By Gregor N. PurdyPublished by O'Reilly Media (http://oreilly.com/catalog/9780596005696/)Firewalls, Network Address Translation (NAT), network logging and accounting are all provided by Linux's Netfilter system, also known by the name of the command used to administer it, iptables. The iptables interface is the most sophisticated ever offered onLinux and makes Linux an extremely flexible system for any kind of network filtering you might do. Large sets of filtering rules can be grouped in ways that makes it easy to test them and turn them on and off.Do you watch for all types of ICMP traffic--some of them quite dangerous? Can you take advantage of stateful filtering to simplify the management of TCP connections? Would you like to track how much traffic of various types you get?This pocket reference will help you at those critical moments when someone asks you to open or close a port in a hurry, either to enable some important traffic or to block an attack. The book will keep the subtle syntax straight and help you remember all the values you have to enter in order to be as secure as possible. The book has an introductory section that describes applications,followed by a reference/encyclopaedic section with all the matches and targets arranged alphabetically. Superb Reading FeaturesThrough a partnership between O'Reilly Media and Lexcycle, this app includes the same features that have made Stanza an iPhone phenomenon with over a million downloads:* Full book text search* Several fonts and themes to choose from* Built-in dictionary* The ability to add annotations* Landscape view* Extensive cross-referencing and working hyperlinks* Zoom function for images and screenshotsAbout O'Reilly MediaO'Reilly Media spreads the knowledge of innovators through its books, online services, magazines, research, and conferences. Whether it's delivered in print, online, or in person, everything O'Reilly produces reflects the company's unshakeable belief in the power of information to spur innovation. Learn more about Ebooks from O'Reilly at oreilly.com/ebooks.About LexcycleLexcycle is the creator of Stanza Bookbinder which was used to create this standalone book application. Stanza Bookbinder is based on the popular iPhone Ebook reading application, Stanza. For more information about Stanza, visit www.lexcycle.com.