Winston Lawrence

Project Manager & Occasional developer

The problem with the non-delivered email

When the email doesn't go through

How email travels from your desktop in Brooklyn to your friend's iPad in Toronto or even to your co-worker's Email symbollaptop, two cubicles away is not something that you probably spend too much time thinking about - unless you happen to be the system administrator or your in-box throws out a 'undeliverable mail'  message.

I was wearing the 'sysadmin' hat for this particular company assignment and ended up learning something new while resolving an unusual undeliverable email problem.

......As is usual in these posts, the name of the various parties including the company names have been changed to protect guilty and innocent alike.

Monday Morning Mail Madness

I had come into the office early to finish up  documentation on the migration and decomisioning of the last two Windows 2000 domain controllers over the weekend and the completion of this assignment.  Stefan, the VP of Sales, knocked on the door and asked if I could give him a hand with a problem that he was having in sending an email.  Stefan is a nice guy and actually pretty good with technology so I figured it was probably a real problem. I asked him to give me about 30 minutes to finish up what I was working on and then I would come over to his office.

When I sat down with Stefan it turned out that he was having trouble sending email to a new client and that the emails that he had sent out three days before were now being returned to his in-box by the company Exchange server with a non-delivery report (NDR) saying:

Your message did not reach some or all of the intended recipients. Subject: New Order confirmation Sent: 4/29/2010 4:37 PM The following recipient(s) could not be reached: JohnnyCEO on 5/01/2010 8:09 AM This message was rejected due to the current administrative policy by the destination server. Please retry at a later time. If that fails, contact your system administrator.

A quick check on the Exchange server queue showed that there were indeed two other messages from Stefan, still sitting in the Exchange queue. No other messages were in the queue and I could see  that other emails were being sent and received without any problems. I promised Stefan that the failure did not appear to be with anything that he was doing and that I would look into the problem further and then get back to him.

Determine the scope of the problem: SMTP email test

Back at my desk, I brought up my trusty SMTP email test client [*]
in order to narrow the scope of the problem. If my test client worked then the problem would be within our company system and probably within the Exchange server since my client test would only bypass the Exchange server but not the rest of the infrastructure (like switch, firewalls and ISP).

The SMTP to SMTP (BMAIL.EXE) TEST C:appscomm>bmail -s -t -f -b "test to see if email makes it to you. Reply if you get it please.!" -a " domain to domain email test" -d Command Line SMTP Emailer V1.07 Copyright(C) 2002-2004 Opening connection to [] on port 25 Socket Closed

The SMTP test,  as shown above,  failed just like the email that Stefan sent. The failure does seem to indicate that the problem does not seem to be within the Exchange server.

Is it possible that the client company is filtering and rejecting the email from our company,  and if so why?

Next post: Did the company land on an email (RBL) block list (again)?

[*] Note: bmail.exe is a free Windows SMTP client that you can get from it is really useful for SMTP and email troubleshooting.

Winston Lawrence

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