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# Firewall and Proxy Server HOWTO

## Mark Grennan, `mark@grennan.com`

v0.80, Feb. 26, 2000

This document is designed to describe the basics of firewall systems and give you some detail on setting up both a filtering and proxy firewall on a Linux based system. An HTML version of this document is available at http://www.grennan.com/Firewall-HOWTO.html

## 1. Introduction

- 1.1 Feedback
- 1.2 Disclaimer
- 1.3 Copyright
- 1.4 My Reasons for Writing this
- 1.5 Further Readings

## 2. Understanding Firewalls

- 2.1 Firewall Politics
- 2.2 Types of Firewalls

## 3. Firewall Architecture

- 3.1 Dial-up Architecture
- 3.2 Single Router Architecture
- 3.3 Firewall with Proxy Server
- 3.4 Redundent Internet Configuration

## 4. Setting up the Linux Filtering Firewall

- 4.1 Hardware requirements

## 5. Software requirements

- 5.1 Selecting a Kernel
- 5.2 Selecting a proxy server

## 6. Preparing the Linux system

- 6.1 Compiling the Kernel
- 6.2 Configuring two network cards
- 6.3 Configuring the Network Addresses
- 6.4 Testing your network
- 6.5 Securing the Firewall

## 7. IP filtering setup (IPFWADM)

## 8. IP filtering setup (IPCHAINS)

## 9. Installing a Transparent SQUID proxy

## 10. Installing the TIS Proxy server

- 10.1 Getting the software
- 10.2 Compiling the TIS FWTK
- 10.3 Installing the TIS FWTK
- 10.4 Configuring the TIS FWTK

## 11. The SOCKS Proxy Server

- 11.1 Setting up the Proxy Server
- 11.2 Configuring the Proxy Server
- 11.3 Working With a Proxy Server
- 11.4 Drawbacks with Proxy Servers

## 12. Advanced Configurations

- 12.1 A large network with emphasis on security

## 13. Making Management Easy

- 13.1 Firewall tools
- 13.2 General tools

## 14. Defeating a Proxy Firewall

## 15. APPENDEX A - Example Scripts

- 15.1 RC Script useing GFCC
- 15.2 GFCC script
- 15.3 RC Script without GFCC

## 16. APPENDEX B - An VPN RC Script for RedHat

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