Unix was developed concurrently with the network that would eventually become the Internet. TCP/IP was developed as the language of the Internet. As a Unix clone, Linux is well suited to communicating on the Internet.
A network includes two or more computers set up to communicate with each other. While a LAN connects computers that are physically close to each other, WANs connect two or more geographically distant LANs. The largest WAN is the Internet. LANs are generally faster than WANs due to cost. In either case, you need to configure FQDNs, hostnames, IP addresses, and hardware addresses to communicate on any network.
Network languages such as TCP/IP are also known as protocol stacks. Major protocol stacks such as NetBEUI and IPX/SPX include dozens of different protocols. Protocols are commonly classified in one of the seven levels associated with the OSI model of networking.
Because TCP/IP is the language of the Internet, it is the dominant network protocol suite. The TCP/IP model of networking includes four levels, which are better suited to describe the functionality of different TCP/IP protocols and services such as FTP, HTTP, SNMP, TCP, UDP, IP, Ethernet, and ATM. Other key TCP/IP network services include DNS, DHCP, and ARP.
Every computer that communicates on a TCP/IP network needs an IP address. The standard IP address system is IPv4. There are five IPv4 address classes. Since there aren t enough IPv4 addresses, we re currently in transition to IPv6. Nevertheless, IPv4 addresses are still in common use, especially since there is an IPv6 address available for every IPv4 address.
In the next chapter , you ll put these TCP/IP protocols and IP addresses to good use as you configure your computer and network. You ll also learn to connect your Linux LAN to the Internet.