SMTP NDR

[Mike Mullins]

Your message did not reach some or all of the intended recipients.

Subject: Server Performance Report - SERVER
Sent: 3/16/2005 6:00 AM

The following recipient(s) could not be reached:

mull...@netdirect.net on 3/16/2005 6:01 AM
The e-mail address could not be found. Perhaps the recipient moved to a
different e-mail organization, or there was a mistake in the address. Check
the address and try again.
<SERVER.KDC.local #5.1.8 smtp;501 5.1.8 Sender domain must exist>

[Grady W Smithey III]

The "Sender domain must exist" part of the error code indicates that the
server you were trying to send to attempted a reverse lookup on yours, and
couldn't find a PTR record for it. You'll want to take a look at the section
on creating a Reverse Lookup Zone in the following article:

HOW TO: Create a New Zone on a DNS Server in Windows Server 2003
http://support.microsoft.com/default.aspx?scid=323445

"Mike Mullins" <Michael...@commdatanetworks.net> wrote in message
news:eRtpxxnK...@TK2MSFTNGP10.phx.gbl...

[Mike Mullins]

The PTR records is in there
"Grady W Smithey III" <off...@islagiatt.org?subject=Regarding%20Your%20Post>
wrote in message news:eaM8O6nK...@TK2MSFTNGP09.phx.gbl...

[Kent]

I don't think it's trying to do a reverse lookup so it wouldn't be the PTR
record. It's probably just trying to do a normal "forward" lookup on the
domain part of the sender's email address. Make sure the sender's email
address is correct (i.e. not yourdomain.local) and make sure the nameserver
for the domain is accessible from the Internet and responding to DNS
requests.

Kent

[Grady W Smithey III]

If it was doing a lookup on the recipient's address, why would the error
state that the sender domain doesn't exist?

"Kent" <Ke...@discussions.microsoft.com> wrote in message
news:6150B64D-51E0-446D...@microsoft.com...

[Kent]

I never said it was doing a lookup on the recipient's address. I said it's
doing a forward lookup on the sender's address. A forward DNS lookup turns a
name (yourdomain.com) into a number (192.168.0.1). A reverse DNS lookup turns
a number (192.168.0.1) into a name (yourdomain.com).

When the recipient's mail server does a DNS lookup of the sender's domain,
it only does this to check the validity of the incoming message. It's not
required to deliver the message but it helps reduce spam. That's why some
mail servers require it and other's don't. Some people call this a "reverse
lookup" but it's not the same as a "reverse DNS lookup". Since it's doing the
lookup on a domain and not on an IP address, it's a *forward* DNS lookup
which has nothing to do with PTR records.

[Grady W Smithey III]

Sorry for the misunderstanding - I hadn't had my usual daily dose of
caffiene yesterday when I read your message, so I didn't parse it correctly.

"Kent" <Ke...@discussions.microsoft.com> wrote in message

news:68F155A5-1E01-4D5E...@microsoft.com...