Troubleshooting E-Mail Delivery Problems
 

Sonora Communications, Inc.

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Troubleshooting E-Mail Delivery Problems

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This document assumes you are troubleshooting a problem with an existing mail server and a working mail client. You might use this info to troubleshoot a problem sending or recieving messages to or from a particular sender or recipient, for example.

What's Needed

Whether you are troubleshooting the problem yourself or asking a support person to troubleshoot the problem for you, the same information is needed.

First, you need the original error message (NDR or non-delivery report) that came back from the sender's mail server. It's important that you have the original error message because it will have all of the message headers that are absolutely necessary to troubleshoot any problem.

If you are having a technician help troubleshoot, you must forward the original error message to the technician as an attachment in order to preserve the headers. Please read that statement carefully because it is very precisely worded.

For in-depth troubleshooting, you will need access to the mail server log files as well. Furthermore, you will need to know the time zones of the e-mail messaging participants in order to correlate the log entries and error messages.

How to Forward a Message as an Attachment

Outlook 2003

  1. With Outlook 2003 open, and the spam (or NDR) message in the list in front of you, click the New button, to send a new email.
  2. Use alt-tab, or click on the taskbar item of the main Outlook window back to bring it to the foreground.
  3. Drag (click and hold) and drop the spam (or NDR) message(s) that you want to forward onto the new message window. This will make the spam/NDR emails attachments to your new email. If you are like many others, and have Outlook maximized all the time, then while you are still holding down the mouse button, hold the mouse cursor over the new outlook message taskbar item for half a second or so until the new-message window pops up into the foreground, then move the mouse cursor over the new message window & release the button.
  4. Once you have done this, simply type in the destination e-mail address, and send the email.

Outlook 2007

  1. Select the message
  2. Under Actions on the menu bar, click Forward as Attachment

Thunderbird

  1. Select the message
  2. Under Message on the menu bar, select Forward As--> Attachment

Outlook Express

  1. Open the message
  2. Under Message on the menu bar, select Forward as Attachment

Check to See if Your Mail Server is Blacklisted

In the modern, spam-infested wold, mail system administrators go to great lengths to filter junk mail from their user's inboxes.? One of the tools mail system administrators use are 'blacklists' or 'blocklists'.? These lists, and there are many of them, are checked in a programmatic way by mail servers each time they receive a message.? If the sending mail server is on blocklist, the receiving server will refuse the message.? Blocklists can be based on many different criteria, such as DNS or IP address ranges or even the country of origin.

As you can imagine there is tremendous room for errors and problems!

To troubleshoot blacklisting problems, you first need to know the IP address of your mail server.? You can get that from the message headers or by querying the domain name system (DNS).? To query DNS, use dig' or 'nslookup'.

First, query the domain for mail exchanger (MX) records:

dig yourdomain.com mx

which yeilds this line from the Answer Section:

yourdomain.com.??? ??? 3600??? IN??? MX??? 10 nullmx.yourdomain.com.

which indicates the mail server is named "nullmx.yourdomain.com".? Now you need to determine the IP address of this server.? Again we use 'dig':

dig nullmx.yourdomain.com

which results in this line frm the Answer Section:

nullmx.yourdomain.com.??? 3405??? IN??? A??? 209.181.247.105

You can then use that IP address to check for blacklistings.? One convenient web site that allows you to check many different blacklists at the same time is here.

Sometimes we see problems that "just shouldn't be"...problems where a message is refused without any obvious cause.? These situations almost always involve "big" mail services such as Cox, AOL, AT&T, Earthlink, etc...services that are big enough to be "bullies".? To be perfectly honest, the solution may simply to not use the "big" e-mail service provider in favor of one that actually 'cares'.

Yes, I realize you will probably have a hard time convincing your messaging partner that they should dump that 'big' service provider, but the recommendation stands none the less.? You might just tell the recipient that the problem is on their end and ask them for an alternate e-mail address.

Multiple Copies of E-Mail Messages

Check here.

Last Updated on Friday, 11 December 2009 17:01