severity 500965 normal thanks For a lot of years this has not been a big problem, but now Yahoo and others are using a policy called DMARC (built on top of DKIM and SPF) and at least Yahoo is actually rejecting messages failing these kind of digital signatures.
The following text comes from DMARC FAQ: (see http://dmarc.org/faq.html#s_3) I operate a mailing list and I want to interoperate with DMARC, what should I do? 1. Operate strictly as a "forwarder," where the RFC5321.RcptTo field is changed to send the message to list members, but the RFC5322 message headers and body are not altered. Pros: Receiving systems can validate the DKIM signature of the message author, if one was present. Cons: Senders that depend solely on SPF for authentication will still fail. Precludes many customary features of mailing lists, such as "Subject:" tags, list footers/disclaimers, etc. (There are other solutions, but I don't think you will want to append ".INVALID" to every yahoo.com address in a From: line). Debian lists have always kept the Subject unmodified, so this is not a problem for us. The main problem is that we add footers to every message. Example: To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/etc Messages already have RFC-2369 conformant headers for the unsubscribe information, namely: List-Unsubscribe: <mailto:debian-devel-requ...@lists.debian.org?subject=unsubscribe> For the "Trouble?" part we already have the "List-Help:" header. What's left? The Archive information. As this is a single line, this could be modified to be a header as well: X-Debian-Archive: https://lists.debian.org/etc To summarize: While it could be fancy and "nice" to have such information in the body, and many mailing lists often do this, by doing so we are breaking interoperability with other email systems. I propose that we stop doing that by not using footers in our lists. The other solution is to change the From: address in the body (which is called "RFC5322.From" header in current documentation) but that would break direct replies. Maybe this would be needed for lists like debian-devel-changes, where the email is actually originated at ftp-master: From: Somebody <somebody at example.com> Thanks. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
