IPFWADM FAQ - Frequently asked questions

by DREAMWVR.COM dreamwvr@dreamwvr.com

1. Meta-questions

• 1.1 Where do I get this document?
• 1.2 Where do I send questions, corrections etc. about this document?

2. IPFWADM Basics

• 2.1 What is ipfwadm?
• 2.2 Why should I use it?
• 2.3 What kinds of attacks does ipfwadm protect against?
• 2.4 What kind of attacks does ipfwadm not protect against?
• 2.5 How does it work?

3. Obtaining and installing ipfwadm

• 3.1 What is the latest version of ipfwadm?
• 3.2 May I legally run ipfwadm?
• 3.3 What about commercial use of ipfwadm?
• 3.4 Where can I obtain ipfwadm?
• 3.5 How do I install it?
• 3.6 Does it make sense to install ipfwadm if i am using UNIX?
• 3.7 Where do I get help?
• 3.8 Are there any versions for other operating systems than Linux?
• 3.9 What about accounting of ipfwadm?

4. ipfwadm Usage

• 4.1 How do i see a detailed analysis of my rules for masquerading?
• 4.2 How do i check to see if a specific packet would be accepted, denied, or rejected by one of my specific firewalls?
• 4.3 What is the difference between rejecting and denying a packet in regards to the use of ipfwadm?
• 4.4 How do i enable ip forwarding from the command line?
• 4.5 How do i make IP forwarding automatically enabled upon bootup... whatever that is on Linux?
• 4.6 Where exactly do i place my ipfwadm rules that i wish to have run when i bring up my system so they run without intervention?
• 4.7 Why doesn't my browser's ftp work for me when i can access ok from other ftp clients and the command line just fine?
• 4.8 Can I use ipfwadm to protect services like ftp or POP?
• 4.9 Why is it important that i for me to start by denying access to literally all the firewalls that are controlled by ipfwadm?
• 4.10 Can you present a basic example for analysis?

5. Problems

• 5.1 Are there known compiling problems with ipfwadm?
• 5.2 Does glibc2 cause problems?
• 5.3 Are there any problems with transparent proxy?

6. Miscellaneous

• 6.1 What known security bugs exist in which versions of ipfwadm?
• 6.2 How widespread is use of ipfwadm?
• 6.4 Credits