Configuring Networking

If you are connecting your computer to an Ethernet LAN that has a DHCP server available, you probably don’t need to do anything to start up automatically on your LAN and even be connected to the Internet. However, if there is no DHCP server on your LAN and you have to configure your TCP/IP connection manually, here is the information you will probably be prompted for during Linux installation: IP address—If you set your own IP address, this is the our-part, dot-separated number that represents your computer to the network. It would take more than a few sentences to explain how IP addresses are formed and how you choose them (see Chapter 5 for a more complete description). An example of a private IP address is 192.168.0.1.

Netmask—The netmask is used to determine what part of an IP address represents the
network and what part represents a particular host computer. An example of a netmask
for a Class C network is 255.255.255.0. If you apply this netmask to an IP address of
192.168.0.1, for example, the network address would be 192.168.0 and the host address
1. Because 0 and 255 can’t be assigned to a particular host, that leaves valid host numbers
between 1 and 254 available for this local network.
Activate on boot—Some Linux install procedures ask you to indicate if you want the
network to start at boot time (you probably do if you have a LAN).
Set the host name—This is the name identifying your computer within your domain.
For example, if your computer were named “baskets” in the handsonhistory.com
domain, your full host name may be baskets.handsonhistory.com. You can either
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Part III Choosing and Installing a Linux Distribution
set the domain name yourself (manually) or have it assigned automatically, if that information
is being assigned by a DHCP server (automatically via DHCP).
Gateway—This is the IP number of the computer that acts as a gateway to networks
outside your LAN. This typically represents a host computer or router that routes packets
between your LAN and the Internet.
Primary DNS—This is the IP address of the host that translates computer names you
request into IP addresses. It is referred to as a Domain Name System (DNS) server. You
may also have Secondary and Tertiary name servers in case the first one can’t be reached.
(Most ISPs will give you two DNS server addresses.)