Configuring and Activating Network Cards

---

In addition to adding users and groups, it is likely that you will need to activate, configure, and manage your network cards. A lot of this can be done by giving the ifconfig command, previously introduced, a more thorough examination. There are several flags that you can pass to ifconfig that alter the behavior of the network interface card. The most commonly used flags are discussed in Table 19.2.

Table 19.2: ifconfig Flags

Flag	Purpose
-a	This flag is used to display all the information about your IP addresses, including the loopback address.
add <address>	This allows you to add additional IP addresses to your card. The syntax is ipconfig add 10.10.10.55.
delete <address>	This does just the opposite of the add command. It deletes one of the addresses you have added. An example is ipconfig delete 10.10.10.55.
up	This command turns the network card on. An example is ifconfig -up.
down	This command, as you might guess, turns a network card off. An example is ifconfig -down.

As with all shell commands, there are plenty of flags you can pass to ifconfig to make it work in the manner you require. However, the commands listed in Table 19.2 are the essential flags for ifconfig that you must know. Combining a thorough knowledge of ifconfig with who, ping, whois, finger, and traceroute will enable you to do basic network operations and troubleshooting from the shell.

---