The Definitive Guide to Building Firewalls with Linux As the security challenges facing Linux system and network administrators have grown, the security tools and techniques available to them have improved dramatically. In Linux(R) Firewalls, Fourth Edition, long-time Linux security expert Steve Suehring has revamped his definitive Linux firewall guide to cover the important advances in Linux security. An indispensable working resource for every Linux administrator concerned with security, this guide presents comprehensive coverage of both iptables and nftables. Building on the solid networking and firewalling foundation in previous editions, it also adds coverage of modern tools and techniques for detecting exploits and intrusions, and much more. Distribution neutral throughout, this edition is fully updated for today's Linux kernels, and includes current code examples and support scripts for Red Hat/Fedora, Ubuntu, and Debian implementations. If you're a Linux professional, it will help you establish an understanding of security for any Linux system, and for networks of all sizes, from home to enterprise.Inside, you'll find just what you need to * Install, configure, and update a Linux firewall running either iptables or nftables* Migrate to nftables, or take advantage of the latest iptables enhancements* Manage complex multiple firewall configurations* Create, debug, and optimize firewall rules* Use Samhain and other tools to protect filesystem integrity, monitor networks, and detect intrusions* Harden systems against port scanning and other attacks* Uncover exploits such as rootkits and backdoors with chkrootkit