Yahoo is making my sysadmin life difficult again. A week after I tracked down an SPF issue with my mailserver, Yahoo continues to bounce mail from the neighborhood listserver that I manage.
I found this document today which indicates a recent change by Yahoo is the culprit for my listserver troubles. I love this particular part:
If you are a mailing list owner, what should you do?
Mailing lists are a special case of sending mail on behalf of individuals. The most common option is to use the mailing list’s address instead of the sender’s on the From: line. This will change the reply behavior. Some mailing lists also choose to act as pure forwarders and resend the mail without breaking DKIM signatures. As of this publication, no common mailing list packages provide straightforward configuration options that produce DMARC compatibility, although Mailman has relevant features starting in 2.1.16.
Translation: “right now, there is no mailserver software that can fix our brokenness. You’re screwed.”
Yahoo helpfully lets me know that I can send email to Yahoo accounts if I just munge my message headers, which as far as I know would violate the email RFCs. There’s also no way I’m going to fuck up the mailing list experience of 325 users just to work around the incompetency of some dipshits at Yahoo.
Hey Yahoo: listservers aren’t going away any time soon. Either fix your shit or get out of the email business.