Peter Shute writes: > I don't know if we are doing SPF/DKIM ( or what they are).
You should ask the people responsible for your mailserver. SPF and DKIM in themselves are good things because they prevent rejections of mail that you send directly to another domain that implements them, and because it's evidence to reasonable people that you follow best practice. If you/they are not doing it, you/they should. How they work: SPF and DKIM are separate protocols that provide a certain degree of authentication for the *hosts* that transmit mail claiming to originate in a domain. The protocols work (more or less) by publishing a list of IP addresses that are allowed to send mail from the domain. Since it's information attached to a domain, you get that list from the domain's name server. There's a bit of crypto technology involved so that receivers can trust the information. The problem is that the only IP address that you can trust at all is the direction connection from the host you receive the message from. In other words, although Internet mail is designed as a "store and forward" system where messages are passed from host to host until they reach their destination (where they user's mailbox is), effectively these protocols allow only one hop, or authentication fails. In the case of DMARC (a "super" protocol that specifies how to use this information), a domain is allowed to *demand* that you reject the mail if authentication fails. That means that mailing lists (which necessarily involve at least two hops in most cases of interest) *always* fail authentication at *every* destination conforming to DMARC. Yahoo! is lighting up a cigar in an elevator filled with pregnant women. :-( Fortunately, I suspect that they are about to bring down the wrath of Olympus upon themselves as their users start losing mail and being refused service on mailing lists, etc. This is a snafu on the order of Microsoft's backward compatibility break with Office '97 or so. Regards, Steve ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org https://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: https://mail.python.org/mailman/options/mailman-users/archive%40jab.org