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InARP (Inverse Address Resolution Protocol)

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The Inverse Address Resolution Protocol (InARP) is a protocol used in computer networking to map a MAC address to an IP address. InARP is used in situations where a device knows the MAC address of the device it wants to communicate with, but does not know the IP address.

In this article, we will discuss the basics of InARP, its operation, and its benefits.

Basics of Inverse Address Resolution Protocol (InARP)

InARP is an extension of the Address Resolution Protocol (ARP). ARP is used to map a MAC address to an IP address. When a device wants to communicate with another device on a network, it needs to know the MAC address of the device it wants to communicate with. This is because devices on a network communicate using MAC addresses, not IP addresses.

ARP is used to resolve the MAC address of a device based on its IP address. In other words, ARP is used when a device knows the IP address of the device it wants to communicate with, but does not know the MAC address.

However, there are situations where a device knows the MAC address of the device it wants to communicate with, but does not know the IP address. This is where InARP comes in.

InARP is used to resolve the IP address of a device based on its MAC address. In other words, InARP is used when a device knows the MAC address of the device it wants to communicate with, but does not know the IP address.

How Inverse Address Resolution Protocol (InARP) Works

InARP works by sending an InARP request message to the network. The InARP request message contains the MAC address of the device the sender wants to communicate with. The device that receives the InARP request message checks its ARP table to see if it has a matching MAC address. If it does, the device responds to the InARP request message with an ARP reply message that contains the IP address of the device with the matching MAC address.

If the device that receives the InARP request message does not have a matching MAC address in its ARP table, it does not respond to the InARP request message. The sender must then use other methods, such as sending a broadcast message, to find the IP address of the device it wants to communicate with.

Benefits of Inverse Address Resolution Protocol (InARP)

InARP is a useful protocol in situations where a device knows the MAC address of the device it wants to communicate with, but does not know the IP address. This can occur in situations such as:

  • When a device is moved to a new location on the network, and its IP address changes, but its MAC address remains the same.
  • When a device is replaced with a new device that has a different IP address, but the same MAC address.
  • When a device is communicating with a device on a different network, and the IP address of the device on the other network is not known.

In these situations, InARP can be used to quickly and efficiently resolve the IP address of the device the sender wants to communicate with.

Conclusion

The Inverse Address Resolution Protocol (InARP) is a protocol used in computer networking to map a MAC address to an IP address. InARP is used in situations where a device knows the MAC address of the device it wants to communicate with, but does not know the IP address. InARP works by sending an InARP request message to the network, which is then responded to by the device with the matching MAC address in its ARP table. InARP is useful in situations where a device has changed location on the network, or when a device is replaced with a new device that has a different IP address, but the same MAC address.