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<title>Shoreline Firewall (Shorewall) 1.4</title>
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valign="middle" align="center"><a href="http://www.cityofshoreline.com">
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<h2>What is it?</h2>
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<p>The Shoreline Firewall, more commonly known as "Shorewall", is a
<a href="http://www.netfilter.org">Netfilter</a> (iptables) based firewall
that can be used on a dedicated firewall system, a multi-function
gateway/router/server or on a standalone GNU/Linux system.</p>
<p>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>
<br>
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.<br>
<br>
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>
<p><a href="copyright.htm">Copyright 2001, 2002, 2003 Thomas M. Eastep</a></p>
<h2>This is the Shorewall 1.4 Web Site</h2>
The information on this site applies only to 1.4.x releases of
Shorewall. For older versions:<br>
<ul>
<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>.<br>
</li>
</ul>
<h2>Getting Started with Shorewall</h2>
New to Shorewall? Start by
selecting the <a href="shorewall_quickstart_guide.htm">QuickStart
Guide</a> that most closely match your environment
and follow the step by step instructions.<br>
<h2>Looking for Information?</h2>
The <a
href="shorewall_quickstart_guide.htm#Documentation">Documentation
Index</a> is a good place to start as is the Quick Search to your right.
<h2>Running Shorewall on Mandrake with a two-interface setup?</h2>
If so, the documentation<b> </b>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>
<h2>News</h2>
<p><b>8/5/2003 - Shorewall-1.4.6b</b><b> <img border="0"
src="images/new10.gif" width="28" height="12" alt="(New)">
<br>
</b></p>
<b>Problems Corrected since version 1.4.6:</b><br>
<ol>
<li>Previously, if TC_ENABLED is set to yes in shorewall.conf then
Shorewall would fail to start with the error "ERROR: <20>Traffic Control
requires Mangle"; that problem has been corrected.</li>
<li>Corrected handling of MAC addresses in the SOURCE column of the
tcrules file. Previously, these addresses resulted in an invalid iptables
command.</li>
<li>The "shorewall stop" command is now disabled when /etc/shorewall/startup_disabled
exists. This prevents people from shooting themselves in the foot prior to
having configured Shorewall.</li>
<li>A change introduced in version 1.4.6 caused error messages during
"shorewall [re]start" when ADD_IP_ALIASES=Yes and ip addresses were being
added to a PPP interface; the addresses were successfully added in spite
of the messages.<br>
<EFBFBD><EFBFBD> <br>
The firewall script has been modified to eliminate the error messages.<br>
</li>
</ol>
<p><b>7/31/2003 - Snapshot 1.4.6_20030731</b><b> </b></p>
<blockquote>
<p><a href="http://shorewall.net/pub/shorewall/Snapshots/">http://shorewall.net/pub/shorewall/Snapshots/</a><br>
<a href="ftp://shorewall.net/pub/shorewall/Snapshots/"
target="_top">ftp://shorewall.net/pub/shorewall/Snapshots/</a></p>
</blockquote>
<b>Problems Corrected since version 1.4.6</b><br>
<ol>
<li>Corrected problem in 1.4.6 where the MANGLE_ENABLED variable
was being tested before it was set.</li>
<li>Corrected handling of MAC addresses in the SOURCE column of
the tcrules file. Previously, these addresses resulted in an invalid iptables
command.<br>
</li>
</ol>
<b>Migration Issues:</b><br>
<ol>
<li>Once you have installed this version of Shorewall, you must
restart Shorewall before you may use the 'drop', 'reject', 'allow' or 'save'
commands.</li>
<li>To maintain strict compatibility with previous versions, current
uses of "shorewall drop" and "shorewall reject" should be replaced with "shorewall
dropall" and "shorewall rejectall" </li>
</ol>
<b>New Features:</b><br>
<ol>
<li>Shorewall now creates a dynamic blacklisting chain for each
interface defined in /etc/shorewall/interfaces. The 'drop' and 'reject'
commands use the routing table to determine which of these chains is to
be used for blacklisting the specified IP address(es).<br>
<br>
Two new commands ('dropall' and 'rejectall') have been introduced that
do what 'drop' and 'reject' used to do; namely, when an address is blacklisted
using these new commands, it will be blacklisted on all of your firewall's
interfaces.</li>
<li>Thanks to Steve Herber, the 'help' command can now give command-specific
help (e.g., shorewall help &lt;command&gt;).</li>
<li>A new option "ADMINISABSENTMINDED" has been added to /etc/shorewall/shorewall.conf.
This option has a default value of "No" for existing users which causes Shorewall's
'stopped' state <20>to continue as it has been; namely, in the stopped state
only traffic to/from hosts listed in /etc/shorewall/routestopped is accepted.<br>
<br>
With ADMINISABSENTMINDED=Yes (the default for new installs), in addition
to traffic to/from the hosts listed in /etc/shorewall/routestopped, Shorewall
will allow:<br>
<br>
<20><> a) All traffic originating from the firewall itself; and<br>
<20><> b) All traffic that is part of or related to an already-existing connection.<br>
<br>
<20>In particular, with ADMINISABSENTMINDED=Yes, a "shorewall stop" entered
through an ssh session will not kill the session.<br>
<br>
<20>Note though that even with ADMINISABSENTMINDED=Yes, it is still possible
for people to shoot themselves in the foot.<br>
<br>
<20>Example:<br>
<br>
<20>/etc/shorewall/nat:<br>
<br>
<20> <20> <20>206.124.146.178<EFBFBD><EFBFBD><EFBFBD> eth0:0<><30><EFBFBD> 192.168.1.5<EFBFBD><EFBFBD><EFBFBD> <br>
<br>
<20>/etc/shorewall/rules:<br>
<br>
<20><> ACCEPT<50><54><EFBFBD> net<65><74><EFBFBD> loc:192.168.1.5<EFBFBD><EFBFBD><EFBFBD> tcp<63><70><EFBFBD> 22<br>
<20><> ACCEPT<50><54><EFBFBD> loc<6F><63><EFBFBD> fw<66><77><EFBFBD> <20><><EFBFBD> tcp<63><70><EFBFBD> 22<br>
<br>
From a remote system, I ssh to 206.124.146.178 which establishes an SSH
connection with local system 192.168.1.5. I then create a second SSH connection
from that computer to the firewall and confidently type "shorewall stop".
As part of its stop processing, Shorewall removes eth0:0 which kills my SSH
connection to 192.168.1.5!!!<br>
</li>
</ol>
<p><b>7/22/2003 - Shorewall-1.4.6a</b><b><br>
</b></p>
<b>Problems Corrected:</b><br>
<ol>
<li>Previously, if TC_ENABLED is set to yes in shorewall.conf
then Shorewall would fail to start with the error "ERROR: <20>Traffic Control
requires Mangle"; that problem has been corrected.</li>
</ol>
<p><b>7/20/2003 - Shorewall-1.4.6</b><b> </b><br>
</p>
<blockquote> </blockquote>
<p><b>Problems Corrected:</b><br>
</p>
<ol>
<li>A problem seen on RH7.3 systems where Shorewall
encountered start errors when started using the "service" mechanism
has been worked around.<br>
<br>
</li>
<li>Where a list of IP addresses appears in the
DEST column of a DNAT[-] rule, Shorewall incorrectly created multiple
DNAT rules in the nat table (one for each element in the list). Shorewall
now correctly creates a single DNAT rule with multiple "--to-destination"
clauses.<br>
<br>
</li>
<li>Corrected a problem in Beta 1 where DNS names
containing a "-" were mis-handled when they appeared in the DEST
column of a rule.<br>
<br>
</li>
<li>A number of problems with rule parsing have been
corrected. Corrections involve the handling of "z1!z2" in the SOURCE
column as well as lists in the ORIGINAL DESTINATION column.<br>
<br>
</li>
<li>The message "Adding rules for DHCP" is now suppressed
if there are no DHCP rules to add.<br>
</li>
</ol>
<p><b>Migration Issues:</b><br>
</p>
<ol>
<li>In earlier versions, an undocumented feature
allowed entries in the host file as follows:<br>
<br>
<20> <20> z<><7A><EFBFBD> eth1:192.168.1.0/24,eth2:192.168.2.0/24<br>
<br>
This capability was never documented and has been removed
in 1.4.6 to allow entries of the following format:<br>
<br>
<20> <20> z<><7A> eth1:192.168.1.0/24,192.168.2.0/24<br>
<br>
</li>
<li>The NAT_ENABLED, MANGLE_ENABLED and MULTIPORT
options have been removed from /etc/shorewall/shorewall.conf. These
capabilities are now automatically detected by Shorewall (see below).<br>
</li>
</ol>
<p><b>New Features:</b><br>
</p>
<ol>
<li>A 'newnotsyn' interface option has been added.
This option may be specified in /etc/shorewall/interfaces and overrides
the setting NEWNOTSYN=No for packets arriving on the associated interface.<br>
<br>
</li>
<li>The means for specifying a range of IP addresses
in /etc/shorewall/masq to use for SNAT is now documented. ADD_SNAT_ALIASES=Yes
is enabled for address ranges.<br>
<br>
</li>
<li>Shorewall can now add IP addresses to subnets
other than the first one on an interface.<br>
<br>
</li>
<li>DNAT[-] rules may now be used to load balance
(round-robin) over a set of servers. Servers may be specified in
a range of addresses given as &lt;first address&gt;-&lt;last address&gt;.<br>
<br>
Example:<br>
<br>
<20> <20> DNAT net loc:192.168.10.2-192.168.10.5 tcp 80<br>
<br>
</li>
<li>The NAT_ENABLED, MANGLE_ENABLED and MULTIPORT
configuration options have been removed and have been replaced by
code that detects whether these capabilities are present in the current
kernel. The output of the start, restart and check commands have been
enhanced to report the outcome:<br>
<br>
Shorewall has detected the following iptables/netfilter
capabilities:<br>
<20> <20>NAT: Available<br>
<20> <20>Packet Mangling: Available<br>
<20> <20>Multi-port Match: Available<br>
Verifying Configuration...<br>
<br>
</li>
<li>Support for the Connection Tracking Match Extension
has been added. This extension is available in recent kernel/iptables
releases and allows for rules which match against elements in netfilter's
connection tracking table. Shorewall automatically detects the availability
of this extension and reports its availability in the output of the
start, restart and check commands.<br>
<br>
Shorewall has detected the following iptables/netfilter
capabilities:<br>
<20> <20>NAT: Available<br>
<20> <20>Packet Mangling: Available<br>
<20> <20>Multi-port Match: Available<br>
<20> <20>Connection Tracking Match: Available<br>
Verifying Configuration...<br>
<br>
If this extension is available, the ruleset generated
by Shorewall is changed in the following ways:</li>
<ul>
<li>To handle 'norfc1918' filtering, Shorewall
will not create chains in the mangle table but will rather do all
'norfc1918' filtering in the filter table (rfc1918 chain).</li>
<li>Recall that Shorewall DNAT rules generate
two netfilter rules; one in the nat table and one in the filter
table. If the Connection Tracking Match Extension is available, the
rule in the filter table is extended to check that the original destination
address was the same as specified (or defaulted to) in the DNAT rule.<br>
<br>
</li>
</ul>
<li>The shell used to interpret the firewall script
(/usr/share/shorewall/firewall) may now be specified using the SHOREWALL_SHELL
parameter in shorewall.conf.<br>
<br>
</li>
<li>An 'ipcalc' command has been added to /sbin/shorewall.<br>
<br>
<20><><EFBFBD><EFBFBD><EFBFBD> ipcalc [ &lt;address&gt; &lt;netmask&gt; | &lt;address&gt;/&lt;vlsm&gt;
]<br>
<br>
Examples:<br>
<br>
<20><><EFBFBD><EFBFBD><EFBFBD> [root@wookie root]# shorewall ipcalc 192.168.1.0/24<br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> CIDR=192.168.1.0/24<br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> NETMASK=255.255.255.0<br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> NETWORK=192.168.1.0<br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> BROADCAST=192.168.1.255<br>
<20><><EFBFBD><EFBFBD><EFBFBD> [root@wookie root]#<br>
<br>
<20><><EFBFBD><EFBFBD><EFBFBD> [root@wookie root]# shorewall ipcalc 192.168.1.0
255.255.255.0<br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> CIDR=192.168.1.0/24<br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> NETMASK=255.255.255.0<br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> NETWORK=192.168.1.0<br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> BROADCAST=192.168.1.255<br>
<20><><EFBFBD><EFBFBD><EFBFBD> [root@wookie root]#<br>
<br>
Warning:<br>
<br>
If your shell only supports 32-bit signed arithmatic (ash
or dash), then the ipcalc command produces incorrect information for
IP addresses 128.0.0.0-1 and for /1 networks. Bash should produce correct
information for all valid IP addresses.<br>
<br>
</li>
<li>An 'iprange' command has been added to /sbin/shorewall.
<br>
<br>
<20><><EFBFBD><EFBFBD><EFBFBD> iprange &lt;address&gt;-&lt;address&gt;<br>
<br>
This command decomposes a range of IP addressses into a
list of network and host addresses. The command can be useful if you
need to construct an efficient set of rules that accept connections from
a range of network addresses.<br>
<br>
Note: If your shell only supports 32-bit signed arithmetic
(ash or dash) then the range may not span 128.0.0.0.<br>
<br>
Example:<br>
<br>
<20><><EFBFBD><EFBFBD><EFBFBD> [root@gateway root]# shorewall iprange 192.168.1.4-192.168.12.9<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.1.4/30<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.1.8/29<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.1.16/28<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.1.32/27<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.1.64/26<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.1.128/25<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.2.0/23<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.4.0/22<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.8.0/22<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.12.0/29<br>
<20><><EFBFBD><EFBFBD><EFBFBD> 192.168.12.8/31<br>
<20><><EFBFBD><EFBFBD><EFBFBD> [root@gateway root]#<br>
<br>
</li>
<li>A list of host/net addresses is now allowed
in an entry in /etc/shorewall/hosts.<br>
<br>
Example:<br>
<br>
<20><><EFBFBD> foo<6F><6F><EFBFBD> eth1:192.168.1.0/24,192.168.2.0/24<br>
<br>
</li>
<li>The "shorewall check" command now includes the chain
name when printing the applicable policy for each pair of zones.<br>
<20><br>
<20><><EFBFBD> Example:<br>
<20><br>
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> Policy for dmz to net is REJECT using chain all2all<br>
<20><br>
This means that the policy for connections from the dmz to the internet
is REJECT and the applicable entry in the /etc/shorewall/policy was the
all-&gt;all policy.<br>
<br>
</li>
<li>Support for the 2.6 Kernel series has been added.<br>
</li>
</ol>
<p><b></b></p>
<ol>
</ol>
<p><a href="News.htm">More News</a></p>
<p> <a href="http://leaf.sourceforge.net" target="_top"><img
border="0" src="images/leaflogo.gif" width="49" height="36"
alt="(Leaf Logo)">
</a>Jacques Nilo and
Eric Wolzak have a LEAF (router/firewall/gateway
on a floppy, CD or compact flash)
distribution called <i>Bering</i>
that features Shorewall-1.4.2 and
Kernel-2.4.20. You can find their
work at: <a
href="http://leaf.sourceforge.net/devel/jnilo"> http://leaf.sourceforge.net/devel/jnilo<br>
</a></p>
<b>Congratulations to Jacques
and Eric on the recent release of Bering 1.2!!! </b><br>
<h2><a name="Donations"></a>Donations</h2>
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<p align="center"><a href="http://www.starlight.org"> <img
border="4" src="images/newlog.gif" width="57" height="100" align="left"
hspace="10" alt="(Starlight Logo)">
</a></p>
<p align="center"><font size="4" color="#ffffff"><br>
<font size="+2"> Shorewall is free but if
you try it and find it useful, please consider making a donation
to <a href="http://www.starlight.org"><font
color="#ffffff">Starlight Children's Foundation.</font></a>
Thanks!</font></font></p>
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<p><font size="2">Updated 8/5/2003 - <a href="support.htm">Tom Eastep</a></font>
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