TCP/IP Guide

IPsec General Operation, Components, and Protocols

IPsec isn't the only difficult topic in this book, but it is definitely a subject that baffles many. Most discussions of it jump straight to describing the mechanisms and protocols, without providing a general description of what it does and how the pieces fit together. Well, I recognized that IPsec is important, and I don't shy away from a challenge. Thus, here's my attempt to provide a framework for understanding IPsec's various bits and pieces.

So what exactly does IPsec do, and how does it do it? In general terms, it provides security services at the IP layer for other TCP/IP protocols and applications to use. What this means is that IPsec provides the tools that devices on a TCP/IP network ...