Part I: Packet Filtering and Basic Security Measures
Chapter 1 Preliminary Concepts Underlying Packet-Filtering Firewalls
Chapter 2 Packet-Filtering Concepts
Chapter 3 iptables: The Legacy Linux Firewall Administration Program
Chapter 4 nftables: The Linux Firewall Administration Program
Chapter 5 Building and Installing a Standalone Firewall

Part II: Advanced Issues, Multiple Firewalls, and Perimeter Networks
Chapter 6 Firewall Optimization
Chapter 7 Packet Forwarding
Chapter 8 NAT—Network Address Translation
Chapter 9 Debugging the Firewall Rules
Chapter 10 Virtual Private Networks

Part III: Beyond iptables and nftables
Chapter 11 Intrusion Detection and Response
Chapter 12 Intrusion Detection Tools
Chapter 13 Network Monitoring and Attack Detection
Chapter 14 Filesystem Integrity

Part IV: Appendices
A Security Resources
B Firewall Examples and Support Scripts
C Glossary
D GNU Free Documentation License
Index