ARP, RARP and GARP, What is it and what do we use it for?
ARP, RARP and GARP are essential networking protocols and something every good network administrator should understand
ARP - ADDRESS RESOLUTION PROTOCOL
ARP is a protocol used to match ip addresses with MAC addresses. It simply works by a router broadcasting an layer 2 ARP packet to all devices. The packet will hold the ip address that it wants to pair with a mac address. When the right client with that ip address recives the packet it forward a packet to the router with its own MAC address, where it confirms the ownership of the ip addres. Once the router recives the answer it will store the information in its ARP table.
ARP requests are only sent if nesecery.
RARP - REVERSE ADDRESS RESOLUTION PROTOCOL
GARP - GRATUITOUS ADDRESS RESOLUTION PROTOCOL
Gratuitous Address Resolution Protocol (GARP) is a specialized type of ARP used for announcement rather than discovery. It enables a device to broadcast its IP and MAC address binding to the entire network. This ensures that all devices on the network have the correct information about the announcing device, which helps to avoid misrouting caused by outdated ARP entries, its often sent if a device changes its ip address.