This book starts where most other books stop, providing an under-the-hood detailed presentation of the networking architecture in the Linux kernel. It is probably the only currently available book covering such a topic, and provides insider-level information on the Linux transmission control protocol/Internet protocol (TCP/IP) implementation. This detailed presentation of the Linux networking stack is enlightening reading for those readers and developers interested in extending the networking stack, or in developing advanced network services. A reader, like me, with a moderate to advanced background in networking will surely appreciate the Linux-specific implementation details, while the typical Linux kernel hacker will be able to increase her or his knowledge on TCP/IP. The book succeeds in meeting two goals: presenting an excellent introduction to TCP/IP, and presenting, in a clear and precise manner, complicated kernel-level implementation details.

Although it has several authors, the book preserves the same perfect logical flow, and precise writing style, throughout the more than 20 chapters. The academic background of the authors makes for a well-structured document, with pertinent references, and an overall excellent coherence. The important kernel data structures and architectural building blocks are abundantly illustrated, ensuring easy reading and understanding.

The book is a translation from a German version (published in 2002), so only the 2.4 (and below) version of the Linux kernel is covered. For those readers interested in the most recent kernel version (2.6), the book provides the necessary knowledge required for beginning self-exploration, and do-it-yourself kernel hacking.

I read this book with extreme interest. The first chapters present the background on the Linux kernel architecture. This material is required for understanding the rest of the book. These chapters cover the kernel structure, and have a strong focus on the packet-related data structures, and their relationships with network devices. The next six chapters describe the implementation of serial line Internet protocol (SLIP), point-to-point protocol (PPP), PPP over ethernet, asynchronous transfer mode (ATM), and Bluetooth. The network layer is covered in the next logical part, where the authors interleave an excellent introduction to TCP/IP concepts with their Linux specific implementation. This part covers the implementation of routing tables, address resolution protocol (ARP), netfilter, firewall, network address translation, and the next generation of the Internet protocol (IP), IPv6. The TCP implementation and the user datagram protocol (UDP) kernel structures are addressed extensively in a fifth logical part. A final logical part, covering the user level structures (sockets), covers implementation of the well-known socket network programming library.

This book is a superb introduction to the Linux TCP/IP stack, with a perfect mix of generic TCP/IP material and its Linux specific implementation. Targeting readers interested in operating systems and computer networking, this book is very interesting, and very pleasant to read.