Sun™ ONE Messaging Server: Practices and Techniques for Enterprise Customers

MTA

The MTA, which is sometimes referred to as the mail gateway or SMTP server, routes the mail to its destination or rejects it if not properly formatted or addressed, or simply not for this messaging system. This is typically done via SMTP or related protocols such as the Extended Simple Mail Transfer Protocol (ESMTP) and Local Mail Transfer Protocol (LMTP). Basically, the MTA is to email what a Cisco router is to Ethernet packets.

The MTA is also what determines how messages are handled for specific users based on their preferences stored in the directory (for example, a vacation message). And, it is the place where expansion of mail lists, groups, and aliases occurs. The MTA is typically where advanced processing gets done and how integration ...