Linux IPCHAINS-HOWTO

Paul Russell Paul.Russell@rustcorp.com.au

1. Introduction

• 1.1 What?
• 1.2 Why?
• 1.3 How?
• 1.4 Where?

2. Packet filtering basics.

• 2.1 What?
• 2.2 Why?
• 2.3 How?

3. IP firewalling chains.

• 3.1 How packets traverse the filters.
• 3.2 Useful Examples

4. Miscellaneous.

• 4.1 How to organise your firewall rules.
• 4.2 What not to filter out.
• 4.3 Filtering out Ping of Death.
• 4.4 Filtering out Teardrop and Bonk.
• 4.5 Filtering out Fragment Bombs.
• 4.6 Changing firewall rules.
• 4.7 How do I set up IP spoof protection?
• 4.8 Advanced projects.
• 4.9 Future enhancements.

5. Common problems.

• 5.1 Masquerading/forwarding doesn't work!
• 5.2 Wildcard interfaces don't work!
• 5.3 TOS doesn't work!
• 5.4 ipautofw and ipportfw don't work!
• 5.5 xosview is broken!
• 5.6 Segmentation fault with -j REDIRECT!
• 5.7 I can't set masquerading timeouts!
• 5.8 I want to firewall IPX!

6. Appendix: Differences between ipchains and ipfwadm

• 6.1 Quick-Reference table.
• 6.2 Examples of translated ipfwadm commands

7. Appendix: Using the ipfwadm-wrapper script.

8. Appendix: thanks.