I was invited by Lucian to review this book. Lucian actually sent me a copy of this book for me to read and i was happy upon receiving it. Well, i am someone who loves firewall and security stuff especially linux and cisco. This book is absolutely amazing. For beginners, there are a lot of technical configuration you can read and learn and for experts, this book will guide you to some topic that might interest you. I would really want to put this book into practice, but however base on my current situation, i will only have the time to read and understand the concept. I would highly rate this book a 4.5/5 and anyone who wants to learn firewall at a low level.