Complete headers provide more information on the origin of a message and are a useful tool for tracking and stopping spam e-mail. Most e-mail readers only show the To: and From: headers, which can be easily forged. The complete message headers will look something like this:
Received: from some.host.com (hostname [xx.xx.xx.xx])
by egr.msu.edu (8.9.3/8.9.3) with ESMTP id NAA23597;
Thu, 7 Oct 1999 13:39:26 -0400 (EDT)
Date: Thu, 7 Oct 1999 13:39:26 -0400
From: Spammer [email@example.com]
Subject: My spam message!!
Tap the ALT key to reveal the menu bar if it doesn't already appear. Click View on the toolbar and click Headers, then select All.
Open the message you want to reveal the headers for, and click the View Full Headers link at the top of the page.