• From: "John T \(Lists\)" <johnlist@xxxxxxxxxxxxxxxxxxx>
  • To: "'[ExchangeList]'" <exchangelist@xxxxxxxxxxxxx>
  • Date: Wed, 18 Jan 2006 09:54:35 -0800

You are looking at the wrong side.


Since there is no A record, there is no way to see if there is a PTR record
for the corresponding IP address.


John T

eServices For You


-----Original Message-----
From: ChongJa@xxxxxxxxxxxxxxxx [mailto:ChongJa@xxxxxxxxxxxxxxxx] 
Sent: Wednesday, January 18, 2006 9:14 AM
To: [ExchangeList]
Subject: [exchangelist] NDR

I have a user that's getting an NDR when sending to a user
Although the NDR appears that it's doing some sort of reverse DNS lookup, I
don't think this is the case. When I put in in
it comes back with an error that their mx record is referencing a cname
rather than an A record. I did some research which suggests that when this
is any mail sent to this domain is rejected. When I connect to their mail
server on port 25 and issue a helo it comes back with syntax error. When I
issue ehlo it does not appear to do anything. Wondering if this is something
on their end or ours. (All our outbound mail goes out to mailsweeper
smarthosts (2)


Received:571 - MAIL REFUSED - Reverse DNS failed; cannot resolve the
( domain in the HELO command.


James Chong

ETS Sr. Exchange Engineer

Office: 703.206.7548

Cell: 703.863.1483



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