View Source: ARP - Waikato Linux Users Group

Edit PageHistory Diff Info LikePages

An [Acronym] for __A__ddress __R__esolution __P__rotocol.

A protocol that enables a [IP] conversation to occur over an [Ethernet] network. [IP] (version 4) uses 32-bit addresses, usually displayed in a dotted quad format, <tt>nnn.nnn.nnn.nnn</tt>. [Ethernet] uses 48-bit addresses, known as [MAC] addresses, usually displayed as a 17-character colon-delimited hex string, <tt>nn:nn:nn:nn:nn:nn</tt>. (A real example: my workstation has the IP address <tt>192.168.1.46</tt> and a MAC address of <tt>00:50:FC:B1:21:C7</tt>)

In order to send an [IP] packet over [Ethernet], your computer needs to associate a [MAC] address with the requested [IP] address. It does this by sending an [Ethernet] Broadcast packet, using the [ARP] protocol. This packet basically says "What [MAC] address is associated with this [IP] address?", sometimes referred to as a "who-has?" request.

Although any workstation on the local [Ethernet] is capable of sending a response, usually it is only the actual workstation you wish to communicate with that bothers to reply, providing both its [IP] address and its [MAC] address.

To issue a gratuatis [ARP] to flush an [ARP] cache use arping(8).

----
CategoryProtocols

2 pages link to ARP:

Last edited on Thursday, September 23, 2004 6:52:26 pm by AristotlePagaltzis

Edit PageHistory Diff Info LikePages