The ABC'S of 'Hacking' Part 2

ARP Poisoning Main Issues: The Address Resolution Protocol's uses in detecting and rerouting traffic can cause havoc on a network where ARP's functionality is needed. ARP's capability of altering ARP tables at the switch makes it a prime target for hackers as point of entry in their attack. Because ARP works at both the network layer and the data link layer it can shutdown a network's data transfer with the outside world by confusing computers …

…and the router therefore owning that material. However, potentially dangerous ARP spoofing can be detected using programs like ARPWatch to monitor all ARP/IP address pairing and alert the administrator when changes occur. It listens to the network like a sniffer and compares all captured replies against a database. The solution to avoid ARP attacks is to encrypt all data passing over a network, however the overhead associated with this method would cost too much.