troubleshooting linux firewalls
There aren't many up-to-date books on Linux firewalls, so when I saw this one come out, I immediately grabbed it. As the title suggests, this book deals more with troubleshooting firewalls rather than creating them. However, there's a little bit of everything in this book.
The first part gets all the theory out of the way: Risk Management, steps to troubleshooting, why you should use a firewall, etc. To me, theory is always dry, but the authors made it mostly bearable. I found the Risk Management subjects to be not as boring as in the other books I've read and the troubleshooting techniques were rather common sense but nice to have as a hard-copy reference.
Part Two deals with some firewall basics. It starts with a quick summary of the OSI model and goes into a quick introduction to Netfilter and IPTables. We're given a basic model of a firewall with a lot of nice options turned on and explained. A couple newer patches are shown as well -- including port scan detection and reading strings from packets. It's a complete firewall except for the fact that no services are configured at all -- which seemed a little odd. At the end of this section is a quick introduction to diagnosing a firewall. Telnet, sniffers, and scanners are all included.
Part Three is all about that missing section of the firewall from Part Two. It's split up into many topics including Layer Two topics, Web, Instant Messaging, and VPNs. A nice chapter on testing firewalls with iplog is also included. This section is what the book is all about: using a firewall in conjunction with different services and how to troubleshoot when they have problems. You can read this section from beginning to end or you can simply use it as a reference. Each chapter is complete in explaining the designated topic and when you're finished reading, you'll walk away knowing a new tool or two.
I enjoyed this book for two reasons: It was nice to read an up-to-date book on firewalls and I walked away from it learning quite a few things. It'll provide a great future reference, too -- whenever I set a firewall up that will be including a service this book covers, I'll be confident in the tips this book offers.
9/10
