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ARP Protocol
The Address Resolution Protocol (ARP) is a communication protocol used for discovering the link layer address, such as a MAC address, associated with a given internet layer address, typically an IPv4 address. This mapping is necessary because the data link and network layer addresses of a device can be different, and ARP provides a way to translate between them.
ARP operates within the Internet Protocol Suite's networking layer, and is used by network devices to map an IP address to a physical address, such as an Ethernet address. ARP is used for communication within a network segment (layer 2), while the Internet Protocol is used for communication across network segments (layer 3).
ARP is a stateless protocol, meaning that each request is independent of the previous request in the same session. ARP is also a broadcast protocol, meaning that it is used for one-to-all communication within a network.
ARP Request
An ARP request is a message that is sent by a device to all other devices in a network to request their MAC addresses. The ARP request contains the IP address of the device that sent the request, and the MAC address of the device that is requesting the IP address. The ARP request is broadcast to all devices in the network, and the device that has the requested IP address responds with an ARP reply.
ARP Reply
An ARP reply is a message that is sent by a device to another device in a network to provide its MAC address. The ARP reply contains the IP address of the device that sent the request, and the MAC address of the device that is requesting the IP address. The ARP reply is sent directly to the device that sent the ARP request.
ARP Table
An ARP table is a table that is used by a device to store the IP addresses and MAC addresses of other devices in a network. The ARP table is used by the device to determine the MAC address of a device when it receives an ARP request from that device.