: The Address Resolution Protocol (ARP) has proven to work well under regular circumstances, but it was not designed to cope with malicious hosts. By performing ARP spoofing attacks, a malicious host can either impersonate another host (Man-in-the-Middle attack (MiM)) and gain access to sensitive information, or perform Denial of Service attack (DoS) on target hosts. Several security solutions, such as highly-cost LAN switches and intrusion detection or prevention systems (IDS/IPS), are currently used to detect and prevent these attacks. In this paper, we evaluate, through extensive practical experiments, how effective these security solutions are in detecting ARP spoofing. We clearly show that ARP spoofing has not been given enough attention by most common security solutions which lack efficient detection and prevention mechanisms. We then propose an optimal algorithm that is capable of detecting all various ARP spoofing attacks; especially those not detected using the current mechani...