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If there are no MX records for a domain the mail should be delivered to the A-record. If there are MX records for the domain, but mail delivery to it fails, it

by kawsper 13y ago

If there are no MX records for a domain the mail should be delivered to the A-record. If there are MX records for the domain, but mail delivery to it fails, it should not try to deliver to the A-record. http://tools.ietf.org/html/rfc2821#section-5 http://tools.ietf.org/html/rfc2821#section-5