Resumen de Netfilter's connection tracking system
Filtering policies based uniquely on packet header information areobsolete. These days, stateful firewalls provide advanced mechanism to let sysadmins and security experts define more intelligent policies. This article describes the implementation details of the connection tracking system privided by the Netfilter project and also presents the required background to understand it, such as an understanding of the Netfilter framework. This article will be the perfect complement to understanding the subsystem that enables the staterful firewall avaible in any recent Linux kernel.
