HP-UX Mailing Services Administrator's Guide (B2355-91064)

1 Mailing Services Overview

Mailers are a set of UNIX® commands that provide command-line interfaces for users

to send and receive messages over the network. These interfaces, which are generally

referred to as Mail User Agents (MUA), communicate with a Mail Transport Agent

(MTA) to send mail messages to the appropriate destination, and receive messages

destined to the end user’s mailbox.

An MUA is a program that allows users to compose and read electronic mail messages.

The MUA provides an interface between the user and the MTA. An outgoing mail is

eventually delivered to an MTA for delivery, and the incoming messages are collected

from the MTA.

An MTA is a program that is responsible for delivering electronic mail messages. Upon

receiving a message from an MUA or another MTA, an MTA stores the message locally,

analyzes the recipients, and either delivers the message (for local addresses) or forwards

the message to another MTA for routing. In either case, the MTA can edit and add to

the message headers.

HP-UX systems use the Sendmail MTA and the elm, mail, and mailx MUAs.

Table 1-1 lists the MTA and MUAs that HP-UX 11i v2 and HP-UX 11i v3 supports.

Table 1-1 MTA and MUAs Supported on HP-UX 11i v2 and HP-UX 11i v3

DescriptionMTA/MUA

elm is the electronic mail processing system for UNIX. It is designed as an MUA

to run with Sendmail to send or receive messages. The most significant difference

between elm and other mail systems is that it is screen-oriented.

elm

mail/rmail is a customized HP program used to send remote or local mail. It is

primarily used by Sendmail for local mail delivery.

mail/rmail

mailx is an interactive message processing system that provides a comfortable

and flexible environment for sending and receiving messages electronically.

mailx

Sendmail sends a message to one or more recipients or addresses, routing the

message over appropriate networks.

Sendmail

This chapter discusses the following topics:

• elm

• mailx

• mail/rmail

• sendmail