If you've ever wondered how Linux carries out the complicated tasks assigned to it by the IP protocols -- or if you just want to learn about modern networking through real-life examples -- Understanding Linux Network Internals is for you.
Like the popular O'Reilly book, Understanding the Linux Kernel, this book clearly explains the underlying concepts and teaches you how to follow the actual C code that implements it. Although some background in the TCP/IP protocols is helpful, you can learn a great deal from this text about the protocols themselves and their uses. And if you already have a base knowledge of C, you can use the book's code walkthroughs to figure out exactly what this sophisticated part of the Linux kernel is doing.