This chapter presents some basic concepts for the design, implementation, and management of a network-based enterprise boundary protection mechanism. The reader should not expect to see a complete security solution from the material presented in this chapter. The concepts presented here must be combined with host and application security mechanisms, as well as procedural and administrative mechanisms. The chapter will provide an explanation of some of the security concepts involved before explaining how an information protection network (IPN) enables collaboration and information exchange between the enterprise and external entities on the public Internet. Finally, specific technologies needed to implement an IPN will be discussed.