Some emails are returned

Posted on 2010-08-17
Medium Priority
Last Modified: 2012-05-10
How can I troubleshoot some issues with my exchange server when some emails are returned at random. It does not happen on a daily basis but important emails to some users are been returned. The email address is correct.

Today's email error is as follow:

This is an automatically generated Delivery Status Notification.

Unable to deliver message to the following recipients, due to being unable to connect successfully to the destination mail server.

      emailaddress@server.net (removed on purpose)

Reporting-MTA: dns;servername.net (actual server name changed) Final-Recipient: rfc822;emailaddress@server.net Action: failed Status: 4.4.7 X-Display-Name: emailaddress@server.net

Any help is greatly appreciated.

Question by:rauladan
  • 5
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Expert Comment

ID: 33456105
Hi rauladan:

These are for emails being sent from your company to outside email addresses and you receive the NDR's back?

If so, is your reverse DNS set up correctly for your mail server IP?  You server IP should resolve to your mail server A record when doing a reverse lookup.

Check your IP here:



Author Comment

ID: 33456544
It points to our ISP (bellsouth.net). It does not show the domain name.

I will work on that and let you know the results. Thank youuuuu.


Expert Comment

ID: 33456599
you should be able to submit a request to your ISP for them to modify your PTR (since they maintain the reverse zone for your public IP range).

should read:

PTR     host.domain.com

where is your public IP and host.domain.com is your mail server hostname.
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Author Comment

ID: 33469326
The reverse DNS resolve correctly now to the proper domain name but the problem is still there. Do you have any suggestions on how to troubleshoot this issue?

Here is a copy of the message:

Your message did not reach some or all of the intended recipients.
      Subject:  Documents
      Sent:     8/18/2010 8:48 AM
The following recipient(s) cannot be reached:
      username@comcast.net on 8/18/2010 9:51 AM
            Could not deliver the message in the time limit specified.  Please retry or contact your administrator.
            <domainname.net #4.4.7>

Expert Comment

ID: 33469415
Since the record was pointing to your ISP instead of your server, you may have been added to one or more blacklists.  Try searching here:


to see if you're server is listed.  If so, you will have to submit requests to remove now that the issue is resolved.

Accepted Solution

jffrybauer earned 2000 total points
ID: 33469456
One more thing, this won't resolve the current problem, but to help avoid issues in the future, create an SPF record for your domain and publish it in your public DNS:




Author Comment

ID: 33478093
Was wondering why I never got a response. Just signed on and saw your response. I appreciate it very much. Anyway, no they are not blacklisted. I had checked on that before.

Thank you. I am adding the SPF record and will let you know the outcome.

Thank you again.

Expert Comment

ID: 33478530
You can try more lookups here:


and here:


Also, depending on how long your ISP has their DNS zone time to live set for, it could take 24 - 48 hours from the time they made the change to propagate across the internet.

Have you done another reverse lookup to make sure they entered the reverse record correctly?

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