Part Three

Network attacks are more common than ever, and that trend is likely to continue. Therefore, after configuring mail flow in your Exchange organization, it is crucial that you take measures to help secure this mail flow. Messages that are routed to and from Microsoft® Exchange servers and other external systems also travel across your local network and over the Internet. To prevent malicious Internet users from intercepting your organization's mail and attacking your servers, it is important that you secure your Internet connections. The three types of Internet connectivity are:

• Using connectors over the Internet to have e-mail connectivity between your organization and other external systems.

• Using connectors to connect Exchange routing groups within your organization over the Internet.

• Allowing Exchange clients to use Internet mail protocols or Microsoft Office Outlook® Web Access to access Exchange mailboxes in your organization.

Generally, each of these types of connectivity require a different level of security. The sections in Part 3 address various ways to secure your Exchange organization:

• Securing Your Infrastructure

  This section focuses on methods that you can use to help protect your infrastructure by disabling unnecessary services in Internet Information Services (IIS) and by using firewalls and virtual private networks.

• Securing Your Exchange Server

  This section discusses general security practices that you can use to protect your Exchange servers.

• Configuring Filtering and Controlling Spam

  This section explains how to control unsolicited commercial e-mail, also known as spam, by using Exchange recipient, sender, and connection filtering.

  Note

  For more information about securing Exchange, see the Exchange Server 2003 Security Hardening Guide.