mail_intro(7) Miscellaneous Information Manual mail_intro(7)
mail_intro - Introductory information on the Tru64 UNIX mail system
The Tru64 UNIX mail system enables you to exchange mail with other users on your system, as well as with other systems connected to your
local network and with users on other networks (provided your system and network are connected to other networks).
Mail System Concepts
Mail systems consist of the following components: User agent - The user agent provides the interface through which you interact with the
mail system. Generally, the user interface enables you to create, send, receive, read, save, and manage your mail messages.
Tru64 UNIX provides the following user agents: CDE's Mailer - For further information, see the Common Desktop Environment: User's
Guide . Mail or mailx - For further information, see the Command and Shell User's Guide . The Rand Message Handling program (MH) -
For further information, see the mh(1) and xmh(1X) reference pages. Transport agent - The transport agent provides an interface
between the user agents and the delivery agents. The sendmail command is a transfer agent. Delivery agent - The delivery agent
provides the mechanism for delivering the mail messages to end users, systems, and networks. The binmail and deliver commands are
delivery agents for standard mail and IMAP mail, respectively.
In Tru64 UNIX, the sendmail program acts as both the transport and delivery agent. It does so by implementing the Simple Mail Transfer Pro-
tocol (SMTP), which is the specification for the Internet's delivery agent.
Initially standards did not exist for mail addresses and computer networks. Many different address formats and network protocols exist.
Mail programs must interact with different network protocols, as well as recognize and reformat different mail address formats. Fortu-
nately, these difficulties were recognized and standards, such as the Standard for the Format of ARPA Internet Text Messages (RFC 822) and
The Domain Naming Convention for Internet User Applications (RFC 819), emerged. A mail program still must recognize addresses in various
formats and communicate with different network protocols. The sendmail program addresses these issues through the use of the sendmail.cf
The Sendmail Configuration File
The sendmail.cf configuration file provides the sendmail program with the information to perform the following tasks: Choose delivery
agents Use address rewriting rules Define mail header information Perform some routing
When it starts, the sendmail program reads the sendmail.cf configuration file. The information in the sendmail.cf configuration file
enables sendmail to rewrite the addresses of mail it receives into the address form expected by the mail delivery agent. It also enables
sendmail to set parameters and arguments to the mail delivery program.
The configuration file contains information that is used for the following functions: Define message precedence for mail delivery Define
administrative IDs to override the sender's address Define message headings Define the mail program to use Set options used by the sendmail
The default Tru64 UNIX configuration file (located in /var/adm/sendmail/sendmail.cf) is adequate for most standalone systems. However, if
you plan to connect your system to a network, you will have to modify the sendmail.cf file.
Tru64 UNIX provides the mailconfig and mailsetup utilities, which you can use to create mail configuration files. If you prefer to manipu-
late the configuration file manually, you should use the m4 macros provided for this purpose. (See the sendmail.m4 reference page.)
For more information on configuring mail, see the Network Administration manual.
Commands: binmail(1), mailconfig(8), mailsetup(8), mailx(1), sendmail(8), sendmail.m4(8)
Standard for the Format of ARPA Internet Text Messages (RFC 822)
The Domain Naming Convention for Internet User Applications (RFC 819)
UNIX System Administration Handbook, Englewood Cliffs, N.J.: Prentice Hall, Inc., 1989. delim off