>Its not "round robin", the RFC is quite explicit about this: > 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.
The mosts MTA's, still, will use the physical order of the MX records as they arrive in the DNS answer packet, take the first MX hostname, and then take the first physical A record for that hostname. It's the DNS (BIND at least) that varies the order on the physical record sequence. By default, BIND is ordering is "cyclic". Len ____________________________________________________________________ www.menandmice.com/DNS-training : DNS Training BIND8NT.MEIway.com: Secure config ; DNS and mail interactions IMGate.MEIway.com : Free, proven config for anti-mail-abuse gateways To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
