What is ARP or Address Resolution Protocol in computer networks, why ARP is used and how ARP works? Explained in detail. ARP is used to resolve IP address to the Ethernet Address. When the ARP table or ARP Cache is missing any required IP-to-Ethernet address translation, the IP packet is queued. Address Resolution Protocol runs and quickly fills the needed IP-to-Ethernet address translation in the ARP table. The updated entry is then used to create an Ethernet frame and transmit the queued IP packet. Notes : Facebook : ARP request is broadcast while ARP reply is unicast. Address resolution protocol operates within the subnet. The target protocol address is necessary in the request packet because it tells the host whether or not to send a reply. he sender hardware address and sender protocol address are mandatory fields because they are going to be updated on the ARP table. We can see the computer’s ARP table/ARP cache using CMD command arp -a. Static ones are the entries maintained manually. On the other hand, dynamic ones are learned by the computer itself. In our case, the new entry updated is the dynamic one. The new entries remain for about 20 minutes in the ARP table. #TechTerms Must learn: DHCP Protocol : ARP Protocol : DNS Explained : OSI Model : IP Address : NIC : Network Protocol : Network Topology: Network Router : Network devices : Firewall : Firewall types : Firewall vs : Firewall working : Firewall limits : Domain name : LAN cable : Hostname :