What is the protocol used to resolve mac addresses

The protocol used to resolve mac addresses is "RARP". RARP (Reverse Address Translation Protocol) can resolve MAC addresses into IP addresses, allowing physical machines on the LAN to request their IP addresses from the gateway server's ARP table or cache. RARP issues a physical address to be reverse-resolved and expects its corresponding IP address to be returned. The response includes the IP address issued by a RARP server that can provide the required information.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

The protocol used to resolve mac addresses is "RARP", which can resolve MAC addresses into IP addresses.

The relationship between IP address and MAC address is ARP, and the conversion from MAC to IP address is RARP.

Reverse Address Translation Protocol (RARP: Reverse Address Resolution Protocol) allows physical machines on the LAN to request their IP addresses from the gateway server's ARP table or cache. The network administrator creates a table in the LAN gateway router to map physical addresses (MAC) and their corresponding IP addresses. When setting up a new machine, its RARP client program needs to request the appropriate IP address from the RARP server on the router. Assuming a record has been set up in the routing table, the RARP server will return the IP address to the machine, which will store it for later use. RARP can be used on Ethernet, optical fiber distributed data interface and token ring LAN

The reason why RARP occurs

ARP (Address Resolution Protocol) is the device that knows the IP address to obtain a physical address that you don't know. Suppose a device does not know its own IP address, but does know its physical address. This is the case with diskless workstations on the network. All the device knows is the physical address on the network interface card. What should you do in this situation? RARP (Reverse Address Resolution Protocol) is a protocol for this situation.

RARP works in the opposite way to ARP. RARP issues a physical address to be reverse-resolved and expects its corresponding IP address to be returned. The response includes the IP address issued by a RARP server that can provide the required information. Although the sender sends a broadcast message, RARP stipulates that only the RARP server can generate a response. Many networks specify multiple RARP servers, both for load balancing and as a backup in case of problems.

Working principle

• The sending host sends a local RARP broadcast. In this broadcast packet, it declares its MAC address and requests any recipients. The RARP server that receives this request allocates an IP address;

• After the RARP server on the local network segment receives this request, it checks its RARP list to find the IP address corresponding to the MAC address;

• If it exists, the RARP server will send a response packet to the source host and provide this IP address to the other host for use;

• If does not exist, the RARP server does not respond to this;

• The source host receives the response information from the RARP server and uses the obtained IP address for communication; if it has not been received The response information from the RARP server indicates that the initialization failed.

The working process of RARP:

1. Each device on the network will have a unique hardware address, usually determined by the device Manufacturer-assigned MAC address. PC1 reads the MAC address from the network card, and then sends a RARP request broadcast packet on the network, requesting the RARP server to reply to the PC's IP address.

2. The RARP server receives the RARP request packet, assigns it an IP address, and sends the RARP response to PC1.

#3. After PC1 receives the RARP response, it uses the obtained IP address for communication.

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