shorewall_code/Shorewall-Website/shorewall_index.htm
teastep 0cb16ef3b1 Shorewall-2.0.3c
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<h1>Shorewall 2.0</h1>
<span style="font-weight: bold;">Tom Eastep</span><br>
<br>
The information on this site
applies only to 2.0.x releases of
Shorewall. For older versions:<br>
<ul>
<li>The 1.4 site is <a href="http://www.shorewall.net/1.4"
target="_top">here.<br>
</a></li>
<li>The 1.3 site is <a href="http://www.shorewall.net/1.3"
target="_top">here.</a></li>
<li>The 1.2 site is <a href="http://shorewall.net/1.2/" target="_top">here</a>.</li>
</ul>
Copyright © 2001-2004 Thomas M. Eastep<br>
<div>
<div class="legalnotice">
<p>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 “<span
class="quote"><a
href="file:///vfat/Ursa/Shorewall/Shorewall-Website/GnuCopyright.htm"
target="_self">GNU Free
Documentation License</a></span>”.</p>
</div>
</div>
<div>
<p class="pubdate">2004-07-02<br>
</p>
<hr style="width: 100%; height: 2px;"></div>
<h3>Table of Contents</h3>
<div style="margin-left: 40px;"><a href="#Intro">Introduction to
Shorewall</a><br>
<div style="margin-left: 40px;"><a href="#Glossary">Glossary</a><br>
<a href="#WhatIs">What is Shorewall?</a><br>
<a href="#GettingStarted">Getting Started with Shorewall</a><br>
<a href="#Info">Looking for Information?</a><br>
<a href="#Mandrake">Running Shorewall on Mandrake® with a
two-interface setup?</a><br>
<a href="#License">License</a><br>
</div>
<a href="#News">News</a><a href="#2_0_3b"><br>
</a>
<div style="margin-left: 40px;"><a href="#2_0_3c">Shorewall 2.0.3c</a><br>
<a href="#2_0_3b">Shorewall 2.0.3b</a><br>
<a href="#2_0_3a">Shorewall 2.0.3a</a><br>
<a href="#2_0_3">Shorewall
2.0.3</a><br>
</div>
<a href="#Leaf">Leaf</a><br>
<a href="#Donations">Donations</a><br>
</div>
<h2><a name="Intro"></a>Introduction to Shorewall</h2>
<h3><a name="Glossary"></a>Glossary</h3>
<ul>
<li><a href="http://www.netfilter.org" target="_top">Netfilter</a>
- the
packet filter facility built into the 2.4 and later Linux kernels.</li>
<li>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.</li>
<li>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).</li>
</ul>
<h3><a name="WhatIs"></a>What is Shorewall?</h3>
<div style="margin-left: 40px;">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 with the help of
the iptables utility, Shorewall configures 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
and can thus take advantage of Netfilter's <a
href="http://www.cs.princeton.edu/%7Ejns/security/iptables/iptables_conntrack.html"
target="_top">connection
state tracking
capabilities</a>.<br>
<br>
Shorewall is <span style="text-decoration: underline;">not</span> a
daemon. Once Shorewall has configured Netfilter, it's job is complete.
After that, there is no Shorewall code running although the <a
href="starting_and_stopping_shorewall.htm">/sbin/shorewall
program can be used at any time to monitor the Netfilter firewall</a>.<br>
</div>
<h3><a name="GettingStarted"></a>Getting Started with Shorewall</h3>
<div style="margin-left: 40px;">New to Shorewall? Start by
selecting the <a href="shorewall_quickstart_guide.htm">QuickStart Guide</a>
that most
closely matches your environment and follow the step by step
instructions.<br>
</div>
<h3><a name="Info"></a>Looking for Information?</h3>
<div style="margin-left: 40px;">The <a href="Documentation_Index.html">Documentation
Index</a> is a good place to start as is the Quick Search in the frame
above. </div>
<h3><a name="Mandrake"></a>Running Shorewall on Mandrake® with a
two-interface setup?</h3>
<div style="margin-left: 40px;">If so, the documentation on this
site will not apply directly
to your setup. If you want to use the documentation that you find here,
you will want to consider uninstalling what you have and installing a
setup that matches the documentation on this site. See the <a
href="two-interface.htm">Two-interface QuickStart Guide</a> for
details.<br>
<br>
<span style="font-weight: bold;">Update: </span>I've been
informed by Mandrake Development that this problem has been corrected
in Mandrake 10.0 Final (the problem still exists in the 10.0 Community
release).<br>
</div>
<h3><a name="License"></a>License</h3>
<div style="margin-left: 40px;">This program is free software;
you can redistribute it and/or modify it
under the terms of <a href="http://www.gnu.org/licenses/gpl.html">Version
2 of the GNU General Public License</a> as published by the Free
Software Foundation.<br>
</div>
<p style="margin-left: 40px;">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.</p>
<div style="margin-left: 40px;"> </div>
<p style="margin-left: 40px;">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., 675 Mass Ave, Cambridge, MA 02139, USA</p>
<div style="margin-left: 40px;">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 <a>"GNU Free
Documentation License"</a>. </div>
<p> </p>
<hr style="width: 100%; height: 2px;">
<h2><a name="News"></a>News</h2>
<span style="font-weight: bold;"><a name="2_0_3c"><span
style="font-weight: bold;">7/02/2004 -
Shorewall 2.0.3c<br>
<br>
</span></a></span>Problems Corrected<span style="font-weight: bold;">:<br>
</span>
<ol>
<li> Error messages regarding $RESTOREBASE occur during <span
class="bold"><b>shorewall stop</b></span> </li>
<li> If CLEAR_TC=Yes in <tt class="filename">shorewall.conf</tt>, <span
class="bold"><b>shorewall stop</b></span> fails without removing the
lock file. </li>
</ol>
<span style="font-weight: bold;"><br>
</span><span style="font-weight: bold;"><a name="2_0_3b"></a>6/30/2004
-
Shorewall 2.0.3b and Shorewall 1.4.10g<br>
<br>
</span>Problems Corrected:<br>
<ol>
<li>The security vulnerability fix released in Shorewall 2.0.3a
failed under Slackware 9.1.</li>
<li>The security vulnerability fix released in Shorewall 2.0.3a
failed if mktemp was not installed.<br>
</li>
</ol>
<a name="2_0_3a"></a><span style="font-weight: bold;">6/28/2004 -
Shorewall 2.0.3a and Shorewall 1.4.10f<br>
<br>
</span>Problems Corrected:<br>
<ol>
<li>Javier Fernández-Sanguino Peña has discovered an exploitable
vulnerability in the way that Shorewall handles temporary files and
directories. The vulnerability can allow a non-root user to cause
arbitrary files on the system to be overwritten. LEAF Bering and Bering
uClibc users are generally not at risk due to the fact that LEAF boxes
do not typically allow logins by non-root users. <br>
</li>
<li>(2.0.3a only) A non-empty DEST entry in /etc/shorewall/tcrules
will generate an error and Shorewall fails to start.</li>
</ol>
<div style="margin-left: 40px;">Note:: Slackware users may need the
'functions' file from CVS (STABLE/ project for 1.4.10f and STABLE2/
project for 2.0.3a) to prevent startup errors with these versions
installed. These updatged files are also available from the Errata (<a
href="errata.htm">2.0,</a> <a href="1.4/errata.htm">1.4</a>).<br>
<br>
</div>
<a name="2_0_3"></a><span style="font-weight: bold;">6/23/2004 -
Shorewall 2.0.3<br>
<br>
</span>Problems Corrected:<br>
<ol>
<li>The 'firewall' script is not purging temporary restore files in
/var/lib/shorewall. These files have names of the form "restore-nnnnn".</li>
<li>The /var/lib/shorewall/restore script did not load the kernel
modules specified in /etc/shorewall/modules.</li>
<li>Specifying a null common action in /etc/shorewall/actions (e.g.,
:REJECT) results in a startup error.</li>
<li>If /var/lib/shorewall does not exist, shorewall start fails.</li>
<li>DNAT rules with a dynamic source zone don't work properly. When
used, these rules cause the rule to be checked against ALL input, not
just input from the designated zone.</li>
<li>The install.sh script reported installing some files in
/etc/shorewall when the files were actually installed in
/usr/share/shorewall.</li>
<li>Shorewall checks netfilter capabilities before loading kernel
modules. Hence if kernel module autoloading isn't enabled, the
capabilities will be misdetected.</li>
<li>The 'newnotsyn' option in /etc/shorewall/hosts has no effect.</li>
<li>The file /etc/init.d/shorewall now gets proper ownership when the
RPM is built by a non-root user.</li>
<li>Rules that specify bridge ports in both the SOURCE and DEST
columns no longer cause "shorewall start" to fail.</li>
<li>Comments in the rules file have been added to advise users that
"all" in the SOURCE or DEST column does not affect intra-zone traffic.</li>
<li>With BLACKLISTNEWONLY=Yes, ICMP packets with state INVALID are
now passed through the blacklisting chains. Without this change, it is
not possible to blacklist hosts that are mounting certain types of
ICMP-based DOS attacks.</li>
</ol>
Issues when migrating from Shorewall 2.0.2 to Shorewall 2.0.3:<br>
<ol>
<li>The 'dropNonSyn' standard builtin action has been replaced with
the 'dropNotSyn' standard builtin action. The old name can still be
used but will generate a warning.</li>
</ol>
New Features:<br>
<ol>
<li>Shorewall now supports multiple saved configurations.</li>
<ol>
<li>The default saved configuration (restore script) in
/var/lib/shorewall is now specified using the RESTOREFILE option in
shorewall.conf. If this variable isn't set then to maintain backward
compatibility, 'restore' is assumed.<br>
<br>
The value of RESTOREFILE must be a simple file name; no slashes ("/")
may be included.<br>
</li>
<li>The "save" command has been extended to be able to specify the
name of a saved configuration.<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; shorewall
save [ &lt;file name&gt; ]<br>
<br>
The current state is saved to /var/lib/shorewall/&lt;file name&gt;. If
no &lt;file name&gt; is given, the configuration is saved to the file
determined by the RESTOREFILE setting.</li>
<li>The "restore" command has been extended to be able to specify
the name of a saved configuration:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; shorewall
restore [ &lt;file name&gt; ]<br>
<br>
The firewall state is restored from /var/lib/shorewall/&lt;file
name&gt;. If no &lt;file name&gt; is given, the firewall state is
restored from the file determined by the RESTOREFILE setting.</li>
<li>The "forget" command has changed. Previously, the command
unconditionally removed the /var/lib/shorewall/save file which records
the current dynamic blacklist. The "forget" command now leaves that
file alone.<br>
<br>
Also, the "forget" command has been extended to be able to specify the
name of a saved configuration:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
shorewall forget [ &lt;file name&gt; ]<br>
<br>
The file /var/lib/shorewall/&lt;file name&gt; is removed. If no
&lt;file name&gt; is given, the file determined by the RESTOREFILE
setting is removed.</li>
<li>The "shorewall -f start" command restores the state from the
file determined by the RESTOREFILE setting.</li>
</ol>
<li>"!" is now allowed in accounting rules.</li>
<li>Interface names appearing within the configuration are now
verified. Interface names must match the name of an entry in
/etc/shorewall/interfaces (or if bridging is enabled, they must match
the name of an entry in /etc/shorewall/interfaces or the name of a
bridge port appearing in /etc/shorewall/hosts).</li>
<li>A new 'rejNotSyn' built-in standard action has been added. This
action responds to "New not SYN" packets with an RST.<br>
<br>
The 'dropNonSyn' action has been superceded by the new 'dropNotSyn'
action. The old name will be accepted until the next major release of
Shorewall but will generate a warning.<br>
<br>
Several new logging actions involving "New not SYN" packets have been
added:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; logNewNotSyn&nbsp; -- logs
the packet with disposition = LOG<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; dLogNewNotSyn -- logs the
packet with disposition = DROP<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; rLogNewNotSyn -- logs the
packet with disposition = REJECT<br>
<br>
The packets are logged at the log level specified in the LOGNEWNOTSYN
option in shorewall.conf. If than option is empty or not specified,
then 'info' is assumed.<br>
<br>
Examples (In all cases, set NEWNOTSYN=Yes in shorewall.conf):</li>
<ol>
<li>To simulate the behavior of NEWNOTSYN=No:
<ol>
<li>Add 'NoNewNotSyn' to /etc/shorewall/actions.</li>
<li>Create /etc/shorewall/action.NoNewNotSyn containing:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
dLogNotSyn<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
dropNotSyn<br>
<br>
</li>
<li>Early in your rules file, place:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
NoNewNotSyn&nbsp;&nbsp; all&nbsp;&nbsp; all&nbsp;&nbsp;&nbsp;&nbsp; tcp<br>
<br>
</li>
</ol>
</li>
<li>Drop 'New not SYN' packets from the net only. Don't log them:</li>
<ol>
<li>Early in your rules file, place:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
dropNotSyn&nbsp;&nbsp;&nbsp;
net&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; all&nbsp;&nbsp; tcp<br>
<br>
</li>
</ol>
</ol>
<li>Slackware users no longer have to modify the install.sh script
before installation. Tuomo Soini has provided a change that allows the
INIT and FIREWALL variables to be specified outside the script as in:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; DEST=/etc/rc.d INIT=rc.firewall
./install.sh<br>
</li>
</ol>
<ol>
</ol>
<p><a href="News.htm">More News</a></p>
<hr style="width: 100%; height: 2px;">
<h2><a name="Leaf"></a>Leaf<br>
</h2>
<p><a href="http://leaf.sourceforge.net" target="_top"><img
alt="(Leaf Logo)"
style="border: 0px solid ; height: 36px; width: 49px;"
src="images/leaflogo.gif" title=""></a> 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.<br>
</p>
<div>
<div style="text-align: center;"> </div>
</div>
<hr style="width: 100%; height: 2px;">
<h2><a name="Donations"></a>Donations
</h2>
<p style="text-align: left;"> </p>
<p style="text-align: left;"><big><a href="http://www.alz.org"
target="_top"><img src="images/alz_logo2.gif" title=""
alt="(Alzheimer's Association Logo)"
style="border: 0px solid ; width: 300px; height: 60px;" align="left"></a></big></p>
<h2><big><a href="http://www.starlight.org" target="_top"><img
src="images/newlog.gif" title="" alt="(Starlight Foundation Logo)"
style="border: 0px solid ; width: 59px; height: 102px;" align="left"></a></big></h2>
<p style="text-align: left;"><big>Shorewall
is free but
if you
try it and find it useful,
please consider making a donation to the <a href="http://www.alz.org/"
target="_top">Alzheimer's Association</a> or to the <a
href="http://www.starlight.org" target="_top">Starlight Children's
Foundation</a>.<br>
</big></p>
<p style="text-align: left;"><big>Thanks<br>
<br>
</big></p>
<p style="text-align: left;"><big><br>
</big> </p>
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