the SPF record at mailman.bitfolk.com. In the case of this mailing list we've ALSO replaced the From: address with the list's address but even if we hadn't, the SPF check is still against the envelope sender so at no point will it check the SPF of gmail.com. Us changing the From: address was a defence against DKIM, which you may be confusing with SPF here. DKIM does work on the From: address. If you keep the poster's From: address and the poster has included a DKIM signature, AND your Mailman has modified the mail in any way, the DKIM signature will be invalidated. Most users of mailing lists appreciate the posts being modified, perhaps to include an explanatory footer, and/or a prefix on the subject line. That changes the content which in turn breaks the DKIM signature. The RFC for DKIM says that invalid signatures should be treated like no signature at all, i.e. should not be penalised, but plenty of receiving sites do penalise a failing DKIM signature. Both Mailman 2 and Mailman 3 have options to replace the From: address with the list's address. Despairing at how remote sites treat DKIM, that's what we did, and it's what a lot of other mailing lists I know of have done too. It makes it harder to see the original real email address, but it prevents DKIM failures and means you can also DKIM sign the mails yourself. I didn't find the DKIM thing to be the main reason to move away from Mailman 2. The main reason was that MM2 is a Python 2-only app that is now EOL upstream and is therefore not shipped by any Linux distribution that has also stopped shipping Python 2, which is most of them. It's a shame because MM3 is a behemoth. I feel it's overly complex. A straight port of MM2 to Python 3 would have been much more welcome. Failing that I wish I could have just put email mailing lists into the dumpster of time. I don't have any experience with those, but they all seem okay. I would not expect your issues with getting email in to Gmail and Yahoo! to go away. Replacing your From: address with that of the list might help you a bit. Personally I'd be tempted to switch to Discourse, which has an email participation mode if desired, and has SaaS options if you didn't want to self-host. It's what I'd have replaced BitFolk's mailing lists with if there weren't so much pushback from people who are wedded to the 20th century mailing list experience. (Not to be confused with Discord, which is a closed source chat application that does have some announcement features.) Cheers, Andy -- https://bitfolk.com/ -- No-nonsense VPS hosting