@ IN SOA ns.isp.net. netmaster.isp.net. ( 1998100100 86400 3600 604800 345600 ) s/netmaster/hostmaster/ see RFC 2142 or, i think it was piet who recommended being conservative, and do not relying on aliases, rather use a real mailbox name. So that person can safely go on a two-week holiday? I'd rather put in a real hostname and not rely on MX records
not discussing MX RRs. mailbox names. the reason i mention piet's recommendation is twofold, i think he used to chair this group, and he wrote one of those silly rfc things. though checking 1537, this point seems not to have made the final cut. piet, you still around?
(Remember that sendmail falls back to A records if it can't find any MX records for a host.)
i think of it the other way, but with the same result. mail will be sent to the (address in rdata of the) A RR unless some one put in an MX RR because the (interface denoted in the) A RR can not accept mail. randy