After you have read this session 1 Introduction, your task is to identify various fundamental concepts of network security. These concepts provide a framework for discussing security and addressing security issues in an enterprise or in cyber space in an organized manner. But for these “big” concepts, our discipline will be a hodgepodge of ideas and ad hoc solutions.  The concepts we discussed include: various dimensions to security,  typical attacks and how they affect the various dimensions to security, 3Ds of security, security policies, mechanisms and services, layering and defense in depth, strategic vs. tactical aspects of security.