On Sun, Aug 31, 2003 at 02:09:34AM +0200, Brad Knowles wrote
If it's behind a NAT, how would it know the external DNS name?
If that IP address on the NAT device is dynamically assigned and the
machine is not an intelligent host running software capable of
updating a dynamic DNS record (as 99.999% of all NAT/router devices
are almost certainly going to be), then how would the internal host
know what this external DNS name is?
That point is moot... because if you're sending direct to the remote
MX from a dynamic IP address, there'll be a helluva lot more machines
rejecting you for being on a dynamic address than those worrying about
a syntactically correct HELO. IOW, your mail is a lot more likely to
be accepted with an incorrect HELO from a static IP address.
One could argue that if they don't understand DNS, they shouldn't
run a mail server.
I would like to be able to make such an argument. I really
would. Indeed, I could even see making such an argument part of a
BCP, but only if the recommended practice did *NOT* involve rejecting
the connection outright just because they did not have reverse DNS
properly configured.
How about total lack of rDNS ? I block on that, not on mismatching
rDNS.
--
Walter Dnes <waltdnes(_at_)waltdnes(_dot_)org>
Email users are divided into two classes;
1) Those who have effective spam-blocking
2) Those who wish they did
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