Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

The Shorewall Logo is by Gareth Davies of Thusa and is licensed under the Creative Commons Attribution-Share Alike 2.5 South Africa License. To view a copy of this licence, visit http://creativecommons.org/licenses/by-sa/2.5/za/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California 94105, USA.

2009-01-14

Table of Contents

Current Shorewall Releases
Getting Started with Shorewall
Looking for Information?
Glossary
What is Shorewall?
License

Important Notice to users of Shorewall Multi-ISP Feature -- UPDATED 7 November 2007

Important Notice to users of BRIDGING=Yes

Important Notice to users running Kernel 2.4

Current Shorewall Releases

The current Stable Release version is 4.2.4 which contains IPv6 support.

• Here are the release notes
  
• Here are the known problems.

  Read more about the Shorewall 4.x releses here.
  

Getting Started with Shorewall

New to Shorewall? Download the current Stable version (see above) then select the QuickStart Guide that most closely matches your environment and follow the step by step instructions.

Looking for Information?

The Documentation Index is a good place to start as is the Site Search in the frame above.

Glossary

• Netfilter - the packet filter facility built into the 2.4 and later Linux kernels.

• ipchains - the packet filter facility built into the 2.2 Linux kernels. Also the name of the utility program used to configure and control that facility. Netfilter can be used in ipchains compatibility mode.

• iptables - the utility program used to configure and control Netfilter. The term 'iptables' is often used to refer to the combination of iptables+Netfilter (with Netfilter not in ipchains compatibility mode).

• iptables-restore - a utility program that used to configure and control Netfilter. Unlike iptables, which performs only one operation per execution, iptables-restore can configure an entire ruleset in one execution. It takes much less time to configure a firewall using iptables-restore than it does using iptables.
  
  
• Shorewall-shell - the legacy Shorewall rules compiler written in Bourne Shell. It generates a shell script that uses iptables to configure the firewall.
  
  
• Shorewall-perl - a Shorewall rules compiler written in Perl. It generates a shell script that uses iptables-restore to configure the firewall.
  

What is Shorewall?

The Shoreline Firewall, more commonly known as "Shorewall", is a high-level tool for configuring Netfilter. You describe your firewall/gateway requirements using entries in a set of configuration files. Shorewall reads those configuration files and generates a shell script. That shell script  uses the iptables or iptables-restore utility to configure Netfilter to match your requirements. Shorewall can be used on a dedicated firewall system, a multi-function gateway/router/server or on a standalone GNU/Linux system. Shorewall does not use Netfilter's ipchains compatibility mode; as a consequence, Shorewall can take advantage of Netfilter's connection state tracking capabilities to create a stateful firewall.

The current version of Shorewall can configure both IPv4 and IPv6 firewalls.
 
Shorewall is not a daemon. Once Shorewall has configured Netfilter, it's job is complete and there is no Shorewall code left running in the system. The /sbin/shorewall program can be used at any time to monitor the Netfilter firewall.

Shorewall is not the easiest to use of the available iptables configuration tools but I believe that it is the most flexible and powerful. So if you are looking for a simple point-and-click set-and-forget Linux firewall solution that requires a minimum of networking knowledge, I would encourage you to check out the following alternatives:

• kmyfirewall
  

• Firestarter
  

On the other hand, if you are looking for a Linux firewall solution that can handle complex and fast changing network environments then Shorewall is a logical choice.

To see some of the many things that you can do with Shorewall, see the Shorewall Features page.

License

This program is free software; you can redistribute it and/or modify it under the terms of Version 2 of the GNU General Public License as published by the Free Software Foundation.

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 detail.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

Leaf

LEAF is an open source project which provides a Firewall/router on a floppy, CD or CF. Several LEAF distributions including Bering and Bering-uClibc use Shorewall as their Netfilter configuration tool.

OpenWRT

OpenWRT is a project which provides open source firmware for Linksys WRT54G wireless routers. Two different Shorewall packages are available for OpenWRT.

Donations

Shorewall is free but if you try it and find it useful, please consider making a donation to the Alzheimer's Association or to the Starlight Children's Foundation.

Thank You