Now that the Internet has blossomed into the "Information Superhighway" with its traffic and drivers becoming increasingly diverse, security has emerged as a primary concern. This book offers the reader a global, integrated approach to providing internet security at the network layer. The author gives a detailed presentation of the revolutionary IPsec technology used today to create Virtual Private Networks and, in the near future, to protect the infrastructure of the Internet itself. The book addresses IPsec's major aspects and components to help the reader evaluate and compare features of different implementations. It provides a detailed understanding of this cutting-edge technology from the inside, which enables the reader to more effectively troubleshoot problems with specific products. Based on standards documents, discussion list archives, and practitioners' lore, this resource collects all the current knowledge of IPsec and describes it in a literate, clear manner.