Server Components

Server components for Microsoft Exchange Server often reside on a dedicated computer. These components are shown in the following diagram.

Server components of Microsoft Exchange Server

The following components run on the Microsoft Exchange Server computer:

• Directory Stores and manipulates information about an organization’s Microsoft Exchange Server directory objects, such as recipients, distribution lists, public folders, and services.
• Directory exchange agent (DXA) Maintains synchronization between a Microsoft Exchange Server directory and a Microsoft Mail 3.x directory or a directory using the Microsoft Mail 3.x protocol.
• Information store Contains all server-resident information created by users such as messages, forms, and documents. The MAPI programming interface is used by both clients and services to access the information store.
• Message transfer agent (MTA) Routes messages to other servers or to X.400 mail systems. The MTA is a native X.400 message transfer agent. Messages to be sent through gateways and mail connectors to other systems are also routed to the MTA, but then are routed back to the information store for direct transfer to the gateway or mail connector. There is no direct programming interface for accessing the MTA.
• Gateway Provides a connection between a Microsoft Exchange Server system and a foreign mail system. The gateway translates messages and maps addresses between the two systems transparently to the user. Gateways can also be used to connect one Microsoft Exchange Server organization with another. While mail connectors are often specific to a single foreign mail system, gateways are often general enough to be customized for different systems. See the Gateway Programmer’s Reference.
• Connector Similar to a gateway. Mail connectors are often developed for a single foreign mail system, such as SMTP.

The following basic services are associated with Microsoft Exchange Server:

• Directory
• Information store
• Message transfer agent (MTA)
• System attendant

These services are managed by the Windows NT service control manager.

Each server component of Microsoft Exchange Server can be accessed by developers so you can design your own server applications and customize your system to meet the specific needs of your organization.