DHCP: What Is It?

This article provides some basic information about Dynamic Host Configuration Protocol (DHCP) and how it relates to the AirPort Base Station.
DHCP (Dynamic Host Configuration Protocol) is a protocol that lets network administrators centrally manage and automate the assignment of Internet Protocol (IP) addresses. Its purpose is to enable individual computers on an IP network to obtain their configurations from the DHCP server or servers, in particular, servers that have no exact information about the individual computers until they request the information. This can be used in a LAN environment or by an ISP.

The ability to do this reduces the work necessary to administer a large IP network. Without DHCP, the IP address must be entered manually at each computer, and if computers move to another location in another part of the network, a new IP address must be entered. DHCP lets a network administrator supervise and distribute IP addresses from a central point and automatically sends a new IP address when a computer is connected in a different place in the network, or reconnects to an ISP.

The following definitions will be helpful when setting up the AirPort Base Station for use with your Internet Service Provider:

What is an IP address?

An IP address (also called an IP number) is a number (typically written as four numbers separated by periods, for example 107.4.1.3 or 84.2.1.111) which uniquely identifies a computer that is making use of the Internet. It is analogous to your telephone number in that the telephone number is used by the telephone network to direct calls to you. The IP address is used by the Internet to direct data to your computer such as the data your Web browser retrieves and displays when you surf the Internet. One task of DHCP is to assist in the problem of getting a functional and unique IP number into the hands of the computers that make use of the Internet.

What is a MAC address?

A MAC address (also called an Ethernet address or an IEEE MAC address) is a number that uniquely identifies a computer that has an Ethernet interface. It is typically written as twelve hexadecimal digits, 0 through 9 and A through F, or as six hexadecimal numbers separated by periods or colons, for example, "0080002012ef" or "00:80:0:2:20:ef". Unlike the IP number, it includes no indication of where your computer is physically located. In DHCP's typical use, the server uses a requesting computer's MAC address to uniquely identify it.

What is a DHCP lease?

A DHCP lease is the amount of time that the DHCP server grants to the DHCP client permission to use a particular IP address. A typical server allows its administrator to set the lease time.

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Published Date: Feb 20, 2012