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This article is to share with you about the functions of arp protocol. The editor thought it was very practical, so I shared it with you as a reference. Let's follow the editor and have a look.

The main function of arp protocol is to resolve IP addresses to physical addresses. Using ARP protocol, the target hardware address (MAC address) information can be parsed according to the IP address information in the IP packet header of the network layer, so as to ensure the smooth communication.

The main function of ARP protocol is to resolve IP addresses to physical addresses.

What is the arp protocol?

Address Resolution Protocol, or ARP (Address Resolution Protocol), is a TCP/IP protocol that obtains physical addresses based on IP addresses. When sending information, the host broadcasts the ARP request containing the target IP address to all hosts on the local area network, and receives the return message to determine the physical address of the target; after receiving the return message, the IP address and the physical address are stored in the local ARP cache and retained for a certain period of time, and the next request directly queries the ARP cache to save resources.

The address resolution protocol is based on the mutual trust of hosts in the network. Hosts on the local network can send ARP reply messages on their own. When other hosts receive the reply message, they will not check the authenticity of the message and will record it in the local ARP cache. As a result, an attacker can send a pseudo ARP reply message to a host, so that the information it sends cannot reach the expected host or the wrong host, which constitutes an ARP spoofing.

The ARP command can be used to query the correspondence between IP address and MAC address in the native ARP cache, add or delete static correspondence, and so on. Related protocols include RARP and proxy ARP. NDP is used to replace the address resolution protocol in IPv6.

Features:

The OSI model divides the network work into seven layers. The IP address is in the third layer of the OSI model, and the MAC address is in the second layer. When sending IP packets over Ethernet, it is necessary to encapsulate the headers of layer 3 (32-bit IP address) and layer 2 (48-bit MAC address). However, because only the destination IP address is known, but not its MAC address, and cannot cross the second and third layers, the address resolution protocol needs to be used. Using the address resolution protocol, the target hardware address (MAC address) information can be parsed according to the IP address information in the IP packet header of the network layer, so as to ensure the smooth communication.

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