>I think I remember a rule that says that delivery to a domain's >A record SHOULD NOT happen, if an MX exists. > >Does that kind of rule really exists ? Or do I mis-remember ?
You misremember. It's MUST NOT. Unfortunately, as others have noted there is still mail software written by people who did not read the spec. The relevant part of the spec is section 5.1 in RFC 5321, which is also in RFC 2821. If one or more MX RRs are found for a given name, SMTP systems MUST NOT utilize any address RRs associated with that name unless they are located using the MX RRs; the "implicit MX" rule above applies only if there are no MX records present. If MX records are present, but none of them are usable, this situation MUST be reported as an error. R's, John _______________________________________________ mailop mailing list [email protected] http://chilli.nosignal.org/mailman/listinfo/mailop
