Why do we need ARP?

In the previous chapters, we mentioned what an address resolution protocol is. In this chapter, we will look at it in more depth. In the local network, communication takes place between devices using MAC addresses instead of IP addresses. These are also called link layer addresses. ARP is a request response protocol, which means that one device requests a service and the other one replies in response to that request. Suppose that two devices are present in a network with no external internet connectivity. For them to communicate with each other, they need to rely on a underlying protocol, which is known as the layer 2 protocol. We've already briefly learned about ARP tables. By using an ARP table, a device can maintain a list of all active devices on the network by using a mapping of their IP and MAC addresses. This ARP table technique is quite old and was designed without security considerations in mind. It has some inherent weaknesses that can be exploited...