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:

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