March 6, 2016
11:37 a.m.
On Mar 05, 2016, at 04:14 PM, Mark Sapiro wrote:
The issue is that there is an MX record for mailman3.org pointing to mail.mailman3.org, but mail.mailman3.org doesn't have an A record; it has a CNAME pointing to mailman.iad1.psf.io which is the canonical name of the server.
RFC 2181, sec 10.3 says the target of and MX must have address records, not CNAME. I.e. mail.mailman3.org should not have a CNAME, but rather an A record pointing to 104.239.228.201 or I suppose instead, the MX for mailman3.org could point directly at mailman.iad1.psf.io.
Fixed by setting mail. to an A record. Give it time to propagate, and it has a 3h TTL.
Cheers, -Barry