(.mil/.gov ONLY) Attacks on DoD systems have expanded from simple wiretaps and viruses to session hijacks and trojan horses, and the types and sophistication of these attacks are constantly evolving. In response to these threats, DoD response has also evolved. In recognition of the growing threat and complexity of this problem, DoD developed the defense in depth strategy to protect its networks and information systems. This report describes the impact of evolving technology on the defense in depth strategy. The execution of the strategy requires a significant number of different security and networking technologies. This report focuses on examining the trends and giving an overview of the relevant technologies. This report reviews the defense in depth strategy and discusses its implementation in the Defense Information Infrastructure (DII). Key elements of the strategy and current implementation of the strategy are discussed. How to Obtain a Hardcopy: Contact the CSIAC at email@example.com. How to Obtain a PDF: The PDF for this document is currently not available online. Please contact the CSIAC firstname.lastname@example.org.