Linux Firewalls

Linux iptables Pocket Reference

Linux Firewalls: Attack Detection and Response with iptables, psad, and fwsnort

Linux Routers: A Primer for Network Administrators (2nd Edition)

Linux Firewalls: Enhancing Security with nftables and Beyond (4th Edition)

Snort IDS and IPS Toolkit (Jay Beale's Open Source Security)

Self-Paced Training Kit (Exam 70-640) Configuring Windows Server 2008 Active Directory (MCTS) (2nd Edition) (Microsoft Press Training Kit)

UNIX and Linux System Administration Handbook, 4th Edition

Linux Security Cookbook

Linux Networking Cookbook: From Asterisk to Zebra with Easy-to-Use Recipes

Starting Out with Programming Logic and Design (4th Edition)