On 8/31/07, Joe Abley
[A] --------- [B] \ / X / X / \ / [C]
[A], [B] and [C] are different networks on the Internet. I have a priority-0 MX installed at [A], and another one at [B]. The MX at [A] has a lower number in its RDATA than the one at [B] (i.e. the one at [B] is the backup).
Suppose some device at [C] tries to send me mail, and at the time it chooses to attempt delivery, there's a network problem which prevents traffic from getting through. It instead delivers to the backup MX at [B]. There is no network problem between [B] and [A], so mail is forwarded on straight away.
I'm just curious what reasons, and they may be myriad, explain why SMTP will route around the damage using the MX priority, but TCP/IP won't? Ie, I can send mail where I can't send a packet?
Joe
Hamish. -- http://del.icio.us/Hamish.MacEwan http://urltea.com/3jm?GoogleSharedItems