Linux in a Nutshell, 6th Edition

Configuring TCP/IP

Certain commands are normally run in the system’s startup files to enable a system to connect to a network. These commands can also be run interactively.

Network interfaces

The network interface represents the way that the networking software uses the hardware: the driver, the IP address, and so forth. To configure a network interface, use the ip command. This command replaces the older ifconfig command. It has a Cisco IOS-like command syntax that will be familiar to many network administrators. With ip, you can assign an address to a network interface, setting the netmask, broadcast address, and IP address at boot time. You can also set network interface parameters, including the use of ARP, the use of driver-dependent debugging code, the use of one-packet mode, and the address of the correspondent on the other end of a point-to-point link. For more information on ip, see Chapter 3.

Serial-line communication

There are two protocols for serial-line communication: Serial Line IP (SLIP) and Point-to-Point Protocol (PPP). These protocols let computers transfer information using the serial port instead of a network card, and a serial cable instead of an Ethernet cable. SLIP is rarely used anymore, having been replaced by PPP.

PPP was intended to remedy some of SLIP’s failings; it can hold packets from -non-Internet protocols, it implements client authorization and error detection/correction, and it dynamically configures each network protocol that passes through it. Under ...