HP-UX System Administrator's Guide: Overview

elm
Though not formally supported by HP, you can also use the following commonly used
utilities for reading, composing, and sending electronic mail:
Mozilla
Mozilla is shipped with HP-UX as it is needed as a default browser for
accessing the System Management Homepage. Mozilla includes a built-in
E-mail client.
rmail
If you have installed and use the GNU Emacs editor, you can use its built
in E-mail client, rmail.
Remote Logins / Terminal Emulation
From an HP-UX shell you can log into a remote system using any of the following
protocols if they have been made available to you:
rlogin rlogin, a utility that runs on your local server, communicates with a
daemon called rlogind on the remote server, if it is running, to allow you
to log into the remote server if you have a valid account on that system.
IMPORTANT: The protocol supporting rlogin is not a secure protocol.
Your login information, including passwords and other information you
enter during your login session is sent over the network unencrypted! That
information is at risk of being intercepted and misused.
ssh ssh (Secure Shell) provides much more secure remote logins than does the
rlogin protocol. It authenticates the remote server (and allows the remote
server to authenticate your local server) by using public-key encryption. It
uses encryption in all communications with the remote server during your
login session.
telnet As with rlogin, telnet generally uses unencrypted communications
making your login sessions to remote servers vulnerable to interception. If
you are working on a closed network, among servers and users you trust,
telnet is available on HP-UX for your use. If secure communications
between your local server and the remote server you are trying to login to
are important, use ssh.
File Transfers
There are several protocols available on HP-UX to transfer files between computers.
Depending on the protocol used, files can be transferred between HP-UX based systems,
between an HP-UX based system and a Linux based system, or between an HP-UX
based system and a Microsoft Windows based system. In addition to the following
protocols, applications and custom programs can transfer files using inter process
communication (via system calls):
110 Major Components of HP-UX