Part 3

Host Name
The host name is the name of the local machine, combined with the name of
your organization. Many organizations let users choose the host names for
their machines. Programs such assendmail andrlogin use host names to specify remote machines on a network. System Administration Guide, Volume I
contains more information about host names.

IP Address
The IP address is one of the two types of addresses each machine has on a TCP/IP network that identifies the machine to its peers on the network. This address also gives peer hosts a notion of where a particular host is located on the network. If you have installed the Solaris operating environment on a machine on a network, you may recall specifying the IP address during the
installation process. IP addressing is a significant aspect of TCP/IP and is explained fully in ”Designing Your IP Addressing Scheme” on page 33.

Hardware Address
Each host on a network has a hardware address, which also identifies it to its peers. This address is physically assigned to the machine’s CPU or network interface by the manufacturer. Each hardware address is unique.

Reaching Beyond the Local-Area Network—the Wide-Area Network
As your network continues to function successfully, users may need to access information available from other companies, institutes of higher learning, and
other organizations not on your LAN. To obtain this information, they may need to communicate over a wide-area network (WAN), a network that covers a
potentially vast geographic area and uses network media such as leased data or telephone lines, X.25, and ISDN services.

A prime example of a WAN is the Internet, the global public network that is the successor to the WANs for which TCP/IP was originally developed. Other examples of WANs are enterprise networks, linking the separate offices of a single corporation into one network spanning an entire country, or perhaps an entire continent. It is entirely possible for your organization to construct its own WAN.

To interconnect your TCP/IP network with other networks, you must obtain a unique IP network number. At the time of this writing, IP network numbers
are assigned by an organization known as the InterNIC.
If hosts on your network are going to participate in the Internet Domain Name system (DNS), you must obtain and register a unique domain name. The InterNIC also handles the registration of domain names under certain top-level domains such as .com (commercial), .edu (education), and .gov (government).
Chapter 3, “Planning Your Network,” contains more information about the InterNIC. (For more information on DNS, refer to NIS+ and FNS Administration Guide.)