====== Troubleshooting E-Mail Delivery Problems ======

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.

**Second**, 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.

**Third**, 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 =====

==== Zimbra ====

**Zimbra Web Client -> (select message) -> Forward**

Then:

**Options -> Include Original As Attachment**

==== Gmail ====

**Gmail -> (open the message) -> More (ellipse) -> Download Message**

Then:

**Compose (new message) -> Attach File (previously downloaded ''.eml'' file)**

==== Outlook 2003 ====

  - 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.
  - Use alt-tab, or click on the taskbar item of the main Outlook window back to bring it to the foreground.
  - 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.
  - Finally, just type in the destination e-mail address of the technician and send the email.

==== Outlook 2007 ====

  - Select the message
  - Under **Actions** on the menu bar, click **Forward as Attachment**

==== Outlook 2013 and 2016 ====

There is a keyboard shortcut you can use.  Just **select the message you want to forward and press Ctrl+Alt+F**.

Otherwise, to forward a message as an attachment, select the message then in the Respond group, click More and then click Forward as Attachment.

==== Thunderbird ====

  - Select the message
  - Under **Message** on the menu bar, select **Forward As -> Attachment**

==== Outlook Express ====

  - Open the message
  - Under **Message** on the menu bar, select **Forward as Attachment**

==== MacOS Mail ====

  - **Right-click** the message from the list and select **Forward as Attachment**

===== Blacklist Problems =====

In the modern, spam-infested world, 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 may 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!

==== Troubleshooting Blacklist 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''.  On Windows PCs, just use ''nslookup''.

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

<file>
dig yourdomain.tld mx
</file>

which yields something like this line from the Answer Section:

<file>
yourdomain.tld.         3600    IN      MX     10 mailserver.yourdomain.tld.
</file>

which indicates the mail server is named "mailserver.yourdomain.tld".

Now you need to determine the IP address of this server.  Again we use 'dig':

<file>
dig mailserver.yourdomain.tld
</file>

which results in a line like this from the Answer Section:

<file>
mailserver.yourdomain.tld.   3405   IN      A    xxx.xxx.xxx.xxx
</file>

You can then use that IP address to check for blacklistings.  Here are some convenient web sites that allow you to check various blacklists:

http://whatismyipaddress.com/blacklist-check

http://www.mxtoolbox.com/blacklists.aspx

https://ers.trendmicro.com/

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".

No one wants to hear this, but to be perfectly honest, the solution may simply be 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 =====

See also **[[internet:mail:mail_copies|Multiple Copies of E-Mails]]**