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).