Quoting Craig Sanders (cas@taz.net.au):
actually, no. it would not Be Extremely Dumb. Having multiple PTR records for an IP address is a valid and occasionally useful DNS configuration.
Please do describe examples for an MTA host.
for various fairly obvious reasons
which don't strike me as being particularly obvious.
You'll just have to work that out, then.
-- and, more to the immediate point, would completely and automatically bollix any aim to resolve to any specific hostname to make some hypothetical MTA happy.
it's *entirely* the MTA's fault if it freaks out over perfectly valid DNS configuration.
Funny thing about system administration. When the object is to deliver mail, saying some problem is a remote MTA's 'fault' doesn't actually induce delivery.
configuring an MTA to require matching rDNS resolution is Extremely Dumb in most situations
Agreed. But not relevant.