Virginia Tech runs one of the few production scale IPv6 networks in the United States, with a network of more than 30,000 computing and communication systems. As owners of a system this size and the range of Users involved security is obviously an issue. And, being a university with all sorts of smart people around notably their IT Security Lab and the Bradley Department of Electrical and Computer Engineering they decided to do something about it. The result is MT6D (Moving Target IPv6 Defense (MT6D).