Richard Frovarp wrote:
I've heard Exchange and Notes/Domino in the past. I don't know if there is any truth to this or not.
I swear Domino did/does it so that they can claim faster queue clearing times.
In any case, be aware that caching of your involved MX and A records can have drastic effects on where a server will attempt to deliver your mail. If for any reason it has a cached A record for one of your lower pref MXes, but none for your higher pref MXes, many will just attempt to deliver to the lower pref MX rather than doing additional queries for your higher pref MXes' A records. You see this happen more often when the name server that is authoritative for the domain's MX record isn't also authoritative for the A records listed in that MX record.
Daryl
