Can't email a certain domain

[Whitemtntn]

Busy Exchange 5.5 SvcePk4 on NT server:
No other problems with outgoing mail, but when anyone here tries to send an email to this guy@DOMAIN.com (or anyone else there), we get this fairly quick...
"Undeliverable" Your message did not reach some or all of the intended recipients.
Subject: test
Sent: 1/26/2004 3:28 PM
The following recipient(s) could not be reached:
'guy@DOMAIN.com' on 1/26/2004 3:28 PM
The recipient name is not recognized...

I performed a few connectivity tests....

1. Used a dial-up account on a laptop and sent an email to same email address from a hotmail account. This worked.

2. nslookup
>set type=MX
>DOMAIN.com
This worked.

3. telnet DOMIAN.com 25
This worked.

I spoke to the people at DOMAIN.com and they aren't experiencing any problems with their email. I spoke to my ISP and their tests indicate there is no problem connecting to DOMAIN.com's mail server.
We are behind a firewall and have an internal DNS server (we host our own email, website and other things..) This all seems to be in order.

Sooooo.... I am at a loss. Any ideas on the problem, or other tests I can perform? Some kind of logging at Exchange that would indicate the failure? Does perhaps the cache.dns file on our NT 4.0 internal DNS server need updating?

Thanks,
WhiteMtntn

 

[rdroske]

Is reverse lookup on your mail servers IP working correctly? Some domains reject emails if reverse lookup fails.

You can check at

http://remote.12dt.com/rns/

 

[Whitemtntn]

Good suggestion... Yes it is resolving correctly. I actually had verified that with my ISP already.

I tried turning up the logging levels on Exchange to maximum and enabling Message Tracking for the Internet Mail service to see if I could identify where the problem is-- no dice. Exchange is not very good at telling you anything useful with its tracking features.

I think I have pretty much verified that this is some kind of Exchange issue... From the Exchange server I opened up an SMTP Telnet connection with their mail server, and sent them an email. They haven't responded yet, but I didn't get an error.

-Whitemtntn

 

[Whitemtntn]

I am still working on this problem--
Perhaps this might ring a bell to someone...

I have tracked down what I think is the problem...
504 <MLTW_CLUSTER>: Helo command rejected: need fully-qualified hostname

I got this by turning on maximum logging at the Exchange server-- this is the full text of the transmission:

1/27/04 4:08:13 PM : A connection to 64.52.192.99 was established.
1/27/04 4:08:13 PM : <<< IO: |220 s1.mail-in.isp.nyc.eggn.net ESMTP
|
1/27/04 4:08:13 PM : <<< 220 s1.mail-in.isp.nyc.eggn.net ESMTP
1/27/04 4:08:13 PM : >>> EHLO MLTW_CLUSTER

1/27/04 4:08:13 PM : <<< IO: |250-s1.mail-in.isp.nyc.eggn.net
250-PIPELINING
250-SIZE 20480000
250-ETRN
250-XVERP
250 8BITMIME
|
1/27/04 4:08:13 PM : <<< 250-s1.mail-in.isp.nyc.eggn.net
250-PIPELINING
250-SIZE 20480000
250-ETRN
250-XVERP
250 8BITMIME

1/27/04 4:08:13 PM : >>> MAIL FROM:<weisberg@mltw.com> SIZE=3258

1/27/04 4:08:13 PM : <<< IO: |250 Ok
|
1/27/04 4:08:13 PM : <<< 250 Ok
1/27/04 4:08:13 PM : >>> RCPT TO:<jhonig@FKIWSB.com>

1/27/04 4:08:13 PM : <<< IO: |504 <MLTW_CLUSTER>: Helo command rejected: need fully-qualified hostname
|
1/27/04 4:08:13 PM : <<< 504 <MLTW_CLUSTER>: Helo command rejected: need fully-qualified hostname
1/27/04 4:08:13 PM : >>> QUIT

1/27/04 4:08:13 PM : <<< IO: |221 Bye


As far as I can see, my mail server domain name is as fully-qualified as it can be.
If anyone has any thoughts, feel free to let me know.
Thanks,
Whitemtntn

 

[rdroske]

My guess is you are missing a domain name in your DNS setup. If this is NT 4 thats Control Panel/Network/Protocols/TCP/IP/Properties and the DNS tab.
Is there a domain specified there?

 

[Whitemtntn]

It would seem that that would make sense but..
Both the host and domain are specified.
-Whitemtntn

 

[Whitemtntn]

I discovered this when we were unable to email a particular domain.
&quot;Undeliverable&quot; &quot;Recipient name not recognized&quot;
I examined the IMC log and found this message within the failed email--

504 <MLTW_CLUSTER>: Helo command rejected: need fully-qualified hostname

This is Exchange 5.5 (SvcePk4) on an NT server 4.0 (Svcepk6a)
On the Exchange server the host name and domain is filled out on the DNS tab in TCP/IP properties. I tested reverse lookup of our exchange server-- it is properly working.

I did a test-- I telnetted to the remote mail server and attempted to send mail to them with SMTP commands. When I used the HELO/EHLO command with an FQDN, the mail went thru. When I used the HELO/EHLO command with just a host name-- I got the same error.

So, how do I figure out why Exchange is not sending an FQDN with the EHLO command? It doesn't seem to matter while emailing most domains-- but it does with this one.

Thanks-
Jack
weisberg@mltw.com

 

[rdroske]

Any chance you are going through a relay (connections Tab on IMS properties, forward all messages to host selected)?

 

[Whitemtntn]

No relay. Straight out.
-Whitemtntn

 

[fjrubior]

Got the same problem.
You are running Exchange in a cluster environment, right? (me too).
I think the thing is how to fully-qualified the exchange cluster virtual name. I've been looking for this but still no answer.

 

[Whitemtntn]

YES. You got it. The infamous Microsoft NT4 Enterprise Edition Cluster and Exchange is clustered.. yah I still haven't found the answer either.. I will certainly post it if I do--

 

[spambakian]

Did anyone find a resolution to this problem? I'm having the same issue, although my mails are returned due to a communication failure".

 

[RichardMoran]

I don't know if this is relevant, but is MLTW_CLUSTER the hostname? ( I'm not an advanced Exchange user! )

I used to get all mail rejected from a particular domain because our hostname had an underscore in it, and that wasn't compliant with the related RFC (821 I think). It was only the one domain we had problems with, but in theory it should have been all if everybody's mailservers were compliant.

I just changed the hostname in the DNS tab to resolve our issue.

Thought I'd mention it just in case.

Rik

 

[fjrubior]

After some research and consulting I found that a Windows NT 4.0 Cluster will not pass a FQDN. So, there is no direct solution for this issue.
A workaround would be implementing an SMTP relay and configuring the Exchange cluster to forward e-mail to it.
Now, upgrading to Windows 2000/2003 Cluster would also do it! :s

 

[dbrennan]

I have been having the same problem and funny enough I use exchange 2003. The one thing we have in common is that it the same ISP that I could not send and receive email to.

I am using a filtering system and I resolved the email connection problem by making the filtering system have a FQDN. Then I could email back and forth but they could not email my list server. The company has set up their mail server to only forward to servers with MX records. This is a psuedo-security measure which has long been forsaken by mail server venders. The problem lies with this ISP not you.