When Ethernet devices use ARP, it is within a set of rules and conditions. However, just because these rules exist does not mean they need to be followed. Thus, ARP can be abused and twisted to turn it into a hacker's tool. This section studies how ARP weaknesses can be, and are, exploited.
The first thing that needs to be understood is that ARP is NECESSARY for your network to work properly. In other words, if you or a hacker starts altering ARP tables incorrectly, the whole network could be taken offline. As we explain ARP hacking techniques, this message will be repeated several times. By the end of this article, you will understand why and how ARP works, and what damage it can do to a network.