Certain email recipients cannot be reached

[quolo]

Hi gang,

I'm at a loss with this problem. I'm running a Win 2K server with Exchange 2000 for about 10 users, which was only set up a few months ago. For the most part, everything works fine.

Most of our outgoing email works fine, except for a few recipients that seem to usually cause problems. After a few days of trying to deliver an email, this is the error message I get:

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

Subject: Forgot to attach the minutes. Here they are.
Sent: 3/26/2003 4:30 PM

The following recipient(s) could not be reached:

bibi@xxx.com on 3/28/2003 4:32 PM
Could not deliver the message in the time limit specified. Please retry or contact your administrator.
<CSMAIL.velocity.local #4.4.7>

I have a couple frequent recipients at xxx.com that usually cause problems, as well as a couple others from different domains. It doesn't matter who sends the emails, as I've seen several users have errors to the same recipients. Could this be a DNS issue of some kind? Firewall? Boogeyman?

I'll attach the message header at the bottom of this post in case that's any help. Thanks in advance.

Microsoft Mail Internet Headers Version 2.0
From: postmaster@OurCompany.com
To: me@OurCompany.com
Date: Fri, 28 Mar 2003 16:31:38 -0500
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
boundary=&quot;9B095B5ADSN=_01C2EA87B4A599120000068CCSMAIL.velocity.&quot;
Message-ID: <RUJRwFcN500000025@CSMAIL.velocity.local>
Subject: Delivery Status Notification (Failure)

--9B095B5ADSN=_01C2EA87B4A599120000068CCSMAIL.velocity.
Content-Type: text/plain; charset=unicode-1-1-utf-7

--9B095B5ADSN=_01C2EA87B4A599120000068CCSMAIL.velocity.
Content-Type: message/delivery-status

--9B095B5ADSN=_01C2EA87B4A599120000068CCSMAIL.velocity.
Content-Type: message/rfc822

content-class: urn:content-classes:message
Subject: Forgot to attach the minutes. Here they are.
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary=&quot;----_=_NextPart_001_01C2F3DE.DADF5E5A&quot;
Date: Wed, 26 Mar 2003 16:30:00 -0500
Message-ID: <89697DF11E574F43A0005F2D1BCF943B9CD5@CSMAIL.velocity.local>
X-MimeOLE: Produced By Microsoft Exchange V6.0.4417.0
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
Thread-Topic: Forgot to attach the minutes. Here they are.
Thread-Index: AcLz3tnf9nP+dGJaTO6Q+8oB31XzjQ==
From: &quot;MyName&quot; <me@OurCompany.com>
To: BunchOfPeople'sEmails

------_=_NextPart_001_01C2F3DE.DADF5E5A
Content-Type: text/plain;
charset=&quot;us-ascii&quot;
Content-Transfer-Encoding: quoted-printable

------_=_NextPart_001_01C2F3DE.DADF5E5A
Content-Type: application/msword;
name=&quot;CAB Minutes (3-19-03).doc&quot;
Content-Transfer-Encoding: base64
Content-Description: CAB Minutes (3-19-03).doc
Content-Disposition: attachment;
filename=&quot;CAB Minutes (3-19-03).doc&quot;


------_=_NextPart_001_01C2F3DE.DADF5E5A--

--9B095B5ADSN=_01C2EA87B4A599120000068CCSMAIL.velocity.--

 

[ama299]

I have had this problem before. You can try and search for the record in your dns and delete it, and if you us a forwarder for your dns you can try using a different outside DNS server.

 

[quolo]

In my domain's DNS, the reverse lookups were a bit weird, so I changed them to match the forward. Still waiting a couple days for that to propagate, and will keep you posted.

The theory is that some recipients may be checking the reverse lookup zone as an anti-spam measure. Will keep you posted.

 

[quolo]

Interestingly enough, this is still a problem.

A while ago, I went to my ISP's DNS adminstration utility and changed the Reverse Lookups for my mail IP to read:

&quot;mail.mycompany.com.&quot;

I'm at a loss. bibi@hercompany.com still doesn't go through. Any suggestions? I'll try anything that doesn't involve a goat or a paper shredder.

 

[EdwinSKH]

I would try to do a basic communication test by telnetting to their mail server and send a test message to the recipient as outlined in the following article. Get the other party to try it also if necessary. The error message may give you a better idea what is wrong.

http://support.microsoft.com/default.aspx?scid=kb;en-us;153119

 

[quolo]

Thanks for this resource. Here is what I have done and the results I received:

I opened a cmd prompt and typed:

220 hercules.amhosting.com ESMTP
telnet bibiscompany.com 25
HELO test.bibiscompany.com
250 hercules.amhosting.com
mail from:<me@mycompany.com>
250 ok
rcpt to:<bibi@bibiscompany.com>
553 sorry, that domain isn't in my list of allowed rcpthosts <#5.7.1>

There you have it. How do I interpret this information? I verified that I spelled the recipient email correctly.

 

[EdwinSKH]

Offhand, I would say it is a DNS config error on the Recipient's ISP, Or your own ISP. Your domain could also be blocked by the recipient mail server. This article may help.

http://support.microsoft.com/default.aspx?scid=kb;en-us;153001

 

[quolo]

Man...for a second, I thought that CNAME thing had to be the problem. I got all excited.

I verified with my ISP and by my own eyes that there is no CNAME alias in our DNS entry.

Our ISP DNS info reads:

Host Record Type Points to
A xxx.xxx.xxx.xxx
mail A xxx.xxx.xxx.yyy
www A xxx.xxx.xxx.xxx
MX 10 mail.ourcompany.com

xxx.xxx.xxx.xxx above is our static IP used for our website
xxx.xxx.xxx.yyy above is another static IP used for mail
Both are hosted on the same in house Win2K server.
Reverse DNS entries for both xxx.xxx.xxx.xxx and
xxx.xxx.xxx.yyy point to mail.ourcompany.com

I did a check to see if we were being blocked on a spam list and we weren't listed.

What other factors might cause a recipient mail server to block our emails?

 

[j3w3ll]

i have had this problem aswell. i only had 1 domain that i could not send to

what i did to solve it was to make my Exchange 2000 server send via a smarthost instead of straight out to the net.

properties of smtp virtual server, delivery, advanced.

FQD the name of your server ie server1.msn.com
smarthost ie - mail(smtp).microsoft.com (or what ever your isp is).

Give it 5 minutes then try and send, i wish you good luck i know how annoying this is, i can only say this worked for me, good luck..

Ryan

 

[quolo]

Thanks for the idea. I gave it a look and I think I've already got it configured that way.

Currently, my FQDN for my SMTP Virtual server points to: mail.mycompany.com;
The Smart Host listed is mail.myISP.net;
The &quot;Attempt direct delivery before sending to host&quot; box is unchecked;
And &quot;Perform reverse DNS lookup on incoming messages&quot; is checked.

See any potential problems in that setup?

 

[j3w3ll]

No thats what i've got setup aswell, i know what your going through it is so annoying!!! can you ping the recipients mail server from your Exchange server if not maybe try a LMHOST file to point to it.

 

[jsd2003]

I say turn off ESMTP and just use regular SMTP. See if that clears it up. ESMTP only works when you're sending to another Exchange server anyway. (Hint: Send HELO instead of EHLO)