Author: Al Anderson & Ryan Benedetti
Publisher: O'Reilly, 2009
Aimed at: Apprentice network administrators
Pros: Useful grounding in theory and practical implementation of networks
Cons: Runs out of space for important topics
Reviewed by: Mike James
Head First books are an acquired taste and perhaps I'm acquiring it at long last. They are uniformly a riot of photos, freehand drawings, quizzes, activities and annotations. All, in principle, designed to help you remember the material in question. In many cases, to my mind at least, the presentation doesn't mirror the linear progression inherent in many subjects. Perhaps understanding networks suits the free form presentation - but I think it's successful more because the authors have managed to retain a logical order to what they have to tell you.
This is a very useful book that can teach you the foundations of networking. It's not perfect but more because of its choice of topics. It starts off considering the hardware at its most basic level - the wiring. It presents a long discussion of cables, including fibre optics, connectors and testing equipment ranging from cable identifiers, multi-meters, oscilloscopes and even logic analysers. I doubt the average network admin could justify a logic analyser, or master the intricacies of using an oscilloscope, but it's good to know they exist. More usefully it deals with the physical problems of wiring - mostly walls and how to get cables from one side to the other! Patch boards and cables complete the picture and we move on to binary numbers, MAC addresses and the difference between hubs and switches.
The book is particularly good on the way IP packets are embedded in Ethernet packets and how routers work. From here on the coverage gets increasingly patchy and idiosyncratic. We get an explanation of how DNS works but topics such as NAT and DCHP are covered as part of a chapter on WiFi. Surprisingly, despite covering WiFi in detail, the real problem of wireless security is hardly dealt with apart from the obvious - it’s a good idea and you need to supply a password. The later chapters deal with general network security - types of attack, firewalls and even the psychology of internal attacks from employees. At the end there is a summary of what has been left out and this indicates the main shortcoming of the book - it runs out of space and therefore misses out important topics such as virtual networks.
Overall the book presents a strange mix of the academic theoretical and the really practical. It's also worth mentioning the overall bias for Cisco equipment, Linux and open source implementations and the command line rather than any GUI. None of these biases are a real problem if you concentrate on the principles and this is how it should be. However the real failure of the book is that it concentrates too much on the very, very basics in the early pages only to run out of space for important topics later in the book with the situation made worse by the inclusion of some additional topics such as WiFi that could have been the subject of another book. My recommendation would be to split the current volume into two or perhaps three expanded texts - networking basics, networking advanced and networking esoterics.
If you need a basic grounding in how networks actually work and how to make them work at the wiring and addressing level then this is a good choice - it runs out of steam later but mainly because it runs out of pages!