Netfilter and IPTables: A Structural Examination

In this paper a study is made of the Linux packet manipulation framework, Netfilter, and the packet matching system built on top of it, IPTables. The structure of both systems is discussed, detailing both their arrangement as well as the mechanism through which they perform their functions. Also discussed are features of the framework germane to its role as a firewall. Additionally, installation of the system is covered. Finally, usage of the package is detailed. Ultimately, the discussion herein examines in detail the Netfilter/IPTables system, extending beyond a simple 'how-to' style document and providing the reader with a deeper understanding of the technology.