Datasheet
“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 421 — #447
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21
Linux in the Network
Table 21.3: Private IP Address Domains
Network/Netmask Domain
10.0.0.0/255.0.0.0 10.x.x.x
172.16.0.0/255.240.0.0 172.16.x.x – 172.31.x.x
192.168.0.0/255.255.0.0 192.168.x.x
21.1.3 Domain Name System
DNS assists in assigning an IP address to one or more names and assign-
ing a name to an IP address. In Linux, this conversion is usually carried out
by a special type of software known as bind. The machine that takes care
of this conversion is called a name server. The names make up a hierarchi-
cal system in which each name component is separated by dots. The name
hierarchy is, however, independent of the IP address hierarchy described
above.
Consider a complete name, such as laurent.suse.de, written in the for-
mat hostname.domain. A full name, referred to as a fully qualified domain
name (FQDN), consists of a host name and a domain name (suse.de). The
latter also includes the top level domain or TLD (de).
TLD assignment has become quite confusing for historical reasons. Tra-
ditionally, three-letter domain names are used in the USA. In the rest of
the world, the two-letter ISO national codes are the standard. In addition
to that, multiletter TLDs were introduced in 2000 that represent certain
spheres of activity (for example, .info, .name, .museum).
In the early days of the Internet (before 1990), the file /etc/hosts was
used to store the names of all the machines represented over the Internet.
This quickly proved to be impractical in the face of the rapidly growing
number of computers connected to the Internet. For this reason, a decen-
tralized database was developed to store the host names in a widely dis-
tributed manner. This database, similar to the name server, does not have
the data pertaining to all hosts in the Internet readily available, but can dis-
patch requests to other name servers.
The top of the hierarchy is occupied by root name servers. These root name
servers manage the top level domains and are run by the Network In-
formation Center, or NIC. Each root name server knows about the name
servers responsible for a given top level domain. Information about top
level domain NICs is available at http://www.internic.net.
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SUSE LINUX Enterprise Server