The Netfilter firewall built into Linux provides capabilities that rival many commercial firewalls. 'Linux Firewalls: Attack Detection And Response' explores using Netfilter as an intrusion detection system (IDS) to create a highly secure network. The book discusses passive network authentication; Netfilter log analysis and policies; exploit packet traces and Snort ruleset emulation with Netfilter rules; and more. Perl and C code snippets are included to help readers maximize the effectiveness of Netfilter.