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 “MTA and MUAs Supported on HP-UX 11i v2” lists the MTA and
MUAs that HP-UX 11i v2 supports.
Table 1-1 MTA and MUAs Supported on HP-UX 11i v2
MTA/MUA | Description |
|---|
| elm | 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. |
| mail/rmail | mail/rmail is a customized HP program used to send remote
or local mail. It is primarily used by Sendmail for local mail delivery. |
| mailx | mailx is an interactive message processing system that
provides a comfortable and flexible environment for sending and
receiving messages electronically. |
| Sendmail | Sendmail sends a message to one or more recipients or addresses,
routing the message over appropriate networks. |
This chapter discusses the following topics:
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|
 | CAUTION: Do not use two separate mail programs simultaneously
to access the same mail file. This may cause unpredictable results. |
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