Forum Moderators: mack
Your e-mail client should have an option called "Show raw source," "Show original message," or "Show long headers." Select any of those to see the actual contents of the message. You can run whois on the IP addresses found.
You'd typically look for the last "Received:" header and whois the blue IP addresses (this snippet widgetized):
Received: from [192.168.123.192] (4.8.9.6.ispwhowonttellyou-anything.net [4.8.9.6]) by mailserver.net) with ESMTP id ig785jgnd23 for <you@yerdomain.com>; Mon, 2 Aug 2004 12:05:30 -0400 (EDT))
This is a valuable exercise anyways to get a better understanding of what an e-mail really is (just a text file).