What Is a Messaging System?

A good email system architecture quickly delivers email with embedded sound, graphics, video files, and HTML forms, while providing for future upgrade and scalability. At a simplistic level, the Messaging Server architecture should:

• Accept incoming mail from external sites

• Determine the user mailbox to deliver these messages to and route them accordingly

• Accept incoming mail from internal hosts

• Determine the destination system to deliver these messages to and route them accordingly

Central to an email system architecture is the messaging server itself, a collection of components used to send and deliver messages. In addition to components provided in Messaging Server, the email system also requires an LDAP server and a DNS server. The DNS server must be in place before deploying your email system.

Several factors other than efficiency and scalability influence the Messaging Server architecture. Specifically these are:

• Load balancing

• Firewalls

• High availability

See Chapter 11, Developing a Messaging Server Architecture for more information on these topics.