Read RFC 5321 for SMTP. What does MTA stand for? Consider the follow- ing received spam email (modified from a real spam email). Assuming only the originator of this spam email is malacious and all other hosts are honest, identify the malacious host that has generated this spam email.

From - Fri Nov 07 13:41:30 2008

Return-Path: <tennis5@pp33head.com>

Received: from barmail.cs.umass.edu

(barmail.cs.umass.edu [128.119.240.3]) by cs.umass.edu (8.13.1/8.12.6) for <hg@cs.umass.edu>; Fri, 7 Nov 2008 13:27:10 -0500

Received: from asusus-4b96 (localhost [127.0.0.1]) by

barmail.cs.umass.edu (Spam Firewall) for <hg@cs.umass.edu>; Fri, 7 Nov 2008 13:27:07 -0500 (EST)

Received: from asusus-4b96 ([58.88.21.177]) by

barmail.cs.umass.edu for <hg@cs.umass.edu>; Fri,

07 Nov 2008 13:27:07 -0500 (EST)

Received: from [58.88.21.177] by

inbnd55.exchangeddd.com; Sat, 8 Nov 2008 01:27:07 +0700

From: "Jonny" <tennis5@pp33head.com>

To: <hg@cs.umass.edu>

Subject: How to secure your savings