How to view complete email message headers

To see what complete email message headers look like (spam, in this case) and what they represent, see the following document:
Email Message Headers

You can also decipher headers online.

Outlook 2010, 2013, 2016

1. Double-click the message to open it in a separate window.
2. Click File to access the Backstage view and click the Properties button.
3. To make this process easier in the long-term, see: Hey Outlook 2010, where are my message headers? (applicable to Outlook 2013, 2016 as well).

Outlook 2000, 2002, 2003, 2007

1. Right-click on the message and choose Options (Message Options in Outlook 2007).

Windows Live Mail, Windows Mail, Outlook Express

1. Right-click on the message and choose Properties.
2. Click on the Details tab.
3. Optional: Click on the Message Source button and resize the window to make it easier to read.

Netscape 6/7

1. Click View then Headers; select All.
2. Select the message.
3. Click View then Message Source.

Thunderbird

1. Select the message.
2. Click View then Headers; select All.

Eudora

1. Open the message.
2. Click the BLAH BLAH BLAH button above the message.

IncrediMail

1. Right-click on the message and choose Properties.
2. Click on the Details tab.

Apple Mail

Entourage

1. Select the message.
2. Click Message (Entourage 2008) or View (Entourage 2004) then Internet Headers.

Network Tallahassee Webmail (Namecheap Private Email / Open-Xchange (OX))

1. Select the message.
2. Click the (Actions) button and select View source.

Network Tallahassee Webmail (Ipswitch / virtual domains hosted by Network Tallahassee)

1. Select the message.
2. Click Show Header.

Gmail / Google Apps (webmail)

1. Select the message.
2. Click the downward-pointing triangle (arrow) to the right of the Reply button and select Show original.

Yahoo! Mail (webmail)

1. Select the message.
2. Click More (below the message) then View Full Header.