Installing and Administering PPP

Chapter 1 17

Introduction

Product Overview

Terrain, distance, and property rights often limit LAN cabling. Where

coax is restricted, network connections can be made by serial lines. Serial

lines are relatively inexpensive and easy to install. However, you need

special software, such as PPP, to run TCP/IP applications over a serial

line.

Properly installed and conﬁgured, PPP and the HP-UX system’s serial

port connections allow you to transmit data to remote locations through

a modem or null-modem cable. (HP-UX systems are equipped with

internal modems, although you can use a cable to connect an external

modem or other system to a serial port.)

PPP provides an easy and ﬂexible means of creating wide-area

TCP/IP-based networks for transfering data among UNIX systems, and

between UNIX systems and other systems that implement the PPP or

SLIP protocols. You can use PPP to connect HP-UX systems to

established TCP/IP networks. You can also use PPP to connect your

HP-UX systems to a hub; this allows the HP-UX systems transparent,

dial-in access to the hub and other LAN-connected hosts. Because of the

transparency of TCP/IP internetwork routing, users may be unaware

that remote facilities are not directly connected to the local network.

PPP includes a command program ( named pppd), a startup script, and a

number of sample conﬁguration ﬁles. You can use PPP to:

• Dial-in to HP 9000 serial IP lines.

• Dial-out from HP 9000 serial IP lines.

• Direct connect to HP 9000 serial IP lines.

Dialing In to an HP 9000

Users at remote supported terminals or PCs can establish dial-in IP

connections with logins. For a login connection, the user establishes a

modem link to an HP 9000 and logs in as usual. After login, the Login

shell script is run. The script starts pppd on the local system which will

communicate with the pppd on the peer. The two pppd’s will negotiate

and establish a PPP connection.