Sun Java System Messaging Server 6.3 Administration Guide

8.1 The MTA Functionality

The Message Transfer Agent, or MTA is a component of the Messaging Server (Figure 8–1). At its most basic level, the MTA is a message router. It accepts messages from other servers, reads the address, and routes it to the next server on way to its final destination, typically a user’s mailbox.

Over the years, a lot of functionality has been added to the MTA, and with it, size, power, and complexity. These MTA functions overlap, but, in general, can be classified as follows:

A number of subcomponents and processes support these functions and are shown in Figure 8–2. This chapter describes these subcomponents and processes. In addition, a number of tools allow system administrators to enable and configure these functions. These include MTA options, configutil parameters, mapping tables, keywords, channels, and rewrite rules. These are described in later MTA chapters:

Figure 8–1 Messaging Server, Simplified Components View (Communications Express not Shown)

Graphic shows a simplified view of the Messaging Server.

Figure 8–2 MTA Architecture

Graphic shows a simplified architecture and data flow
of the MTA.