A lot of arp spoof/poisoning virus are spread nowadays by malicious sites. The infected machines in the local network will send all their neighbors with faked packets and tamper your machine's arptable and pretend to be the real gateway. At the same time, they will cheat the gateway and pretend to be your machine. By this way, all your network traffic is hijacked by the middle-man virus machine.
This Perl script will monitor the gateway's mac address in arptable of the local computer. If it is different from the default value (set in $gatewaymac, gatewayip), the script will alarm and change the adapter to a new IP and MAC address automatically from a predefined list.
This script runs under windows and it requires the "macshift" (a simple windows MAC address changing utility, free, open-source) developed by Nathan True.
