Applies to: Exchange Server 2007 SP3, Exchange Server
2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2006-09-15
The Microsoft Exchange Server 2007 Edge Transport server role is deployed in your organization's perimeter network and handles all Internet-facing mail flow, providing protection against spam and viruses.
The Edge Transport server role accepts mail coming into the Exchange 2007 organization from the Internet and routes all outbound messages to the Internet. The Edge Transport server role acts as a smart host and SMTP relay for the Exchange organization. You configure Send connectors and Receive connectors on the Edge Transport server to control message processing.
Anti-Spam and Antivirus Functionality
Most viruses use spam-like tactics to gain access to your organization and to entice users to open a piece of mail. If you can filter out most of your spam, or unsolicited commercial e-mail, you are more likely to capture viruses before they enter into your organization. Spammers use a variety of techniques to send spam into your organization. The Exchange 2007 Edge Transport server role helps prevent users in your organization from receiving spam by providing a collection of agents that work together to provide different layers of spam filtering and protection:
- Attachment Filter agent This agent
filters messages based on attachment file name, file name
extension, or file MIME content type. You can configure this agent
to block a message and its attachment, to strip the attachment and
allow the message to pass through, or silently delete the message
and its attachment.
- Connection Filter agent This agent
filters messages based on the IP address of the remote server from
which a message is sent. A variety of IP Block lists and IP Allow
lists and optional services are used to determine what action, if
any, to take on a particular message based on its source IP
- Content Filter agent This agent uses
Microsoft SmartScreen technology to assess the contents of a
message. The Exchange Intelligent Message Filter is based on
patented machine learning technology from Microsoft Research.
The Intelligent Message Filter learns distinguishing
characteristics of legitimate e-mail and of spam. Based on these
characteristics, the Intelligent Message Filter helps determine
whether an incoming message is spam or legitimate e-mail.
- Recipient Filter agent This agent
compares the recipients that are identified in the RCPT TO: SMTP
header to known recipients identified in an IP Block list and to
the local recipient directory which stores valid recipients that
exist inside the organization to determine what action, if any, to
take on a particular message.
- Sender Filter agent This agent compares
the sender identified in the MAIL FROM: SMTP header to known
senders identified in an IP Block list to determine what action, if
any, to take on a particular message.
- Sender ID agent This agent relies on
the RECEIVED: SMTP header and a query to the sending system's DNS
service to determine what action, if any, to take on a particular
Messaging Policy and Compliance
Many organizations have legal, regulatory, or internal requirements to filter, process, and store e-mail that is between users in the organization. Additionally, many organizations have additional requirements for how to handle mail sent to or from the Internet. A collection of messaging policy and compliance agents in Exchange 2007 helps organizations more easily comply with these legal, regulatory, and internal requirements by providing ways to configure rules and settings that help you meet these requirements. The following messaging policy and compliance agents are available on the Edge Transport server role:
- Address Rewrite agent This agent
enables the modification of the SMTP address for any sender or
recipient of messages sent or received by your organization.
Address rewriting can be useful in scenarios where an organization
wants to hide internal domains, to enable multiple organizations
appear as a single organization, or to integrate services that are
provided to an organization by a third-party.
- Edge Rules agent You configure the Edge
Rules agent on the Edge Transport server role to create rules that
control the flow of messages that are sent to or received from the
Internet. The Edge Transport rules help protect corporate network
resources and data by applying an action to messages that meet
specified conditions. These rules are configured for each server.
Edge Transport rule conditions are based on data, such as specific
words or text patterns in the message subject, body, header, or
From address, the spam confidence level (SCL), or attachment type.
Actions determine how the message is processed when a specified
condition is true. Possible actions include quarantine of a
message, dropping or rejecting a message, appending additional
recipients, or logging an event. Optional exceptions exempt
particular messages from having an action applied.