on fri sep NUMBER NUMBER at NUMBER NUMBER NUMBERpm NUMBER vernon wrote as i understand it dns a records are used in a rotating fashion for load balancing but dns mx records are used in order or prority meaning the NUMBER before the NUMBER and only NUMBER if the NUMBER isn t available that s the theory yes but only some of the mail is actually being scanned which leads me to believe that not all of the mail is actually hitting that box and the NUMBER never goes down why have i got something confused here no but either due to some technical glitch or downright just wanting to do so people send to the secondary it s a semi usual spammer trick actually to bypass the main server and send directly to a secondary since it will either have less filtering or be trusted or mx records in the mail world are all explained in rfc NUMBER section NUMBER multiple mx records contain a preference indication that must be used in sorting see below lower numbers are more preferred than higher ones if there are multiple destinations with the same preference and there is no clear reason to favor one e g by recognition of an easily reached address then the sender smtp must randomize them to spread the load across multiple mail exchangers for a specific organization if it determines that it should relay the message without rewriting the address it must sort the mx records to determine candidates for delivery the records are first ordered by preference with the lowest numbered records being most preferred the relay host must then inspect the list for any of the names or addresses by which it might be known in mail transactions if a matching record is found all records at that preference level and higher numbered ones must be discarded from consideration if there are no records left at that point it is an error condition and the message must be returned as undeliverable if records do remain they should be tried best preference first as described above randomly generated tagline now let s say i like sheep and now let s say i take the sheep to a christmas party bob golub 