[Mimedefang] Slightly OT: Advice on updating MX record (was SMTP error return after DATA?)

[Tony L. Cratz]

	If you are not in a real hurry for this change to happen, a
common
	method is to lower your time values to a small value (on less
then
	an hour) wait the up to your current expire time (for example if
	your expire time is 1W then you would wait for a week). Once the
	old expire time value has been reached then you can change the
	MX to point to the new IP and have the rest of the internet up
to
	date after the new expire time has been reached (say 15M).


	
Tony

-----Original Message-----

I can easily control who can connect via an access map.  BUT, I'm
concerned
about the amount of time it will take for my DNS change to propagate out
to
the rest of the net.  I've read that most see changes in 12-24 hours, a
good
bit in 48 hours, and some may take as long as 72+.  If I just switch my
MX
in one fell swoop then sites that haven't received the update will still
be
trying to relay mail to my old MX record and their connections will be
rejected.  If it takes them a while to get the updated DNS information
they
may start bouncing mail destined for my domain.