Installing and Administering PPP

18 Chapter 1
Introduction
Product Overview
For a connection without a login, the user simply dials in to a preset HP
9000 serial line where the serial protocol is already running on the line.
Dialing Out from an HP 9000
HP 9000 users can establish dial-out IP connections with or without
login. This may be to any remote host that runs a supported serial IP
protocol.
For a login connection, the user simply invokes pppd at the HP-UX shell
prompt. pppd establishes a modem link to the specified host and logs in.
pppd runs a command on the remote machine to initiate the specified
serial IP protocol and establish the connection.
For a connection without login, the user’s action is the same. After the
user invokes pppd, a preset line is assigned to that user. The user has
full network access to the remote host.
Direct Connections
You, the system administrator, may set up a direct (hardwired) IP
connection between an HP 9000 and a remote host. In effect, this is
simply a long distance extension of the LAN.
HP-UX PPP Features
PPP on HP-UX offers the following features:
• On demand dial-up connections. PPP can establish an asynchronous
link over standard telephone lines whenever traffic warrants a call.
This is in contrast to network routers that require an expensive
leased line to provide a constant connection. When the traffic has
completed, PPP can hang up the connection to save the telephone
costs. User applications cannot distinguish between an on-demand
dialup link and one that is constantly maintained, except by looking
at the clock.
• Link traffic control. The HP-UX system administrator has complete
control over the traffic that is allowed to traverse the link. PPP can
turn an HP-UX system into a selective-isolation packet filtering
“firewall” gateway, enhancing the security provided to other systems
on the local network.