On Tue, 05 Jul 2005 21:27:23 PDT, Justin Mason said:
BTW, someone (possibly Randal L. Schwartz) came up with a neat related trick to the above -- set up an interface alias on *the same machine* as the primary MX, list that as the last MX in the list, and (assuming that the software side of the primary MX is reliable) you're then assured that any SMTP traffic that arrives on that IP's port 25 is spam, since when the primary MX's hardware goes down, this MX will, too.
(Damn, left out a paragraph somehow) And in fact, given that most link hiccups *are* transitory, the chances are *good* that if our attempts at the first MX fail, the link will be back before we finish running through the MX's - at which point we find ourselves talking to a spamtrap.