While Linux firewalls are inexpensive and quite reliable, they lack the supportcomponent of their commerical counterparts. As a result, most users of Linuxfirewalls have to resort to mailing lists to solve their problems. Our authorshave scoured firewall mailing lists and have compiled a list of the most oftenencountered problems in Linux firewalling. This book takes a Chilton's manualdiagnostic approach to solving these problems.The book begins by presenting the two most common Linux firewallconfigurations and demonstrates how to implement these configurations in animperfect network environment, not in an ideal one. Then, the authors proceedto present a methodology for analyzing each problem at various network levels:cabling, hardware components, protocols, services, and applications. Theauthors include diagnostic scripts which the readers can use to analyze andsolve their particular Linux firewall problems. The reference distributions areRed Hat and SuSE (for international market).

When something goes wrong with your Linux firewall, you need to fix it—right now. You don't have time for endless newsgroup searches, confusing man pages, emails to the developers... it's an emergency! One book brings together all the step-by-step solutions and proven problem-solving techniques you'll need when the time comes: Troubleshooting Linux® Firewalls.

Authors Michael Shinn and Scott Shinn are among the world's leading firewall experts; they've even been hired to protect computer security at the White House. In this book, they cover every area where Linux firewalls can go wrong: rules and filtering problems, Layer 2/3/4 issues, trouble with individual services, DNS/DHCP failures, even misconfigured VPNs. They also present an easy, start-to-finish troubleshooting methodology that'll help you identify even the newest or most obscure firewall problem fast—and solve it!

Inside, you will find in-depth information on the following areas:

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What you must know about iptables and netfilter to troubleshoot and avoid problems
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Using loggers, sniffers, and other tools to diagnose even the most obscure firewall problems
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Making sure your firewall rules work the way they're supposed to
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Resolving problems with Network Address Translation and IP Forwarding
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Troubleshooting SMTP, Apache, Squid, NFS, FTP, instant messaging, and other Web-based services
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Finding and fixing common problems with IPsec VPN configuration
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Making your firewalls more failure-resistant: recommendations from the experts

If you depend on a Linux firewall, what will you do if it goes down? With Troubleshooting Linux® Firewalls, you can be confident that the solutions are right at hand—so you can sleep at night!