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System administrators need to stay ahead of new security vulnerabilities that leave their networks exposed every day. A firewall and an intrusion detection systems (IDS) are two important weapons in that fight, enabling you to proactively deny access and monitor network traffic for signs of an attack.

Linux Firewalls discusses the technical details of the iptables firewall and the Netfilter framework that are built into the Linux kernel, and it explains how they provide strong filtering, Network Address Translation (NAT), state tracking, and application layer inspection capabilities that rival many commercial tools. You'll learn how to deploy iptables as an IDS with psad and fwsnort and how to build a strong, passive authentication layer around iptables with fwknop.

Concrete examples illustrate concepts such as firewall log analysis and policies, passive network authentication and authorization, exploit packet traces, Snort ruleset emulation, and more with coverage of these topics:

  • Passive network authentication and OS fingerprinting

  • iptables log analysis and policies

  • Application layer attack detection with the iptables string match extension

  • Building an iptables ruleset that emulates a Snort ruleset

  • Port knocking vs. Single Packet Authorization (SPA)

  • Tools for visualizing iptables logs

Perl and C code snippets offer practical examples that will help you to maximize your deployment of Linux firewalls. If you're responsible for keeping a network secure, you'll find Linux Firewalls invaluable in your attempt to understand attacks and use iptables-along with psad and fwsnort-to detect and even prevent compromises.

Subscriber Reviews

Average Rating: 4.5 out of 5 rating Based on 2 Ratings

"I like this book. Network Security and Linux" - by Arthur J Spencer on 07-NOV-2013
Reviewer Rating: 1 star rating2 star rating3 star rating4 star rating5 star rating
I started looking for a book to brush up on iptables and was taken through a great ride talking about packet formats and how basically free unix tools provide you with an awesome amount of protection and flexibility.  My background is network security (CISSP, GCIH, CEH) with a DDOS background and I am motivated to invest time in this book to learning some of iptables intricacies and adding PSAD and FWSNORT together to play with some things Ive been thinking about.  <<Anyway good read if you want to get deep into this topic and written well.>>
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"A well-structured iptables resource" - by Philip Storry on 05-JUL-2011
Reviewer Rating: 1 star rating2 star rating3 star rating4 star rating5 star rating
These days, most kernels probably already have iptables in them.  So starting off with compiling iptables into your kernel probably seems like overkill...
But don't let that put you off this book.  It may show some signs of age, but this is hardly the kind of field where the basics change every day.
This book is a solid resource for configuring iptables and for monitoring its output - and it shows you how to build on iptables with tools like PSAD and Snort to create effective multi-layer defence and reporting.

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