This document describes how to enable IP masquerade feature on a Linux host, allowing connected computers that do not have registered Internet IP addresses to connect to the Internet through your Linux box. It is possible to connect your machines to the Linux host with ethernet, as well as other kinds of connection such as a dialup ppp link. This document will emphasize on ethernet connection, since it should be the most likely case.
This document is intended for users using stable kernels 2.2.x and 2.0.x. Older kernels such as 1.2.x are NOT covered.
I find it very confusing as a new user setting up IP masquerade on a newer kernel, i.e. 2.x kernel. Although there is a FAQ and a mailing list, there is no document dedicates on that; and there are some requests on the mailing list for such a HOWTO. So, I decided to write this up as a starting point for new users, and possibly a building block for knowledgeable users to build on for documentation. If you think I'm not doing a good job, feel free to tell me so that I can make it better.
This document is heavily based on the original FAQ by Ken Eves , and numerous helpful messages in the IP Masquerade mailing list. And a special thanks to Mr. Matthew Driver whose mailing list message inspired me to set up IP Masquerade and eventually writing this.
Please feel free to send any feedback or comments to and if we've mistaken on any information, or if any information is missing. Your invaluable feedback will certainly be influencing the future of this HOWTO!
This HOWTO is meant to be a quick guide to get your IP Masquerade working in the shortest time. As I am not a technical writer, you may find the information in this document not as general and objective as it can be. The latest news and information can be found at the IP Masquerade Resource web page that we maintained. If you have any technical questions on IP Masquerade, please join the IP Masquerade Mailing List instead of sending email to me since I have limited time, and the developers of IP_Masq are more capable of answering your questions.
The latest version of this document can be found at the IP Masquerade Resource, which also contains the HTML and postscript version:
This document is copyright(c) 1999 Ambrose Au, and it's a free document. You can redistribute it under the terms of the GNU General Public License.
The information and other contents in this document are to the best of my knowledge. However, IP Masquerade is experimental, and there is chance that I make mistakes as well; so you should determine if you want to follow the information in this document.
Nobody is responsible for any damage on your computers and any other losses by using the information on this document. i.e.
THE AUTHOR AND MAINTAINERS ARE NOT RESPONSIBLE FOR ANY DAMAGES INCURRED DUE TO ACTIONS TAKEN BASED ON THE INFORMATION IN THIS DOCUMENT.
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