LPI Linux Certification in a Nutshell, 2nd Edition

Objective 3: TCP/IP Configuration and Troubleshooting

Linux distributions offer various automation and startup techniques for networks, but most of the essential commands and concepts are not distribution-dependent. The exam tests fundamental concepts and their relationships to one another as well as to system problems. This Objective covers the configuration of TCP/IP on common network interfaces such as Ethernet.

Network Interfaces

A computer must contain at least one network interface to be considered part of a network. The network interface provides a communications link between the computer and external network hardware. This could mean typical network adapters such as Ethernet or Token Ring, PPP dial-up connections, parallel ports, wireless, or other networking forms.

Configuration files

The following files contain important information about your system's network configuration:

/etc/hosts

This file contains simple mappings between IP addresses and names and is used for name resolution. For very small private networks, /etc/hosts may be sufficient for basic name resolution. For example, this file associates the local address 192.168.1.30 with the system smp and also with smp.mydomain.com:

127.0.0.1       localhost       localhost.localdomain
192.168.1.1     gate
192.168.1.30    smp smp.mydomain.com

/etc/nsswitch.conf

This file controls the sources used by various system library lookup functions, such as name resolution. It allows the administrator to configure the use of traditional local files ...