Abstract: Security is at the forefront of most networks, and many companies implement a comprehensive security policy encompassing many of the OSI layers, from application layer all the way down to IP security. However, one area that is often left untouched is hardening Layer 2 and this can open the network to a variety of attacks and compromises. Address resolution protocol is the mapping of IP address to the MAC address (layer 3 to layer2 mapping). ARP provides no authentication mechanism to the incoming request packets this is the reason that any client can forge an ARP message contains malicious information to poison the ARP cache of target host. There are many possible attacks on ARP which can make the communication unsecure such as man-in-the-middle (MITM), Denial of service (DOS), cloning attack, session hijacking and many more attacks.