HOWTO : Protect you from being ARP spoofing
This paper is also valuable to read which is written by the developer of XARP (it will mention below).
ARP security often ignored and nobody cares about lower layer security nowadays. ARP attacks are real threat with high impact.
How can I protect myself from being attacked? Yes, you can. The following tools will alert you when the attack is taking place.
If you are Linux and/or Windows users, you can use XARP – Advanced ARP Spoofing Detection. It works on Ubuntu 12.04 but it does not support Unity which the tray icon will not be shown.
If you are Mac OSX users, you can use ARPGuard.
If you are Android users, you can use DroidSheep Guard.
Or, if you do not want to install the captioned softwares and your router can set static ARP, do it and your subnet is protected upon set.