HP-UX System Administrator's Guide: Configuration Management

7 Configuring Mail
Whether you are administering a single system or a workgroup containing many
systems, you will probably want your users to be able to communicate with each other
using electronic mail (e-mail). This topic area will help you understand what is involved
in setting up e-mail services for your workgroup.
Components of an Electronic Mail System
To properly configure an electronic mail system, you need to know about the following
components:
• “Mail User Agents” (page 121)
• “Mail Delivery Agents” (page 121)
• “Mail Alias Files” (page 122)
• “The Mail Queue” (page 122)
• “Networking Topographies” (page 123)
• “MIME Applications” (page 125)
Mail User Agents
Mail User Agents are the programs that users run to send, and read e-mail. Mail User
Agents that are shipped with HP-UX include dtmail, elm, mail, and mailx. Mozilla
Thunderbird can be downloaded from the HP web site at http://www.hp.com . There
are also commercially available Mail User Agents.
Although Mail User Agents appear to do all the work of transmitting and receiving
e-mail, they are merely the visible part of the entire electronic mail system. Mail User
Agents do not actually deliver the e-mail. Electronic mail delivery is handled by Mail
Delivery Agents.
Mail User Agents:
• Format outgoing messages with proper header information and (if necessary)
encode the outgoing messages for use by Mail Delivery Agents in routing the
messages.
• Allow users to read, save, and delete incoming electronic mail messages.
• Schedule MIME Applications (if necessary) to allow the user to experience
nontextual information attached to incoming electronic mail; for example, viewing
graphics files or video clips, or listening to audio data.
Mail Delivery Agents
Mail Delivery Agents form the core of the electronic mail system. These programs,
usually running in the background, are responsible for routing, and delivering electronic
Components of an Electronic Mail System 121