The main function of the arp protocol is to resolve IP addresses into physical addresses. ARP refers to the Address Resolution Protocol, which is a TCP/IP protocol that obtains a physical address based on an IP address. Using the ARP protocol, the target hardware address (MAC address) information can be parsed based on the IP address information in the network layer IP packet header to ensure Smooth communication.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
The main function of the ARP protocol is to resolve IP addresses into physical addresses.
What is arp protocol?
Address Resolution Protocol, or ARP (Address Resolution Protocol), is a TCP/IP protocol that obtains a physical address based on an IP address. When the host sends information, it 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 physical address are stored in the local machine. The ARP cache is kept for a certain period of time, and the ARP cache is directly queried on the next request to save resources.
The address resolution protocol is based on mutual trust between hosts in the network. Hosts on the local area network can send ARP response messages independently, and other hosts will not detect the message when they receive the response message. The authenticity will be recorded in the local ARP cache; thus the attacker can send a fake ARP reply message to a certain host, so that the information sent cannot reach the expected host or reaches the wrong host, which constitutes An ARP spoof.
The ARP command can be used to query the correspondence between IP addresses and MAC addresses in the local ARP cache, add or delete static correspondence, etc. Relevant protocols include RARP and proxy ARP. NDP is used to replace Address Resolution Protocol in IPv6.
Function:
The OSI model divides network work into seven layers. The IP address is on the third layer of the OSI model and the MAC address is on the second layer. They are not directly connected to each other. deal with. When sending IP data packets through Ethernet, it is necessary to encapsulate the headers of the third layer (32-bit IP address) and the second layer (48-bit MAC address). However, since only the target IP address is known when sending, its MAC address is not known. , and cannot span the second and third layers, so the address resolution protocol needs to be used. Using the address resolution protocol, the target hardware address (MAC address) information can be parsed out based on the IP address information in the network layer IP packet header to ensure smooth communication.
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