If you are configuring a virtual Email Security appliance, please see the Cisco Content Security
Virtual Appliance Installation Guide before continuing with this chapter.

•

If you are configuring an M-Series Cisco Content Security Management appliance, please see

Chapter 43, “Centralizing Services on a Cisco Content Security Management Appliance”

•

We recommend reviewing

Chapter 4, “Understanding the Email Pipeline”

before installing, as some

features and functions may affect the placement of the appliance within your infrastructure.

Plan to Place the Email Security Appliance at the Perimeter of Your Network

Your Email Security appliance is designed to serve as your SMTP gateway, also known as a mail
exchange (MX). For best results, some features require the appliance to be the first machine with an IP
address that is directly accessible to the Internet (that is, it is an external IP address) for sending and
receiving email.

The per-recipient reputation filtering, anti-spam, anti-virus, and Virus Outbreak Filter features (see

SenderBase Reputation Service, page 6-1

IronPort Anti-Spam Filtering, page 13-3

Sophos Anti-Virus

Filtering, page 12-2

, and

Outbreak Filters, page 15-1

) are designed to work with a direct flow of