Sun Java System Messaging Server (Messaging Server) is a powerful, standards-based Internet messaging server for both enterprises and service providers. Designed for high-capacity, reliable message handling, Messaging Server consists of several modular, independently-configurable components that provide support for several e-mail protocols.
The Java ES installer provides Messaging Server as a single installable component. However, after installation, each Messaging Server instance can be configured to provide any of a number of different messaging services, in effect representing the following set of Messaging Server subcomponents:
Message Store. Provides message storing and retrieving.
Message Transfer Agent (MTA). Supports the sending of emails by handling SMTP connections, routing emails, and delivering messages to the proper message stores. Can be configured to deliver email to internal storage (inbound) or to external mail stores (outbound).
Message Multiplexor (MMP). Supports the retrieving of emails by accessing the message store (or a set of stores) for email clients, using either IMAP or POP protocols.
Message Express Multiplexor (MEM). Supports the retrieving and sending of emails by web-based (HTTML) email clients.