Chapter Summary

Exchange 2000 Server is a complex, component-oriented client/server messaging and collaboration system that includes active Windows 2000 services. These services communicate with each other using LRPCs, RPCs, Windows Sockets, ExIPC, regular files, and e-mail messages. With the exception of the Event Service, all components have to communicate with Active Directory.

Information Store and SMTP service, in conjunction with SA, Active Directory, and IIS Admin Service, are required to provide basic messaging functionality to Outlook users. Exchange 2000 Server maintains mailboxes and public folders in the information store and always requires message processing through the SMTP transport. Active Directory hosts the address books and provides recipient information to clients and system components. The SA, again, takes care of the Exchange 2000 Server system and the IIS Admin Service controls the SMTP transport. When Information Store and Active Directory are in operational states, users can gain access to their messages and other data stored in mailboxes and public folders, but without the SMTP service, there is no message transfer.

The Exchange 2000 Server-specific SMTP and NNTP service extensions, as well as the Exchange Routing Engine, IMAP4, and POP3, use ExIPC to rapidly exchange data directly with the Information Store through memory rather than through RPCs or other communication methods. This provides the best performance and reduces overhead required for interprocess communication. Exchange 2000 Server implements an advanced queuing engine for the SMTP transport, which processes every message sent through the server and determines how to reach each recipient.