On 2021-04-29 Colin Stanners wrote:
I'm afraid that if I understand the situation correctly, the MXVerify result is not an non-error, it is a real problem, and the likely cause of your issue.
See the Gilbert reply. This doesn't jive with the understanding of these 2 old hands.
That serverfault link is unrelated, you are not sending emails only, this discussion is about your domain receiving email.
Ya, but its answer re: RFC5321 is correct:
2.3.5. Domain Names Only resolvable, fully-qualified domain names (FQDNs) are permitted when domain names are used in SMTP. In other words, names that can be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed in Section 5) are permitted, as are CNAME RRs whose targets can be resolved, in turn, to MX or address RRs. ===
So per RFC is the receiving domain can either resolve to MX, *or* direct A RR (as my domain did).
Further:
5.1. Locating the Target Host If an empty list of MXs is returned, the address is treated as if it was associated with an implicit MX RR, with a preference of 0, pointing to that host. ===
As far as I can tell, 5321 is still in force and not superseded.
I had a valid, empty (non-existent) MX record set. That should be valid.
If you have a different understanding, feel free to RFC-enlighten us!