This presentation looks at computer network defense and the legal cases of the last year that affect internet and computer security. This presentation clearly and simply explains (in non-legal terms) the legal foundations available to users and service providers to defend their networks. Quickly tracing the legal origins from early property common-law doctrine into today's statutes and then moving into recent court cases and battles. We will look at the past criminal prosecutions and precedents, both civil and criminal, since we last met a year ago. As always, this presentation will quickly become an open forum for questions and debate.