Hello, > 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 ?
https://tools.ietf.org/html/rfc5321#section-5.1 5.1. Locating the Target Host can be read that MX records have preference, but it explizitly avoids mentioning "A or AAAA" records if no MX is found. The sentence: [...] 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. [...] implies a A/AAAA DNS query, but does not explicitly state so. I had a case where lb1-smtp-cloud3.xs4all.net delivered to an A record where an MX existed. -- [email protected] +49 171 3101372 5 years to go ! _______________________________________________ mailop mailing list [email protected] http://chilli.nosignal.org/mailman/listinfo/mailop
