--On Friday, September 22, 2006 8:37 -0700 John Rudd <[EMAIL PROTECTED]> wrote:
* A PTR record for its IP address ("the connecting IP address"). Failure
leads to a temporary rejection of the message.
* The PTR record must resolve to a name which is they key for an A
record. Failure leads to a temporary rejection of the message.
* The A record must have at least 1 IP address which matches the
connecting IP address. Failure leads to a permanent failure of the
message.
* The name from the PTR record must not look dynamic. Failure is a
permanent rejection of the message.
* The above restrictions can be avoided via SMTP-AUTH.
I have yet to find out that any such rejection was a valid email message.
I happen to be logging all missing RDNS, accepted or not. Within 30
minutes we saw the following on one host of five. The first 3 have no PTR.
The other 2 have nonmatching forward and reverse.
IP domain in the sender address (my comment)
192.165.223.234 reuters.com (news)
64.30.239.160 mailer-relay.sportsline.com (sports news)
206.220.211.195 indiaclub.com (online vendor)
57.66.153.130 weforum.org (nonprofit org)
64.39.15.8 lists.kabissa.org (nonprofit org)
Joseph Brennan
Columbia University Information Technology
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