When I rst started using OpenBSD sometime in 1999, it certainly wasn't because I wanted to write a book about it. All I needed was a stable server for my home network, something I could con gure and forget about. I tried all obvious suspects: FreeBSD, NetBSD, OpenBSD, and four or ve different Linux distributions, My choice was OpenBSD, because it installed without problems, was easy to con gure, and did not have the infuriating problems with NFS that plagued me on Linux at that time. FreeBSD and NetBSD lost their race at the installation stage, after they failed to recognize some pieces of the hardware I was using. It | - free books & magazines Building Firewalls with OpenBSD and PF Coming soon from The OpenBSD Gazetteer by Jacek Artymiak Building Virtual Private Networks with FreeBSD, NetBSD, OpenBSD, Linux, Apple Mac OS X, and Microsoft Windows by Jacek Artymiak The FreeBSD Gazetteer by Jacek Artymiak The NetBSD Gazetteer by Jacek Artymiak Scripting Caligari trueSpace with Python by Jacek Artymiak Scripting Adobe Photoshop with JavaScript by Jacek Artymiak Youwill find more information under this address: Building Firewalls with OpenBSD and PF Jacek Artymiak Second Edition Lublin Building Firewalls with OpenBSD and PF by Jacek Artymiak Published by: Jacek Artymiak email: openbsdpf-ed-02@ www: Copyright © 2003 Jacek Artymiak All rights reserved. No part of this pubication may be reproduced, stored in aretrievalsystem, or transmitted, in anyform or by anymeans, electronic, mechanical, photocopying, recording, or otherwise, without the prior consent of the publisher. First edition 2003 Second edition 2003 Printed in Poland 03 10 987654321 ISBN: 83-916651-1-9 The author and the publisher disclaim anyand all liability for the use of information and programs contained in this book. All trademarks mentioned in this book are the sole property of their owners. Sowa - Print on demand phone: +48 (22) 431-81-40 To Gosia TableofContents Preface . 1 Acknowledgments . 3 Chapter 1: Introduction . 5 WhyDoWeNeed to Secure Our Networks . 5 WhyDoWeNeed Firewalls . 7 WhyOpen Source Software . 7 WhyOpenBSD and pf . 9 Cryptographyand Law. 11 HowThis Book Is Organized . 12 Typographic Conventions Used in This Book . 14 Staying in Touch with the OpenBSD Community . 14 Getting in Touch with the Author . 15 Chapter 2: Firewall Designs . 17 Define Your Local Packet Filtering Policy. 17
