Leo and I discuss the design, operation, and complete lack of security of Ethernet - the LAN technology that virtually all of the world uses. We explain how this lack of security enables a wide range of serious attacks to be perpetrated by any other machine sharing the same Ethernet - such as in a wireless hotspot, within a corporate network, or even in a wired hotel where the entire hotel is one big exploitable Ethernet LAN. GRC's ARP Cache Poisoning page contains a detailed explanation of these problems with diagrams and links to readily available Ethernet ARP exploitation malware.ARP Cache Poisoning: /nat/arp.htm