In Microsoft Server 2010, the Edge Transport server role is deployed in an organization's perimeter network. Designed to minimize the attack surface, the Edge Transport server handles all Internet-facing mail flow, which provides SMTP relay and smart host services for the organization. Additional layers of message protection and security are provided by a series of agents that run on the Edge Transport server and act on messages as they are processed by the message transport components. These agents support the features that provide protection against viruses and spam and apply transport rules to control message flow.

The computer that has the Edge Transport server role installed does not have access to Active Directory. All configuration and recipient information is stored in Active Directory Lightweight Directory Services (AD LDS). To perform recipient lookup tasks, the Edge Transport server requires data that resides in Active Directory. This data is synchronized to the Edge Transport server using EdgeSync.

EdgeSync is a collection of processes that are run on a computer that has the Hub Transport server role installed to establish one-way replication of recipient and configuration information from Active Directory to the AD LDS instance on an Edge Transport server. The Microsoft EdgeSync service copies only the information that's required for the Edge Transport server to perform anti-spam configuration tasks and the information about the connector configuration that's required to enable end-to-end mail flow. The Microsoft EdgeSync service performs scheduled updates so that the information in AD LDS remains current.

You can install more than one Edge Transport server in the perimeter network. Deploying more than one Edge Transport server provides redundancy and failover capabilities for your inbound message flow. You can load-balance SMTP traffic to your organization between Edge Transport servers by defining more than one mail exchange (MX) resource record with the same priority in the Domain Name System (DNS) database for your mail domain. You can achieve consistency in configuration between multiple Edge Transport servers by using cloned configuration scripts.

If you need geographical load balancing support, please contact the Progress Kemp sales team at http://www.kemptechnologies.com.