• Linux Firewalls, Third Edition
• Table of Contents
• Copyright
• About the Authors
• Acknowledgments
• We Want to Hear from You!
• Reader Services
• Introduction
• The Purpose of This Book
• Who Should Read This Book
• Linux Distribution
• Errors in This Book
• Companion Website
• Part I. Packet-Filtering and Basic Security Measures
  • Chapter 1. Preliminary Concepts Underlying Packet-Filtering Firewalls
    • The OSI Networking Model
    • The IP
    • Transport Mechanisms
    • Don't Forget ARP
    • Hostnames and IP Addresses
    • Routing: Getting a Packet from Here to There
    • Service Ports: The Door to the Programs on Your System
    • Summary
  • Chapter 2. Packet-Filtering Concepts
    • A Packet-Filtering Firewall
    • Choosing a Default Packet-Filtering Policy
    • Rejecting Versus Denying a Packet
    • Filtering Incoming Packets
    • Filtering Outgoing Packets
    • Private Versus Public Network Services
    • Summary
  • Chapter 3. iptables: The Linux Firewall Administration Program
    • Differences Between IPFW and Netfilter Firewall Mechanisms
    • Basic iptables Syntax
    • iptables Features
    • iptables Syntax
    • Summary
  • Chapter 4. Building and Installing a Standalone Firewall
    • iptables: The Linux Firewall Administration Program
    • Initializing the Firewall
    • Protecting Services on Assigned Unprivileged Ports
    • Enabling Basic, Required Internet Services
    • Enabling Common TCP Services
    • Enabling Common UDP Services
    • Filtering ICMP Control and Status Messages
    • Logging Dropped Incoming Packets
    • Logging Dropped Outgoing Packets
    • Denying Access to Problem Sites Up Front
    • Installing the Firewall
    • Summary
• Part II. Advanced Issues, Multiple Firewalls, and Perimeter Networks
  • Chapter 5. Firewall Optimization
    • Rule Organization
    • User-Defined Chains
    • Optimized Example
    • What Did Optimization Buy?
    • Summary
  • Chapter 6. Packet Forwarding
    • The Limitations of a Standalone Firewall
    • Basic Gateway Firewall Setups
    • LAN Security Issues
    • Configuration Options for a Trusted Home LAN
    • Configuration Options for a Larger or Less Trusted LAN
    • A Formal Screened-Subnet Firewall Example
    • Converting the Gateway from Local Services to Forwarding
    • Summary
  • Chapter 7. NATNetwork Address Translation
    • The Conceptual Background of NAT
    • iptables NAT Semantics
    • Examples of SNAT and Private LANs
    • Examples of DNAT, LANs, and Proxies
    • Summary
  • Chapter 8. Debugging the Firewall Rules
    • General Firewall-Development Tips
    • Listing the Firewall Rules
    • Checking the Input, Output, and Forwarding Rules
    • Interpreting the System Logs
    • Checking for Open Ports
    • Checking for Open Ports
• Part III. Beyond iptables
  • Chapter 9. Intrusion Detection and Response
    • Detecting Intrusions
    • Symptoms Suggesting That the System Might Be Compromised
    • What to Do If Your System Is Compromised
    • Incident Reporting
    • Summary
  • Chapter 10. Intrusion Detection Tools
    • Intrusion Detection Toolkit: Network Tools
    • Rootkit Checkers
    • Filesystem Integrity
    • Log Monitoring
    • How to Not Become Compromised
    • Summary
  • Chapter 11. Network Monitoring and Attack Detection
    • Listening to the Ether
    • TCPDump: A Simple Overview
    • Using TCPDump to Capture Specific Protocols
    • Automated Intrusion Monitoring with Snort
    • Monitoring with ARPWatch
    • Summary
  • Chapter 12. Filesystem Integrity
    • Filesystem Integrity Defined
    • Installing AIDE
    • Configuring AIDE
    • Monitoring AIDE for Bad Things
    • Cleaning Up the AIDE Database
    • Changing the Output of the AIDE Report
    • Defining Macros in AIDE
    • The Types of AIDE Checks
    • Summary
  • Chapter 13. Kernel Enhancements
    • Security Enhanced Linux
    • Greater Security with GrSecurity
    • A Quick Look Around the Kernel
    • To Patch or Not to Patch
    • Using a GrSecurity Kernel
    • GrSecurity
    • Conclusion: Custom Kernels
• Part IV. Appendices
  • Appendix A. Security Resources
    • Security Information Sources
    • Reference Papers and FAQs
    • Books
  • Appendix B. Firewall Examples and Support Scripts
    • iptables Firewall for a Standalone System from Chapter 4
    • Optimized iptables Firewall from Chapter 5
    • iptables Firewall for a Choke Firewall from Chapter 6
  • Appendix C. VPNs
    • Overview of Virtual Private Networks
    • VPN Protocols
    • Linux and VPN Products
    • VPN Configurations
    • Connecting Networks
    • VPN and Firewalls
    • Summary
  • Appendix D. Glossary
• Index
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