Link to home
Start Free TrialLog in
Avatar of avogini
avogini

asked on

Receiving dreaded "The connection was dropped by the remote host." error in Exchange 2003.

This has been an error tossed around a 100 times over, but here we go again, since the other KB's simply are not helping.

On currently a single external domain, (not gmail, yahoo, or the others, but a private business), we are receiving the message in the queue "The connection was dropped by the remote host." After 24 hours, the message dies and the NDR that it could not be sent in a timely fashion is sent out, pattern repeats.

The standard ideas are either fixed or not working: Symantec Antivirus is not running; I have turned the Symantec Mail Security on and off and that does not help; our rDNS is correctly matching our email server ("mail.abc.com"); the FQDN of mail.abc.com is listed in the Advanced Delivery section of teh SMTP Virtual Server Properties. Oh, and we have the latest hotfixes for Windows Server 2k3 AND Exchange Std. 2k3.

Now what is interesting is according to the other company, they can receive email fine from everyone else but us, and they can send email TO us. We simply cannot reply back. Now one thing I did find out when I attempted to telnet is that the domain names ARE different for them...email is jdoe@dog.com, but MX record is mail.CAT.com. I have to wonder if that is causing an issue, but I am simply stumped of what I can do from here.

Help is needed!
Avatar of portiz60
portiz60

Hi, could you put here the complete NDR message?, please include all the message.
Avatar of Alan Hardisty
Please have a read of my FAQ for this exact problem - it could be that you are simply missing an SPF record and that will solve the problem:
http://www.it-eye.co.uk/faqs/readQuestion.php?qid=2 
Avatar of avogini

ASKER

NDR:

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

      Subject:      RE: 10-06-09 Reddy @ ORMC-Patient Zachery
      Sent:      10/6/2009 3:54 PM

The following recipient(s) cannot be reached:

      Niki Desrosiers on 10/7/2009 3:59 PM
            Could not deliver the message in the time limit specified.  Please retry or contact your administrator.
            <mail.trigonholdinginc.com #4.4.7>

This NDR is being generated by my Exchange 2k3 server.

I'm actually not familiar with SPF records. Why would that be causing an issue now? And I will look into creating one.
The SPF record can be and is often used to determine the legitimate sender of emails.  Some companies choose to reject companies that send emails out from domains that do not have an SPF record in their domains DNS records.  Rightly or wrongly - this can often cause problems in sendign mail and I have answered several questions where simply adding an SPF record resolves problems like yours.
Everything else about your domain is as it should be from what I can tell - so if you can please add an SPF record to your domain and then try sending out the message again - see what happens.
Avatar of avogini

ASKER

Sorry Alan, still no joy. I added the SPF to my domain per the instructions, made sure DNS replicated, and resent two more test emails. Still getting the same error. Again though only for this one domain. I have tried to get in contact with the company's email admin and I am still waiting on a response. Just very odd...
Still no SPF record according to the live information I am looking at.  You may have set it up incorrectly:
Your domain does not have an SPF record. This means that spammers can easily send out E-mail that looks like it came from your domain, which can make your domain look bad (if the recipient thinks you really sent it), and can cost you money (when people complain to you, rather than the spammer). You may want to add an SPF record ASAP, as 01 Oct 2004 was the target date for domains to have SPF records in place (Hotmail, for example, started checking SPF records on 01 Oct 2004).  
Avatar of avogini

ASKER

We only host internal DNS, which I am betting is the problem with the SPF.

Now then do I contact the company that DNS servers host my domain name (per whois) or my ISP? (The are not the same.)
Your DNS servers are at expedient.com.
Avatar of avogini

ASKER

Nevermind, SPF is now added.
Yes - that is now available for all to see.  It may take a while for the world to catch up - but please send out a test message again and see if that works.  If not - please send messages every few hours for the next 24-48 hours.  After this time - it is safe to assume that this is not the solution.
Avatar of avogini

ASKER

Yeah I just tried now and again no joy. I will test again tonight/tomorrow and we will go from there. I still haven't heard back from their email admin, and as I said, this is the ONLY domain we are having issues with.
They could just be over-zealous with their spam filtering!
Avatar of avogini

ASKER

That is a definitely possibility. I am still fighting to speak with their email Admin because I am starting to wonder if there is some sort of security killing the connection that I am not aware of at this time. I will update as necessary.
SOLUTION
Avatar of Alan Hardisty
Alan Hardisty
Flag of United Kingdom of Great Britain and Northern Ireland image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of avogini

ASKER

I just got off the phone with the other domain's mail admin and he was just about as clueless as I was at this point. I had him shut off his spam filter and refreshed the queue connections, but still kicking back the same error. I also telnet'ed into his server and ran a basic test to send him an email, but he never got it either. What was odd was the telnet ended with "250 Mail queued for delivery."

I did discover his set up though: single backend exchange 2k3 server, cisco firewall with port 25 opening and redirecting to his server. No Front-end machine, no ISA, nothing. They have a very similar set up to ours, but it is something definitely between our server and their's, b/c no one on either end are having similar problems with any other email domains. Really strange and frustrating...
If they're runing a Cisco PIX they may want to try issuing a "no fixup protocol smtp 25" (or the ASA equivelant)...

Also, I believe 250 Mail Queued For Delivery is the normal ending of mail delivery, and if you telnet'ed into his server, issued valid SMTP commands and he never got it then I'd say it's definately a problem with his server.
ASKER CERTIFIED SOLUTION
Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial