Address Resolution Protocol

What Does Address Resolution Protocol Mean?

Address Resolution Protocol (ARP) is a low-level network protocol for translating network layer addresses into link layer addresses.


ARP lies between layers 2 and 3 of the OSI model, although ARP was not included in the OSI framework and allows computers to introduce each other across a network prior to communication.

Because protocols are basic network communication units, address resolution is dependent on protocols such as ARP, which is the only reliable method of handling required tasks.

Techopedia Explains Address Resolution Protocol

When configuring a new network computer, each system is assigned an Internet Protocol (IP) address for primary identification and communication. A computer also has a unique media access control (MAC) address identity. Manufacturers embed the MAC address in the local area network (LAN) card. The MAC address is also known as the computer’s physical address.

Before two computers communicate, each must know the other’s relative IP or MAC addresses. If computer A only has computer B’s MAC address, computer A can reveal its IP address by sending an ARP request to computer B. Computer B may then reply by attaching its IP address with ARP to computer A. This simple address translation and exchange process is the primary role of ARP.

ARP tables can be stored to increase transmission rates by keeping track of addresses known to the network and transmitting any MAC or IP address changes via ARP.

There is no authentication required at this level, so spoofing of IP and MAC addresses is possible. Additional software may be required to police the ARP tables and prevent malicious user attacks.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…