Current version - 0.12.0

Introduction

Mason is a tool that interactively builds a firewall using Linux' ipfwadm or ipchains firewalling. You leave mason running on the firewall machine while you are making all the kinds of connections that you want the firewall to support (and want it to block). Mason gives you a list of firewall rules that exactly allow and block those connections.

Mason was specifically designed to make it possible for anyone with the ability to generally find their way around a Linux system to build a reasonably good packet filtering firewall for any and every system under their control. It takes care of all the low level grunt work; all you need to do is follow the instructions and be able to run all the TCP/IP applications that need to be supported.

The real work of the package is done by the mason script. Its job is to convert the log entries that the Linux kernel produces into ipfwadm or ipchains commands that you can use in your own firewall.

In order to make it easy to use, I have included a rudimentary tool called mason-gui-text. It's a very simple shell that handles the setup and creation process for those that want to be led through the process. It would sincerely like to see it replaced with a nicer interface.

Features

Mason supports the following:

Disclaimers

I've included a copy of the disclaimers. Like all GNU programs:

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

Unfortunately, because this program is so deeply involved in the security of the systems on which it is run, I need to add this disclaimer as well:

        This program offers an aid to creating firewall rules.  It offers
ABSOLUTELY NO intelligence in deciding what should be allowed or
disallowed.  It has ABSOLUTELY NO ability to understand your security
policy and implement it.  YOU are responsible for reviewing the rules and
massaging them to fit your needs.
        While the documentation in mason.txt attempts to provide some
general guidelines on how to use Mason, please remember:  the author has
no knowledge of what you want your firewall to do and has not tailored the
documentation or program to specially fit your needs.  If there is ever a
discrepancy between your needs and the program output or your needs and
the documentation, the program and/or documentation are _dead_ _wrong_.

Downloading and installing

Here are the various versions available for download, most recent at the top.

Here's how to install:

Here are the individual files you can download. Note that all of the following files are included in the latest version:

Additional resources

Author, credits, feedback, copyright

If you have comments, suggestions, problems, ideas, flames, patches, whatever, I'd like to hear them. I'd even be interested in hearing where Mason fell short for your needs. My permanent email address is wstearns@pobox.com. The permanent web site for the software is http://www.pobox.com/~wstearns/mason/.

If you choose to send me actual mason firewall rules and choose to hide the IP addresses and/or networks for security reason, that's fine, but please replace them with something that describes their general use so I can make sense of them. For example: 

cat myrules | sed -e 's@11.22.33.44/32@fw-outside@' \
                  -e 's@192.168.1.1/32@fw-inside@' \
                  -e 's@192.168.1.0/24@inside-net@' \
>myrules.mailable
- or something like that.

This page, the Mason script, and the other files in the Mason package are Copyright (c) 1998 by William Stearns wstearns@pobox.com. They are released under the GNU GPL, which is included in the package. If you did not recieve a copy of this license, please contact the author for a copy (see the top of the Mason script for contact information for the author and the Free Software Foundation).

William is also the author of buildkernel, the automated Linux kernel builder, and other minor shell scripts.

Thanks

Many thanks to Dave Stern, who has offered suggestions on how to improve Mason and helped with beta testing early versions. Maybe someday I'll tell him they were prerelease versions... :-)

A special thank you to all the authors in the Linux movement. In a small way, the code I return to the community is my way of paying back my incredible debt to the people who came before me.

As always, many thanks to my wife Debra, who has shown amazing patience with my Linux related projects. Many thanks, my love.

Last edited: 3/22/99

Best viewed with something that can show web pages... <grin>