Obtaining an Internet address / Static assignment of an IP address

Obtaining an Internet address
9.3.1 This page will explain how an Internet address is obtained.


A network host needs to obtain a globally unique address in order to function on the Internet. The physical or MAC address that a host has is only locally significant, identifying the host within the local area network. Since this is a Layer 2 address, the router does not use it to forward outside the LAN.

IP addresses are the most commonly used addresses for Internet communications. This protocol is a hierarchical addressing scheme that allows individual addresses to be associated together and treated as groups. These groups of addresses allow efficient transfer of data across the Internet.

Network administrators use two methods to assign IP addresses. These methods are static and dynamic. Later in this lesson, static addressing and three variations of dynamic addressing will be covered. Regardless of which addressing scheme is chosen, no two interfaces can have the same IP address. Two hosts that have the same IP address could create a conflict that might cause both of the hosts involved not to operate properly. As shown in Figure , the hosts have a physical address by having a network interface card that allows connection to the physical medium.

The next page will focus on static IP address assignments.

Static assignment of an IP address
9.3.2 This page will discuss static assignments.


Static assignment works best on small, infrequently changing networks. The system administrator manually assigns and tracks IP addresses for each computer, printer, or server on the intranet. Good recordkeeping is critical to prevent problems which occur with duplicate IP addresses. This is possible only when there are a small number of devices to track.

Servers should be assigned a static IP address so workstations and other devices will always know how to access needed services. Consider how difficult it would be to phone a business that changed its phone number every day.

Other devices that should be assigned static IP addresses are network printers, application servers, and routers.

The next page will introduce Reverse Address Resolution Protocol (RARP).