Nick Leverton wrote:
I'm not sure which part of RFC 2821 you're referring to when you talk
about "breaking SMTP" in the context of rDNS checking.
4.1.4
"An SMTP server may verify that the domain name parameter in the EHLO
command actually corresponds to the IP address of the client. However,
the server must not refuse to accept a message for this reason if the
verification fails: the information about verification failure is for
logging and tracing only."
Note the "MUST NOT refuse" if the sender IP check fails. It recognizes
that many hosts are multi-homed (and these days, behind NAT) and there
is no reason to expect/require a correspondence between a DNS name and
the sending IP.
It does make sense to require a resolvable From: address, though.
--
Les Mikesell
[EMAIL PROTECTED]
