2002-08-13 22:45:21 +02:00
|
|
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
|
|
|
|
<html>
|
|
|
|
|
|
<head>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<meta http-equiv="Content-Type"
|
|
|
|
|
|
content="text/html; charset=windows-1252">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-08-13 22:45:21 +02:00
|
|
|
|
<meta name="GENERATOR" content="Microsoft FrontPage 5.0">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<meta name="ProgId" content="FrontPage.Editor.Document">
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<title>Shorewall 1.4 Documentation</title>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<base target="_self">
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<meta name="Microsoft Theme" content="none, default">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<meta name="Microsoft Border" content="none, default">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<meta name="author" content="Tom Eastep">
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</head>
|
|
|
|
|
|
<body>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="0" cellpadding="0" cellspacing="0"
|
|
|
|
|
|
style="border-collapse: collapse;" width="100%" id="AutoNumber4"
|
|
|
|
|
|
bgcolor="#400169" height="90">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td width="100%">
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<h1 align="center"><font color="#ffffff">Shorewall 1.4 Reference</font></h1>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<h2 align="center">This documentation is intended primarily for reference.
|
|
|
|
|
|
Step-by-step instructions for configuring Shorewall
|
2003-03-22 01:25:40 +01:00
|
|
|
|
in common setups may be found in the <a
|
2002-12-28 16:38:03 +01:00
|
|
|
|
href="shorewall_quickstart_guide.htm">QuickStart Guides</a>.</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<h2>Components</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>Shorewall consists of the following components: </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b><a href="#Variables">params</a></b>
|
|
|
|
|
|
-- a parameter file installed in /etc/shorewall that can
|
|
|
|
|
|
be used to establish the values of shell variables for use
|
2003-03-22 01:25:40 +01:00
|
|
|
|
in other files.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> <a href="#Conf">shorewall.conf</a></b>
|
|
|
|
|
|
-- a parameter file installed in /etc/shorewall
|
|
|
|
|
|
that is used to set several firewall parameters.</li>
|
|
|
|
|
|
<li><b> <a href="#Zones">zones</a></b>
|
|
|
|
|
|
- a parameter file installed in /etc/shorewall that defines
|
2003-03-22 01:25:40 +01:00
|
|
|
|
a network partitioning into "zones"</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> <a href="#Policy">policy</a></b>
|
|
|
|
|
|
-- a parameter file installed in /etc/shorewall/ that establishes
|
|
|
|
|
|
overall firewall policy.</li>
|
|
|
|
|
|
<li><b> <a href="#Rules">rules</a>
|
|
|
|
|
|
</b> -- a parameter file installed in /etc/shorewall and
|
|
|
|
|
|
used to express firewall rules that are exceptions to
|
2003-03-22 01:25:40 +01:00
|
|
|
|
the high-level policies established in /etc/shorewall/policy.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b><a href="#Blacklist">blacklist</a>
|
|
|
|
|
|
-- </b>a parameter file installed in /etc/shorewall and
|
2003-03-22 01:25:40 +01:00
|
|
|
|
used to list blacklisted IP/subnet/MAC addresses.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b><a href="#ECN">ecn</a></b> -- a parameter file installed in
|
|
|
|
|
|
/etc/shorewall and used to selectively disable Explicit Congestion Notification
|
|
|
|
|
|
(ECN - RFC 3168).<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b> functions</b> -- a set of
|
|
|
|
|
|
shell functions used by both the firewall and shorewall
|
|
|
|
|
|
shell programs. Installed in /etc/shorewall prior to version
|
|
|
|
|
|
1.3.2, in /var/lib/shorewall in version s 1.3.2-1.3.8 and in /usr/lib/shorewall
|
2003-03-22 01:25:40 +01:00
|
|
|
|
in later versions.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> <a href="#modules">modules</a></b>
|
|
|
|
|
|
-- a parameter file installed in /etc/shorewall and that
|
|
|
|
|
|
specifies kernel modules and their parameters. Shorewall will
|
2003-03-22 01:25:40 +01:00
|
|
|
|
automatically load the modules specified in this file.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><a
|
|
|
|
|
|
href="#TOS"><b> tos</b> </a>-- a parameter file installed
|
|
|
|
|
|
in /etc/shorewall that is used to specify how the Type of
|
|
|
|
|
|
Service (TOS) field in packets is to be set.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b><a href="#Scripts">common.def</a></b>
|
|
|
|
|
|
-- a parameter file installed in in /etc/shorewall that
|
|
|
|
|
|
defines firewall-wide rules that are applied before a DROP
|
2003-03-22 01:25:40 +01:00
|
|
|
|
or REJECT policy is applied.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> <a href="#Interfaces">interfaces</a>
|
|
|
|
|
|
</b> -- a parameter file installed in /etc/shorewall/
|
|
|
|
|
|
and used to describe the interfaces on the firewall system.</li>
|
|
|
|
|
|
<li><a href="#Hosts"><b> hosts</b>
|
|
|
|
|
|
</a>-- a parameter file installed in /etc/shorewall/ and
|
|
|
|
|
|
used to describe individual hosts or subnetworks in
|
2003-03-22 01:25:40 +01:00
|
|
|
|
zones.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b><a href="#Maclist">maclist</a> </b>--
|
|
|
|
|
|
a parameter file installed in /etc/shorewall and used to verify
|
2003-03-22 01:25:40 +01:00
|
|
|
|
the MAC address (and possibly also the IP address(es)) of devices.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b> <a href="#Masq">masq</a></b>
|
|
|
|
|
|
- This file also describes IP masquerading under Shorewall
|
2003-03-22 01:25:40 +01:00
|
|
|
|
and is installed in /etc/shorewall.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b><a
|
|
|
|
|
|
href="shorewall_firewall_structure.htm">firewall</a></b> -- a shell
|
|
|
|
|
|
program that reads the configuration files in /etc/shorewall
|
|
|
|
|
|
and configures your firewall. This file is installed
|
|
|
|
|
|
in your init.d directory (/etc/rc.d/init.d ) where it
|
|
|
|
|
|
is renamed <i>shorewall.</i> /etc/shorewall/firewall (/var/lib/shorewall/firewall
|
|
|
|
|
|
in versions 1.3.2-1.3.8 and /usr/lib/shorewall/firewall in 1.3.9
|
2003-03-22 01:25:40 +01:00
|
|
|
|
and later) is a symbolic link to this program.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> <a href="#NAT">nat</a></b>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
-- a parameter file in /etc/shorewall used to define <a
|
2003-02-20 00:21:55 +01:00
|
|
|
|
href="#NAT"> static NAT</a> .</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> <a href="#ProxyArp">proxyarp</a></b>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
-- a parameter file in /etc/shorewall used to define <a
|
2003-01-14 18:18:42 +01:00
|
|
|
|
href="#ProxyArp"> Proxy Arp</a> .</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b><a href="#rfc1918">rfc1918</a></b>
|
|
|
|
|
|
-- a parameter file in /etc/shorewall used to define the
|
|
|
|
|
|
treatment of packets under the <a href="#Interfaces">norfc1918
|
|
|
|
|
|
interface option</a>.</li>
|
|
|
|
|
|
<li><b><a href="#Routestopped">routestopped</a></b>
|
|
|
|
|
|
-- a parameter file in /etc/shorewall used to define those
|
2003-03-22 01:25:40 +01:00
|
|
|
|
hosts that can access the firewall when Shorewall is stopped.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><a
|
|
|
|
|
|
href="traffic_shaping.htm#tcrules"><b>tcrules</b> </a>-- a
|
|
|
|
|
|
parameter file in /etc/shorewall used to define rules for classifying
|
2003-03-22 01:25:40 +01:00
|
|
|
|
packets for <a href="traffic_shaping.htm">Traffic Shaping/Control</a>.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> <a href="#Tunnels">tunnels</a></b>
|
|
|
|
|
|
-- a parameter file in /etc/shorewall used to define IPSec
|
|
|
|
|
|
tunnels.</li>
|
|
|
|
|
|
<li><b> <a href="#Starting">shorewall</a>
|
|
|
|
|
|
</b> -- a shell program (requiring a Bourne shell or
|
|
|
|
|
|
derivative) used to control and monitor the firewall.
|
|
|
|
|
|
This should be placed in /sbin or in /usr/sbin (the
|
|
|
|
|
|
install.sh script and the rpm install this file in /sbin).</li>
|
|
|
|
|
|
<li><b> version</b> -- a file created
|
|
|
|
|
|
in /etc/shorewall/ (/var/lib/shorewall in version
|
|
|
|
|
|
1.3.2-1.3.8 and /usr/lib/shorewall beginning in version 1.3.9)
|
|
|
|
|
|
that describes the version of Shorewall installed
|
2003-03-22 01:25:40 +01:00
|
|
|
|
on your system.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<h2><a name="Variables"></a> /etc/shorewall/params</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>You may use the file /etc/shorewall/params file to set shell variables
|
|
|
|
|
|
that you can then use in some of the other configuration
|
2003-03-22 01:25:40 +01:00
|
|
|
|
files.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>It is suggested that variable names begin with an upper case letter<font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
size="1"> </font>to distinguish them from variables used internally
|
2003-03-22 01:25:40 +01:00
|
|
|
|
within the Shorewall programs</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>Example:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-01-22 01:37:23 +01:00
|
|
|
|
<pre><font face="Courier"> NET_IF=eth0<br> NET_BCAST=130.252.100.255<br> NET_OPTIONS=blacklist,norfc1918</font></pre>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>Example (/etc/shorewall/interfaces record):</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<pre> <font face="Courier">net $NET_IF $NET_BCAST $NET_OPTIONS</font></pre>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>The result will be the same as if the record had been written</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-01-22 01:37:23 +01:00
|
|
|
|
<pre> <font face="Courier">net eth0 130.252.100.255 blacklist,norfc1918</font></pre>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Variables may be used anywhere in the other configuration
|
2003-03-22 01:25:40 +01:00
|
|
|
|
files.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<h2><b><a name="Zones"></a> </b>/etc/shorewall/zones</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>This file is used to define the network zones. There is one entry
|
|
|
|
|
|
in /etc/shorewall/zones for each zone; Columns in an entry
|
2003-03-22 01:25:40 +01:00
|
|
|
|
are:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> ZONE</b> - short name for
|
|
|
|
|
|
the zone. The name should be 5 characters or less in length
|
|
|
|
|
|
and consist of lower-case letters or numbers. Short names must
|
|
|
|
|
|
begin with a letter and the name assigned to the firewall
|
|
|
|
|
|
is reserved for use by Shorewall itself. Note that the output
|
|
|
|
|
|
produced by iptables is much easier to read if you select
|
|
|
|
|
|
short names that are three characters or less in length. The
|
|
|
|
|
|
name "all" may not be used as a zone name nor may the zone name
|
|
|
|
|
|
assigned to the firewall itself via the FW variable in <a
|
|
|
|
|
|
href="#Conf">/etc/shorewall/shorewall.conf</a>.</li>
|
|
|
|
|
|
<li><b> DISPLAY</b> - The name of
|
|
|
|
|
|
the zone as displayed during Shorewall startup.</li>
|
|
|
|
|
|
<li><b> COMMENTS</b> - Any comments
|
|
|
|
|
|
that you want to make about the zone. Shorewall ignores
|
2003-03-22 01:25:40 +01:00
|
|
|
|
these comments.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>The /etc/shorewall/zones file released with Shorewall is as follows:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" style="border-collapse: collapse;" cellpadding="2">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> DISPLAY</b></td>
|
|
|
|
|
|
<td><b> COMMENTS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>Net</td>
|
|
|
|
|
|
<td>Internet</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>Local</td>
|
|
|
|
|
|
<td>Local networks</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>dmz</td>
|
|
|
|
|
|
<td>DMZ</td>
|
|
|
|
|
|
<td>Demilitarized zone</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>You may add, delete and modify entries in the /etc/shorewall/zones file
|
2003-03-22 01:25:40 +01:00
|
|
|
|
as desired so long as you have at least one zone defined.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p><b><font size="5" color="#ff0000"> Warning 1: </font><font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
color="#ff0000"> If you rename or delete a zone, you should perform "shorewall
|
|
|
|
|
|
stop; shorewall start" to install the change rather than
|
2003-03-22 01:25:40 +01:00
|
|
|
|
"shorewall restart".</font></b></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p><b><font size="5" color="#ff0000">Warning 2: </font><font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
color="#ff0000">The order of entries in the /etc/shorewall/zones file is
|
2003-03-22 01:25:40 +01:00
|
|
|
|
significant <a href="#Nested">in some cases</a>.</font></b></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<h2><font color="#660066"><a name="Interfaces"></a> </font>/etc/shorewall/interfaces</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>This file is used to tell the firewall which of your firewall's network
|
|
|
|
|
|
interfaces are connected to which zone. There will be one
|
|
|
|
|
|
entry in /etc/shorewall/interfaces for each of your interfaces.
|
2003-03-22 01:25:40 +01:00
|
|
|
|
Columns in an entry are:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> ZONE</b> - A zone defined
|
|
|
|
|
|
in the <a href="#Zones">/etc/shorewall/zones</a> file
|
|
|
|
|
|
or "-". If you specify "-", you must use the <a
|
|
|
|
|
|
href="#Hosts"> /etc/shorewall/hosts</a> file to define
|
|
|
|
|
|
the zones accessed via this interface.</li>
|
|
|
|
|
|
<li><b> INTERFACE</b> - the name of
|
|
|
|
|
|
the interface (examples: eth0, ppp0, ipsec+). Each interface
|
2003-03-22 01:25:40 +01:00
|
|
|
|
can be listed on only one record in this file. <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
color="#ff0000"><b>D</b><b>O NOT INCLUDE THE LOOPBACK INTERFACE
|
2003-03-22 01:25:40 +01:00
|
|
|
|
(lo) IN THIS FILE!!!</b></font></li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> BROADCAST</b> - the broadcast
|
|
|
|
|
|
address(es) for the sub-network(s) attached to the interface.
|
|
|
|
|
|
This should be left empty for P-T-P interfaces (ppp*, ippp*);
|
|
|
|
|
|
if you need to specify options for such an interface, enter
|
|
|
|
|
|
"-" in this column. If you supply the special value "detect" in
|
|
|
|
|
|
this column, the firewall will automatically determine the broadcast
|
|
|
|
|
|
address. In order to use "detect":
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>the
|
2003-03-22 01:25:40 +01:00
|
|
|
|
interface must be up before you start your firewall</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>the interface must only be attached
|
|
|
|
|
|
to a single sub-network (i.e., there must have a single broadcast
|
2003-03-22 01:25:40 +01:00
|
|
|
|
address). </li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b> OPTIONS</b> - a comma-separated
|
|
|
|
|
|
list of options. Possible options include:
|
|
|
|
|
|
<p> <b>tcpflags </b>(added in version 1.3.11) - This option causes
|
|
|
|
|
|
Shorewall to make sanity checks on the header flags in TCP packets arriving
|
|
|
|
|
|
on this interface. Checks include Null flags, SYN+FIN, SYN+RST and FIN+URG+PSH;
|
|
|
|
|
|
these flag combinations are typically used for "silent" port scans. Packets
|
|
|
|
|
|
failing these checks are logged according to the TCP_FLAGS_LOG_LEVEL option
|
|
|
|
|
|
in<a href="#Conf"> /etc/shorewall/shorewall.conf</a> and are disposed of
|
|
|
|
|
|
according to the TCP_FLAGS_DISPOSITION option.<br>
|
|
|
|
|
|
<b><br>
|
|
|
|
|
|
blacklist</b> - This option causes incoming packets
|
2003-03-22 01:25:40 +01:00
|
|
|
|
on this interface to be checked against the <a
|
2003-01-14 18:18:42 +01:00
|
|
|
|
href="#Blacklist">blacklist</a>.<b><br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
dhcp</b> - The interface is assigned
|
|
|
|
|
|
an IP address via DHCP or is used by a DHCP server running
|
|
|
|
|
|
on the firewall. The firewall will be configured to allow
|
|
|
|
|
|
DHCP traffic to and from the interface even when the firewall
|
|
|
|
|
|
is stopped. You may also wish to use this option if you have a static
|
|
|
|
|
|
IP but you are on a LAN segment that has a lot of Laptops that
|
|
|
|
|
|
use DHCP and you select the <b>norfc1918 </b>option (see below).</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p> <b>norfc1918</b> - Packets arriving on this interface and that
|
|
|
|
|
|
have a source address that is reserved in RFC 1918 or in other
|
2003-03-22 01:25:40 +01:00
|
|
|
|
RFCs will be dropped after being optionally logged. If <a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
href="#Conf">packet mangling is enabled in /etc/shorewall/shorewall.conf</a>
|
|
|
|
|
|
, then packets arriving on this interface that have a
|
|
|
|
|
|
destination address that is reserved by one of these RFCs will
|
2003-03-07 00:41:31 +01:00
|
|
|
|
also be logged and dropped.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
Addresses blocked by the standard <a
|
|
|
|
|
|
href="#rfc1918"> <b>rfc1918 </b>file</a> include those
|
|
|
|
|
|
addresses reserved by RFC1918 plus other ranges reserved by
|
2003-03-07 00:41:31 +01:00
|
|
|
|
the IANA or by other RFCs.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p> Beware that as IPv4 addresses become in increasingly short supply,
|
|
|
|
|
|
ISPs are beginning to use RFC 1918 addresses within their
|
|
|
|
|
|
own infrastructure. Also, many cable and DSL "modems" have
|
|
|
|
|
|
an RFC 1918 address that can be used through a web browser for
|
|
|
|
|
|
management and monitoring functions. If you want to specify
|
|
|
|
|
|
<b>norfc1918</b> on your external interface but need to allow
|
2003-03-22 01:25:40 +01:00
|
|
|
|
access to certain addresses from the above list, see <a
|
|
|
|
|
|
href="FAQ.htm#faq14">FAQ 14.</a></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p> <b> routefilter</b> - Invoke the Kernel's route filtering
|
|
|
|
|
|
(anti-spoofing) facility on this interface. The kernel
|
|
|
|
|
|
will reject any packets incoming on this interface that have
|
|
|
|
|
|
a source address that would be routed outbound through another
|
|
|
|
|
|
interface on the firewall. <font color="#ff0000">Warning:
|
|
|
|
|
|
</font>If you specify this option for an interface then the
|
|
|
|
|
|
interface must be up prior to starting the firewall.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p> <b>dropunclean</b> - Packets from this interface that
|
|
|
|
|
|
are selected by the 'unclean' match target in iptables will
|
|
|
|
|
|
be <a href="#LogUnclean">optionally logged</a> and then dropped.
|
|
|
|
|
|
<font color="#ff0000"><b>Warning: This feature requires
|
|
|
|
|
|
that UNCLEAN match support be configured in your kernel,
|
|
|
|
|
|
either in the kernel itself or as a module. UNCLEAN
|
|
|
|
|
|
support is broken in some versions of the kernel but appears
|
|
|
|
|
|
to work ok in 2.4.17-rc1.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
Update 12/17/2001:
|
|
|
|
|
|
</b></font>The unclean match patch from
|
|
|
|
|
|
2.4.17-rc1 is <a
|
|
|
|
|
|
href="ftp://ftp.shorewall.net/pub/shorewall/misc/unclean.patch">available
|
|
|
|
|
|
for download</a>. I am currently running
|
2003-03-22 01:25:40 +01:00
|
|
|
|
this patch applied to kernel 2.4.16.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><font color="#ff0000"><b>Update 12/20/2001: </b></font>I've
|
|
|
|
|
|
seen a number of tcp connection requests
|
|
|
|
|
|
with OPT (020405B4<u>0000080A</u>...) being
|
|
|
|
|
|
dropped in the <i>badpkt</i> chain. This appears to be
|
|
|
|
|
|
a bug in the remote TCP stack whereby it is 8-byte aligning
|
|
|
|
|
|
a timestamp (TCP option 8) but rather than padding
|
|
|
|
|
|
with 0x01 it is padding with 0x00. It's a tough
|
|
|
|
|
|
call whether to deny people access to your servers
|
|
|
|
|
|
because of this rather minor bug in their networking
|
|
|
|
|
|
software. If you wish to disable the check that
|
|
|
|
|
|
causes these connections to be dropped, <a
|
|
|
|
|
|
href="ftp://ftp.shorewall.net/pub/shorewall/misc/unclean1.patch">here's
|
|
|
|
|
|
a kernel patch</a> against 2.4.17-rc2.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b>logunclean </b>- This option works like <b>dropunclean</b>
|
|
|
|
|
|
with the exception that packets selected
|
|
|
|
|
|
by the 'unclean' match target in iptables
|
|
|
|
|
|
are logged <i>but not dropped</i>. The
|
|
|
|
|
|
level at which the packets are logged is determined by
|
|
|
|
|
|
the setting of <a href="#LogUnclean">LOGUNCLEAN</a> and if
|
|
|
|
|
|
LOGUNCLEAN has not been set, "info" is assumed.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b>proxyarp </b>(Added in version 1.3.5) - This option causes
|
|
|
|
|
|
Shorewall to set /proc/sys/net/ipv4/conf/<i><interface></i>/proxy_arp
|
|
|
|
|
|
and is used when implementing Proxy ARP
|
|
|
|
|
|
Sub-netting as described at
|
|
|
|
|
|
<a href="http://www.tldp.org/HOWTO/mini/Proxy-ARP-Subnet/">
|
|
|
|
|
|
http://www.tldp.org/HOWTO/mini/Proxy-ARP-Subnet/</a>. Do <u>
|
|
|
|
|
|
not</u> set this option if you are implementing Proxy
|
|
|
|
|
|
ARP through entries in <a href="#ProxyArp">
|
|
|
|
|
|
/etc/shorewall/proxyarp</a>.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
<b>maclist</b> (Added in version 1.3.10)
|
|
|
|
|
|
- If this option is specified, all connection requests from this
|
|
|
|
|
|
interface are subject to <a href="MAC_Validation.html">MAC Verification</a>.
|
2003-03-22 01:25:40 +01:00
|
|
|
|
May only be specified for ethernet interfaces.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<p>My recommendations concerning options:<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>External Interface -- <b>tcpflags,blacklist,norfc1918,routefilter</b></li>
|
|
|
|
|
|
<li>Wireless Interface -- <b>maclist,routefilter,tcpflags</b><br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li>Don't use <b>dropunclean</b> -- It's broken
|
2003-03-22 01:25:40 +01:00
|
|
|
|
in my opinion</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>Use <b>logunclean</b> only when you are trying
|
2003-03-22 01:25:40 +01:00
|
|
|
|
to debug a problem</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>Use <b>dhcp </b>and <b>proxyarp</b> when
|
|
|
|
|
|
needed.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<p> </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Example 1: You have a conventional firewall setup in which eth0 connects
|
|
|
|
|
|
to a Cable or DSL modem and eth1 connects to your local
|
|
|
|
|
|
network and eth0 gets its IP address via DHCP. You want to
|
|
|
|
|
|
check all packets entering from the internet against the <a
|
|
|
|
|
|
href="#Blacklist">black list</a>. Your /etc/shorewall/interfaces file
|
|
|
|
|
|
would be as follows:</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> BROADCAST</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>eth0</td>
|
|
|
|
|
|
<td>detect</td>
|
|
|
|
|
|
<td>dhcp,norfc1918,blacklist</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>eth1</td>
|
|
|
|
|
|
<td>detect</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>Example 2: You have a standalone dialup GNU/Linux System. Your /etc/shorewall/interfaces
|
2003-03-22 01:25:40 +01:00
|
|
|
|
file would be:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> BROADCAST</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>ppp0</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>Example 3: You have local interface eth1 with two IP addresses -
|
|
|
|
|
|
192.168.1.1/24 and 192.168.12.1/24</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> BROADCAST</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>eth1</td>
|
|
|
|
|
|
<td>192.168.1.255,192.168.12.255</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><font color="#660066"><a name="Hosts"></a> </font>/etc/shorewall/hosts
|
2003-03-22 01:25:40 +01:00
|
|
|
|
Configuration</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>For most applications, specifying zones entirely in terms of network
|
|
|
|
|
|
interfaces is sufficient. There may be times though where you need to define
|
|
|
|
|
|
a zone to be a more general collection of hosts. This is the purpose of
|
|
|
|
|
|
the /etc/shorewall/hosts file.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b><font color="#ff0000">WARNING: </font>The only times that you need entries
|
|
|
|
|
|
in /etc/shorewall/hosts are:<br>
|
|
|
|
|
|
</b></p>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<ol>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>You have more than one zone connecting through a single interface;
|
2003-03-22 01:25:40 +01:00
|
|
|
|
or</b></li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>You have a zone that has multiple subnetworks that connect through
|
|
|
|
|
|
a single interface and you want the Shorewall box to route traffic between
|
2003-03-22 01:25:40 +01:00
|
|
|
|
those subnetworks.</b><br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</ol>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<b>IF YOU DON'T HAVE EITHER OF THOSE SITUATIONS THEN DON'T TOUCH THIS FILE!!</b>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>Columns in this file are:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> ZONE </b> - A zone defined
|
2003-03-22 01:25:40 +01:00
|
|
|
|
in the <a href="#Zones">/etc/shorewall/zones</a> file.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> HOST(S)</b> - The name of
|
|
|
|
|
|
a network interface followed by a colon (":") followed
|
2003-03-22 01:25:40 +01:00
|
|
|
|
by either:</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ol>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>An IP address (example
|
2003-03-22 01:25:40 +01:00
|
|
|
|
- eth1:192.168.1.3)</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>A subnet in CIDR
|
|
|
|
|
|
notation<i> </i>(example - eth2:192.168.2.0/24)</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ol>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>The interface name much match an entry in /etc/shorewall/interfaces.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> OPTIONS</b> - A comma-separated
|
2003-03-22 01:25:40 +01:00
|
|
|
|
list of option</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
<p><b>maclist - </b>Added in version 1.3.10. If specified, connection
|
|
|
|
|
|
requests from the hosts specified in this entry are subject
|
|
|
|
|
|
to <a href="MAC_Validation.html">MAC Verification</a>. This option is
|
|
|
|
|
|
only valid for ethernet interfaces.<br>
|
|
|
|
|
|
</p>
|
|
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>If you don't define any hosts for a zone, the hosts in the zone default
|
|
|
|
|
|
to i0:0.0.0.0/0 , i1:0.0.0.0/0, ... where i0, i1, ... are
|
|
|
|
|
|
the interfaces to the zone.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b><font size="4" color="#ff0000">Note: </font></b> You probably DON'T
|
|
|
|
|
|
want to specify any hosts for your internet zone since the hosts that
|
|
|
|
|
|
you specify will be the only ones that you will be able to access without
|
2003-03-22 01:25:40 +01:00
|
|
|
|
adding additional rules.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p>Example 1:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Your local interface is eth1 and you have two groups of local hosts that
|
2003-03-22 01:25:40 +01:00
|
|
|
|
you want to make into separate zones:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>192.168.1.0/25 </li>
|
|
|
|
|
|
<li>192.168.1.128/</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p>Your /etc/shorewall/interfaces file might look like:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> BROADCAST</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>eth0</td>
|
|
|
|
|
|
<td>detect</td>
|
|
|
|
|
|
<td>dhcp,norfc1918</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>eth1</td>
|
|
|
|
|
|
<td>192.168.1.127,192.168.1.255<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> The '-' in the ZONE column for eth1 tells Shorewall that eth1 interfaces
|
2003-03-22 01:25:40 +01:00
|
|
|
|
to multiple zones.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Your /etc/shorewall/hosts file might look like:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<blockquote> <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica">
|
|
|
|
|
|
</font>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> HOST(S)</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc1</td>
|
|
|
|
|
|
<td>eth1:192.168.1.0/25</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc2</td>
|
|
|
|
|
|
<td>eth1:192.168.1.128/25</td>
|
|
|
|
|
|
<td><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p>Example 2:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Your local interface is eth1 and you have two groups of local hosts that
|
|
|
|
|
|
you want to consider as one zone and you want Shorewall to route between them:</p>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>192.168.1.0/25 </li>
|
|
|
|
|
|
<li>192.168.1.128/25</li>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p> Your /etc/shorewall/interfaces file might look like:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> BROADCAST</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>eth0</td>
|
|
|
|
|
|
<td>detect</td>
|
|
|
|
|
|
<td>dhcp,norfc1918</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td>eth1</td>
|
|
|
|
|
|
<td>192.168.1.127,192.168.1.255<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-02-20 00:21:55 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p> Your /etc/shorewall/hosts file might look like:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<blockquote> <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica">
|
|
|
|
|
|
</font>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> HOST(S)</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>eth1:192.168.1.0/25</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>eth1:192.168.1.128/25</td>
|
|
|
|
|
|
<td><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<h4><font color="#660066"><a name="Nested"></a> Nested and Overlapping Zones</font></h4>
|
|
|
|
|
|
|
|
|
|
|
|
<p> The /etc/shorewall/interfaces and /etc/shorewall/hosts file allow
|
|
|
|
|
|
you to define nested or overlapping zones. Such overlapping/nested zones
|
|
|
|
|
|
are allowed and Shorewall processes zones in the order that
|
|
|
|
|
|
they appear in the /etc/shorewall/zones file. So if you have
|
|
|
|
|
|
nested zones, you want the sub-zone to appear before the super-zone
|
|
|
|
|
|
and in the case of overlapping zones, the rules that will apply
|
|
|
|
|
|
to hosts that belong to both zones is determined by which zone
|
|
|
|
|
|
appears first in /etc/shorewall/zones.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p> Hosts that belong to more than one zone may be managed by the rules
|
|
|
|
|
|
of all of those zones. This is done through use of the special
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<a href="#CONTINUE">CONTINUE policy</a> described below.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<h2><font color="#660066"><a name="Policy"></a> </font>/etc/shorewall/policy
|
|
|
|
|
|
Configuration.</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>This file is used to describe the firewall policy regarding establishment
|
|
|
|
|
|
of connections. Connection establishment is described in
|
|
|
|
|
|
terms of <i>clients</i> who initiate connections and <i> servers
|
|
|
|
|
|
</i>who receive those connection requests. Policies defined
|
|
|
|
|
|
in /etc/shorewall/policy describe which zones are allowed
|
2003-03-07 00:41:31 +01:00
|
|
|
|
to establish connections with other zones.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Policies established in /etc/shorewall/policy can be viewed as default
|
|
|
|
|
|
policies. If no rule in /etc/shorewall/rules applies to
|
|
|
|
|
|
a particular connection request then the policy from /etc/shorewall/policy
|
2003-03-22 01:25:40 +01:00
|
|
|
|
is applied.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>Four policies are defined:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> ACCEPT</b> - The connection
|
2003-03-22 01:25:40 +01:00
|
|
|
|
is allowed.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> DROP</b> - The connection
|
|
|
|
|
|
request is ignored.</li>
|
|
|
|
|
|
<li><b> REJECT</b> - The connection
|
|
|
|
|
|
request is rejected with an RST (TCP) or an ICMP destination-unreachable
|
2003-03-22 01:25:40 +01:00
|
|
|
|
packet being returned to the client.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> CONTINUE </b> - The connection
|
|
|
|
|
|
is neither ACCEPTed, DROPped nor REJECTed. CONTINUE may
|
|
|
|
|
|
be used when one or both of the zones named in the entry are
|
|
|
|
|
|
sub-zones of or intersect with another zone. For more information,
|
2003-03-22 01:25:40 +01:00
|
|
|
|
see below.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>NONE</b> - (Added in version 1.4.1) - Shorewall should not set
|
|
|
|
|
|
up any infrastructure for handling traffic from the SOURCE zone to the DEST
|
|
|
|
|
|
zone. When this policy is specified, the <b>LOG LEVEL </b>and <b>BURST:LIMIT
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</b>columns must be left blank.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p> For each policy specified in /etc/shorewall/policy, you can indicate
|
|
|
|
|
|
that you want a message sent to your system log each time
|
2003-03-22 01:25:40 +01:00
|
|
|
|
that the policy is applied.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Entries in /etc/shorewall/policy have four columns as follows:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ol>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li> <b> SOURCE</b>
|
|
|
|
|
|
- The name of a client zone (a zone defined in the <a
|
|
|
|
|
|
href="#Zones"> /etc/shorewall/zones file</a> , the
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<a href="#Conf">name of the firewall zone</a> or "all").</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li> <b> DEST</b>
|
|
|
|
|
|
- The name of a destination zone (a zone defined in the <a
|
|
|
|
|
|
href="#Zones"> /etc/shorewall/zones file</a> , the <a
|
|
|
|
|
|
href="#Conf">name of the firewall zone</a> or "all"). Shorewall automatically
|
|
|
|
|
|
allows all traffic from the firewall to itself so the <a
|
|
|
|
|
|
href="#Conf">name of the firewall zone</a> cannot appear in both the
|
|
|
|
|
|
SOURCE and DEST columns.</li>
|
|
|
|
|
|
<li> <b> POLICY</b>
|
|
|
|
|
|
- The default policy for connection requests from the SOURCE
|
|
|
|
|
|
zone to the DESTINATION zone.</li>
|
|
|
|
|
|
<li> <b> LOG
|
|
|
|
|
|
LEVEL</b> - Optional. If left empty, no log message is generated
|
|
|
|
|
|
when the policy is applied. Otherwise, this column should
|
|
|
|
|
|
contain an integer or name indicating a <a
|
2003-02-04 16:26:02 +01:00
|
|
|
|
href="shorewall_logging.html">syslog level</a>.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li> <b>LIMIT:BURST
|
|
|
|
|
|
</b>- Optional. If left empty, TCP connection requests
|
|
|
|
|
|
from the <b>SOURCE</b> zone to the <b>DEST</b> zone will
|
|
|
|
|
|
not be rate-limited. Otherwise, this column specifies the maximum
|
|
|
|
|
|
rate at which TCP connection requests will be accepted followed
|
|
|
|
|
|
by a colon (":") followed by the maximum burst size that will
|
|
|
|
|
|
be tolerated. Example: <b> 10/sec:40</b> specifies that the
|
|
|
|
|
|
maximum rate of TCP connection requests allowed will be 10 per
|
|
|
|
|
|
second and a burst of 40 connections will be tolerated. Connection
|
|
|
|
|
|
requests in excess of these limits will be dropped.</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ol>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p> In the SOURCE and DEST columns, you can enter "all" to indicate all
|
2003-03-22 01:25:40 +01:00
|
|
|
|
zones. </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> The policy file installed by default is as follows:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<blockquote> <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica">
|
|
|
|
|
|
</font>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b> POLICY</b></td>
|
|
|
|
|
|
<td><b> LOG LEVEL</b></td>
|
|
|
|
|
|
<td><b>LIMIT:BURST</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>ACCEPT</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<td> <br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>DROP</td>
|
|
|
|
|
|
<td>info</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>REJECT</td>
|
|
|
|
|
|
<td>info</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-02-04 16:26:02 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> This table may be interpreted as follows:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>All connection requests from the
|
2003-03-22 01:25:40 +01:00
|
|
|
|
local network to hosts on the internet are accepted.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>All connection requests originating
|
2003-03-22 01:25:40 +01:00
|
|
|
|
from the internet are ignored and logged at level KERNEL.INFO.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>All other connection requests are
|
2003-03-22 01:25:40 +01:00
|
|
|
|
rejected and logged.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p><b><font size="4" color="#ff0000">WARNING:</font></b></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><font color="#ff0000"><b> The firewall script processes</b> <b> the
|
|
|
|
|
|
/etc/shorewall/policy file from top to bottom and <u>uses
|
|
|
|
|
|
the first applicable policy that it finds.</u> For example,
|
|
|
|
|
|
in the following policy file, the policy for (loc, loc) connections
|
|
|
|
|
|
would be ACCEPT as specified in the first entry even though the
|
2003-03-22 01:25:40 +01:00
|
|
|
|
third entry in the file specifies REJECT.</b></font></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-01-22 01:37:23 +01:00
|
|
|
|
<blockquote> <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b>POLICY</b></td>
|
|
|
|
|
|
<td><b>LOG LEVEL</b></td>
|
|
|
|
|
|
<td><b>LIMIT:BURST</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>ACCEPT</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>DROP</td>
|
|
|
|
|
|
<td>info</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>REJECT</td>
|
|
|
|
|
|
<td>info</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<h4><a name="IntraZone"></a>IntraZone Traffic</h4>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Shorewall allows a zone to be associated with more than one interface or
|
|
|
|
|
|
with multiple networks that interface through a single interface. Beginning
|
|
|
|
|
|
with Shorewall 1.4.1, Shorewall will ACCEPT all traffic from a zone to itself
|
|
|
|
|
|
provided that there is no explicit policy governing traffic from that zone
|
|
|
|
|
|
to itself (an explicit policy does not specify "all" in either the SOURCE
|
|
|
|
|
|
or DEST column) and that there are no rules concerning connections from that
|
|
|
|
|
|
zone to itself. If there is an explicit policy or if there are one or more
|
|
|
|
|
|
rules, then traffic within the zone is handled just like traffic between zones
|
|
|
|
|
|
is.<br>
|
|
|
|
|
|
|
|
|
|
|
|
<p>Any time that you have multiple interfaces associated with a single zone,
|
|
|
|
|
|
you should ask yourself if you really want traffic routed between those interfaces.
|
2003-03-22 01:25:40 +01:00
|
|
|
|
Cases where you might not want that behavior are:<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<ol>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>Multiple 'net' interfaces to different ISPs. You don't want to route
|
2003-03-22 01:25:40 +01:00
|
|
|
|
traffic from one ISP to the other through your firewall.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>Multiple VPN clients. You don't necessarily want them to all be able
|
2003-03-22 01:25:40 +01:00
|
|
|
|
to communicate between themselves using your gateway/router.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</ol>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<h4><font color="#660066"><a name="CONTINUE"></a> The CONTINUE
|
|
|
|
|
|
policy</font></h4>
|
|
|
|
|
|
|
|
|
|
|
|
<p> Where zones are <a href="#Nested">nested or overlapping</a> , the
|
|
|
|
|
|
CONTINUE policy allows hosts that are within multiple zones
|
|
|
|
|
|
to be managed under the rules of all of these zones. Let's look
|
2003-03-22 01:25:40 +01:00
|
|
|
|
at an example:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> /etc/shorewall/zones:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> DISPLAY</b></td>
|
|
|
|
|
|
<td><b> COMMENTS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>sam</td>
|
|
|
|
|
|
<td>Sam</td>
|
|
|
|
|
|
<td>Sam's system at home</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>Internet</td>
|
|
|
|
|
|
<td>The Internet</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>Loc</td>
|
|
|
|
|
|
<td>Local Network</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> /etc/shorewall/interfaces:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> BROADCAST</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>eth0</td>
|
|
|
|
|
|
<td>detect</td>
|
|
|
|
|
|
<td>dhcp,norfc1918</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>eth1</td>
|
|
|
|
|
|
<td>detect</td>
|
|
|
|
|
|
<td><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> /etc/shorewall/hosts:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<blockquote> <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2002-11-09 19:06:34 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ZONE</b></td>
|
|
|
|
|
|
<td><b> HOST(S)</b></td>
|
|
|
|
|
|
<td><b> OPTIONS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>eth0:0.0.0.0/0</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>sam</td>
|
|
|
|
|
|
<td>eth0:206.191.149.197</td>
|
|
|
|
|
|
<td><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-11-09 19:06:34 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> Note that Sam's home system is a member of both the <b>sam</b> zone
|
|
|
|
|
|
and the <b>net</b>
|
|
|
|
|
|
zone and <a href="#Nested"> as described above</a> , that means
|
2003-03-22 01:25:40 +01:00
|
|
|
|
that <b>sam</b> must be listed before <b>net</b> in /etc/shorewall/zones.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> /etc/shorewall/policy:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<blockquote> <font
|
2003-01-22 01:37:23 +01:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font><font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2003-01-22 01:37:23 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> SOURCE</b></td>
|
|
|
|
|
|
<td><b> DEST</b></td>
|
|
|
|
|
|
<td><b> POLICY</b></td>
|
|
|
|
|
|
<td><b> LOG LEVEL</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>ACCEPT</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>sam</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>CONTINUE</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>DROP</td>
|
|
|
|
|
|
<td>info</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>REJECT</td>
|
|
|
|
|
|
<td>info</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-02-25 20:24:41 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> The second entry above says that when Sam is the client, connection
|
|
|
|
|
|
requests should first be process under rules where the source
|
|
|
|
|
|
zone is <b>sam</b> and if there is no match then the connection
|
|
|
|
|
|
request should be treated under rules where the source zone
|
|
|
|
|
|
is <b>net</b>. It is important that this policy be listed BEFORE
|
|
|
|
|
|
the next policy (<b>net</b> to <b>all</b>).</p>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> Partial /etc/shorewall/rules:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<blockquote> <font
|
|
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font><font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>ACTION</b></td>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b> PROTO</b></td>
|
|
|
|
|
|
<td><b>DEST<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>ORIGINAL<br>
|
|
|
|
|
|
DEST</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>...</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>DNAT</td>
|
|
|
|
|
|
<td>sam</td>
|
|
|
|
|
|
<td>loc:192.168.1.3</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ssh</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>DNAT</td>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>loc:192.168.1.5</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>www</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>...</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-03-07 00:41:31 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> Given these two rules, Sam can connect to the firewall's internet interface
|
|
|
|
|
|
with ssh and the connection request will be forwarded to
|
|
|
|
|
|
192.168.1.3. Like all hosts in the <b>net</b> zone, Sam can
|
|
|
|
|
|
connect to the firewall's internet interface on TCP port 80
|
|
|
|
|
|
and the connection request will be forwarded to 192.168.1.5. The
|
|
|
|
|
|
order of the rules is not significant.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p> <a name="Exclude"></a>Sometimes it is necessary to suppress port forwarding
|
|
|
|
|
|
for a sub-zone. For example, suppose that all hosts can
|
|
|
|
|
|
SSH to the firewall and be forwarded to 192.168.1.5 EXCEPT
|
|
|
|
|
|
Sam. When Sam connects to the firewall's external IP, he should
|
|
|
|
|
|
be connected to the firewall itself. Because of the way that Netfilter
|
2003-03-22 01:25:40 +01:00
|
|
|
|
is constructed, this requires two rules as follows:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<p> </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<font face="Century Gothic, Arial, Helvetica"> </font><font
|
|
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>ACTION</b></td>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b> PROTO</b></td>
|
|
|
|
|
|
<td><b>DEST<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>ORIGINAL<br>
|
|
|
|
|
|
DEST</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>...</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>DNAT</td>
|
|
|
|
|
|
<td>sam</td>
|
|
|
|
|
|
<td>fw</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ssh</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>DNAT</td>
|
|
|
|
|
|
<td>net!sam</td>
|
|
|
|
|
|
<td>loc:192.168.1.3</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ssh</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>...</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-11-09 19:06:34 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>The first rule allows Sam SSH access to the firewall. The second
|
|
|
|
|
|
rule says that any clients from the net zone
|
|
|
|
|
|
with the exception of those in the 'sam' zone
|
|
|
|
|
|
should have their connection port forwarded
|
|
|
|
|
|
to 192.168.1.3. If you need to exclude
|
|
|
|
|
|
more than one zone in this way,
|
|
|
|
|
|
you can list
|
|
|
|
|
|
the zones separated by commas (e.g., net!sam,joe,fred).
|
|
|
|
|
|
This technique also may be used when
|
|
|
|
|
|
the ACTION is REDIRECT.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><font color="#660066"><a name="Rules"></a> </font>/etc/shorewall/rules</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>The /etc/shorewall/rules file defines exceptions to the policies established
|
|
|
|
|
|
in the /etc/shorewall/policy file. There is one entry in
|
2003-03-07 00:41:31 +01:00
|
|
|
|
/etc/shorewall/rules for each of these rules. <br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p>Shorewall automatically enables firewall->firewall traffic over the
|
|
|
|
|
|
loopback interface (lo) -- that traffic cannot be regulated using
|
|
|
|
|
|
rules and any rule that tries to regulate such traffic will generate
|
2003-03-22 01:25:40 +01:00
|
|
|
|
a warning and will be ignored.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<p>Entries in the file have the following columns:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>ACTION</b>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>ACCEPT, DROP, REJECT, CONTINUE.
|
|
|
|
|
|
These have the same meaning here as in the policy file
|
2003-03-22 01:25:40 +01:00
|
|
|
|
above.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>DNAT -- Causes the connection
|
|
|
|
|
|
request to be forwarded to the system specified in the
|
|
|
|
|
|
DEST column (port forwarding). "DNAT" stands for "<u>D</u>estination
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<u>N</u>etwork <u>A</u>ddress <u>T</u>ranslation"</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>DNAT- -- The above ACTION (DNAT) generates
|
|
|
|
|
|
two iptables rules: 1) and header-rewriting rule in the Netfilter
|
|
|
|
|
|
'nat' table and; 2) an ACCEPT rule in the Netfilter 'filter' table.
|
2003-03-22 01:25:40 +01:00
|
|
|
|
DNAT- works like DNAT but only generates the header-rewriting rule.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li>REDIRECT -- Causes the connection
|
|
|
|
|
|
request to be redirected to a port on the local (firewall)
|
2003-03-22 01:25:40 +01:00
|
|
|
|
system.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>LOG - Log the packet -- requires a syslog level (see below).</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<p>The ACTION may optionally be followed by ":" and a <a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
href="shorewall_logging.html">syslog level</a> (example: REJECT:info). This
|
|
|
|
|
|
causes the packet to be logged at the specified level prior to being
|
|
|
|
|
|
processed according to the specified ACTION. Note: if the ACTION
|
|
|
|
|
|
is LOG then you MUST specify a syslog level.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
The use of DNAT or REDIRECT requires
|
2003-03-22 01:25:40 +01:00
|
|
|
|
that you have <a href="#NatEnabled">NAT enabled</a>.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>SOURCE</b> - Describes the source
|
|
|
|
|
|
hosts to which the rule applies.. The contents of this field
|
|
|
|
|
|
must begin with the name of a zone defined in /etc/shorewall/zones,
|
|
|
|
|
|
$FW or "all". If the ACTION is DNAT or REDIRECT, sub-zones
|
|
|
|
|
|
may be excluded from the rule by following the initial zone name
|
|
|
|
|
|
with "!' and a comma-separated list of those sub-zones to be
|
|
|
|
|
|
excluded. There is an <a href="#Exclude">example</a> above.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
If the source is not 'all' then the
|
|
|
|
|
|
source may be further restricted by adding a colon (":") followed
|
|
|
|
|
|
by a comma-separated list of qualifiers. Qualifiers are may
|
|
|
|
|
|
include:
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>An interface name - refers to
|
|
|
|
|
|
any connection requests arriving on the specified
|
|
|
|
|
|
interface (example loc:eth4). Beginning with Shorwall 1.3.9, the
|
|
|
|
|
|
interface name may optionally be followed by a colon (":") and an IP
|
|
|
|
|
|
address or subnet (examples: loc:eth4:192.168.4.22, net:eth0:192.0.2.0/24).</li>
|
|
|
|
|
|
<li>An IP address - refers to a connection
|
|
|
|
|
|
request from the host with the specified address
|
|
|
|
|
|
(example net:155.186.235.151). If the ACTION is DNAT, this must
|
2003-03-07 00:41:31 +01:00
|
|
|
|
not be a DNS name.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>A MAC Address in <a
|
2003-03-22 01:25:40 +01:00
|
|
|
|
href="#MAC">Shorewall format</a>.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>A subnet - refers to a connection
|
|
|
|
|
|
request from any host in the specified subnet (example
|
2003-03-22 01:25:40 +01:00
|
|
|
|
net:155.186.235.0/24).</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>DEST</b> - Describes the destination
|
|
|
|
|
|
host(s) to which the rule applies. May take most of the forms
|
|
|
|
|
|
described above for SOURCE plus the following two additional
|
|
|
|
|
|
forms:
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>An IP address followed by a colon
|
|
|
|
|
|
and the port <u>number</u> that the server
|
|
|
|
|
|
is listening on (service names from /etc/services are not
|
|
|
|
|
|
allowed - example loc:192.168.1.3:80). <br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li>A single port number (again, service
|
|
|
|
|
|
names are not allowed) -- this form is only allowed if the
|
|
|
|
|
|
ACTION is REDIRECT and refers to a server running on the firewall
|
|
|
|
|
|
itself and listening on the specified port.</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Restrictions:<br>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>MAC addresses may not be specified.</li>
|
|
|
|
|
|
<li>In DNAT rules, only an IP address may be given -- DNS names
|
|
|
|
|
|
are not permitted.</li>
|
|
|
|
|
|
<li>You may not specify both an IP address and an interface name
|
2003-03-22 01:25:40 +01:00
|
|
|
|
in the DEST column.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b> PROTO</b> - Protocol. Must
|
|
|
|
|
|
be a protocol name from /etc/protocols, a number or "all".
|
|
|
|
|
|
Specifies the protocol of the connection request.</li>
|
|
|
|
|
|
<li><b> DEST PORT(S)</b> - Port
|
|
|
|
|
|
or port range (<low port>:<high port>) being connected
|
|
|
|
|
|
to. May only be specified if the protocol is tcp, udp
|
|
|
|
|
|
or icmp. For icmp, this column's contents are interpreted as
|
|
|
|
|
|
an icmp type. If you don't want to specify DEST PORT(S) but need
|
|
|
|
|
|
to include information in one of the columns to the right,
|
|
|
|
|
|
enter "-" in this column. You may give a list of ports and/or port ranges
|
|
|
|
|
|
separated by commas. Port numbers may be either integers or service
|
|
|
|
|
|
names from /etc/services.</li>
|
|
|
|
|
|
<li><b> SOURCE</b> <b>PORTS(S) </b>-
|
|
|
|
|
|
May be used to restrict the rule to a particular client
|
|
|
|
|
|
port or port range (a port range is specified as <low port
|
|
|
|
|
|
number>:<high port number>). If you don't want to
|
|
|
|
|
|
restrict client ports but want to specify something in the next column,
|
|
|
|
|
|
enter "-" in this column. If you wish to specify a list of port
|
|
|
|
|
|
number or ranges, separate the list elements with commas (with
|
|
|
|
|
|
no embedded white space). Port numbers may be either integers or
|
|
|
|
|
|
service names from /etc/services.</li>
|
|
|
|
|
|
<li><b>ORIGINAL DEST</b> - This column
|
2003-03-22 01:25:40 +01:00
|
|
|
|
may only be non-empty if the ACTION is DNAT or REDIRECT.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
If DNAT or REDIRECT is the ACTION and
|
|
|
|
|
|
the ORIGINAL DEST column is left empty, any connection request
|
|
|
|
|
|
arriving at the firewall from the SOURCE that matches the
|
|
|
|
|
|
rule will be forwarded or redirected. This works fine for connection
|
|
|
|
|
|
requests arriving from the internet where the firewall has
|
|
|
|
|
|
only a single external IP address. When the firewall has multiple
|
|
|
|
|
|
external IP addresses or when the SOURCE is other than the internet,
|
|
|
|
|
|
there will usually be a desire for the rule to only apply to
|
|
|
|
|
|
those connection requests directed to a particular IP address
|
|
|
|
|
|
(see Example 2 below for another usage). That IP address (or
|
|
|
|
|
|
a comma-separated list of such addresses) is specified in the
|
|
|
|
|
|
ORIGINAL DEST column.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
The IP address may be optionally followed
|
|
|
|
|
|
by ":" and a second IP address. This latter address, if present,
|
|
|
|
|
|
is used as the source address for packets forwarded to the
|
2003-03-22 01:25:40 +01:00
|
|
|
|
server (This is called "Source NAT" or SNAT).<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
<b><font color="#ff6633">Note: </font> When using SNAT,
|
|
|
|
|
|
it is a good idea to qualify the source with an IP address or subnet.
|
|
|
|
|
|
Otherwise, it is likely that SNAT will occur on connections other than
|
|
|
|
|
|
those described in the rule. The reason for this is that SNAT occurs in
|
|
|
|
|
|
the Netfilter POSTROUTING hook where it is not possible to restrict
|
2003-03-07 00:41:31 +01:00
|
|
|
|
the scope of a rule by incoming interface. <br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
</b>Example: DNAT loc<u>:192.168.1.0/24</u>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
loc:192.168.1.3 tcp www - 206.124.146.179:192.168.1.3<b><br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
</b>If SNAT is not used (no ":"
|
|
|
|
|
|
and second IP address), the original source address is
|
|
|
|
|
|
used. If you want any destination address to match the rule
|
|
|
|
|
|
but want to specify SNAT, simply use a colon followed by the SNAT
|
2003-03-22 01:25:40 +01:00
|
|
|
|
address.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p><b> <font face="Century Gothic, Arial, Helvetica"> <a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
name="PortForward"></a> </font>Example 1. </b> You wish to forward all
|
|
|
|
|
|
ssh connection requests from the internet to local system
|
2003-03-22 01:25:40 +01:00
|
|
|
|
192.168.1.3. </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<blockquote> <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<tr>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<td><b>ACTION</b></td>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b> PROTO</b></td>
|
|
|
|
|
|
<td><b>DEST<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>ORIGINAL<br>
|
|
|
|
|
|
DEST</b></td>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</tr>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tr>
|
|
|
|
|
|
<td>DNAT</td>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>loc:192.168.1.3</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ssh</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b> Example 2. </b> You want to redirect all local www connection requests
|
|
|
|
|
|
EXCEPT those
|
|
|
|
|
|
to your own http server (206.124.146.177)
|
|
|
|
|
|
to a Squid transparent proxy running
|
|
|
|
|
|
on the firewall and listening on port 3128. Squid will of course
|
|
|
|
|
|
require access to remote web servers. This example shows yet
|
|
|
|
|
|
another use for the ORIGINAL
|
|
|
|
|
|
DEST column; here, connection
|
|
|
|
|
|
requests that were NOT
|
|
|
|
|
|
<a href="#GettingStarted"> (notice the "!")</a> originally
|
|
|
|
|
|
destined to 206.124.146.177 are
|
|
|
|
|
|
redirected to local port 3128.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote> <font
|
|
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<tr>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<td><b>ACTION</b></td>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b> PROTO</b></td>
|
|
|
|
|
|
<td><b>DEST<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>ORIGINAL<br>
|
|
|
|
|
|
DEST</b></td>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</tr>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tr>
|
|
|
|
|
|
<td>REDIRECT</td>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>3128</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>www</td>
|
|
|
|
|
|
<td> -<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td>!206.124.146.177</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>ACCEPT</td>
|
|
|
|
|
|
<td>fw</td>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>www</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b>Example 3. </b> You want to run a web server at 155.186.235.222 in your
|
|
|
|
|
|
DMZ and have it accessible remotely and locally. the DMZ is managed
|
|
|
|
|
|
by Proxy ARP or by classical sub-netting.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote> <font
|
2002-09-16 19:13:10 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font><font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<tr>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<td><b>ACTION</b></td>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b> PROTO</b></td>
|
|
|
|
|
|
<td><b>DEST<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>ORIGINAL<br>
|
|
|
|
|
|
DEST</b></td>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</tr>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tr>
|
|
|
|
|
|
<td>ACCEPT</td>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>dmz:155.186.235.222</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>www</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>ACCEPT</td>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>dmz:155.186.235.222</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>www</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b> Example 4. </b> You want to run wu-ftpd on 192.168.2.2 in your masqueraded
|
|
|
|
|
|
DMZ. Your internet interface address is 155.186.235.151
|
|
|
|
|
|
and you want the FTP server to be accessible from the internet
|
|
|
|
|
|
in addition to the local 192.168.1.0/24 and dmz 192.168.2.0/24
|
|
|
|
|
|
subnetworks. Note that since the server is in the 192.168.2.0/24
|
|
|
|
|
|
subnetwork, we can assume that access to the server from that subnet
|
|
|
|
|
|
will not involve the firewall (<a href="FAQ.htm#faq2">but see FAQ
|
|
|
|
|
|
2</a>). Note that unless you have more than one external
|
|
|
|
|
|
IP address, you can leave
|
|
|
|
|
|
the ORIGINAL DEST column
|
|
|
|
|
|
blank in the first rule. You
|
|
|
|
|
|
cannot leave it blank in the
|
|
|
|
|
|
second rule though because
|
|
|
|
|
|
then <u>all ftp connections</u>
|
|
|
|
|
|
originating in the local subnet 192.168.1.0/24 would
|
|
|
|
|
|
be sent to 192.168.2.2 <u>
|
|
|
|
|
|
regardless of the site that
|
|
|
|
|
|
the user was trying to
|
|
|
|
|
|
connect to</u>. That is
|
|
|
|
|
|
clearly not what you want
|
|
|
|
|
|
<img border="0" src="images/SY00079.gif"
|
|
|
|
|
|
width="20" height="20" align="top">
|
|
|
|
|
|
.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote> <font
|
|
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font><font
|
|
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
|
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
|
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>ACTION</b></td>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b> PROTO</b></td>
|
|
|
|
|
|
<td><b>DEST<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>ORIGINAL<br>
|
|
|
|
|
|
DEST</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>DNAT</td>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>dmz:192.168.2.2</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ftp</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>DNAT</td>
|
|
|
|
|
|
<td>loc:192.168.1.0/24</td>
|
|
|
|
|
|
<td>dmz:192.168.2.2</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ftp</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>155.186.235.151</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
</table>
|
|
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>If you are running wu-ftpd, you should restrict the range of passive
|
|
|
|
|
|
in your /etc/ftpaccess file. I only need a few simultaneous FTP sessions
|
|
|
|
|
|
so I use port range 65500-65535. In /etc/ftpaccess, this
|
2003-03-22 01:25:40 +01:00
|
|
|
|
entry is appropriate:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<p> passive ports 0.0.0.0/0 65500 65534</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>If you are running pure-ftpd, you would include "-p 65500:65534" on
|
2003-03-22 01:25:40 +01:00
|
|
|
|
the pure-ftpd runline.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>The important point here is to ensure that the port range used for FTP
|
|
|
|
|
|
passive connections is unique and will not overlap with
|
2003-03-07 00:41:31 +01:00
|
|
|
|
any usage on the firewall system.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><b>Example 5. </b>You wish to allow unlimited
|
|
|
|
|
|
DMZ access to the host with MAC address
|
|
|
|
|
|
02:00:08:E3:FA:55.</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<blockquote> <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>ACTION</b></td>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b> PROTO</b></td>
|
|
|
|
|
|
<td><b>DEST<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>ORIGINAL<br>
|
|
|
|
|
|
DEST</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>ACCEPT</td>
|
|
|
|
|
|
<td>loc:~02-00-08-E3-FA-55</td>
|
|
|
|
|
|
<td>dmz</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<b>Example 6.</b> You wish to allow access to the SMTP server
|
|
|
|
|
|
in your DMZ from all zones.<br>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<table cellpadding="2" cellspacing="0" border="1">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td valign="top"><b>ACTION</b><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><b>SOURCE<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>DEST<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>PROTO<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>DEST<br>
|
|
|
|
|
|
PORT(S)<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>ORIGINAL<br>
|
|
|
|
|
|
DEST<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td valign="top">ACCEPT<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">all<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">dmz<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">tcp<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">25<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-11-24 21:08:19 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
Note: When 'all' is used as a source or destination,
|
|
|
|
|
|
intra-zone traffic is not affected. In this example, if there
|
|
|
|
|
|
were two DMZ interfaces then the above rule would NOT enable SMTP
|
|
|
|
|
|
traffic between hosts on these interfaces.<br>
|
|
|
|
|
|
</blockquote>
|
|
|
|
|
|
<b>Example 7 (For advanced users running Shorewall version
|
|
|
|
|
|
1.3.13 or later). </b>From the internet, you with to forward tcp
|
|
|
|
|
|
port 25 directed to 192.0.2.178 and 192.0.2.179 to host 192.0.2.177
|
|
|
|
|
|
in your DMZ. You also want to allow access from the internet directly
|
2003-03-07 00:41:31 +01:00
|
|
|
|
to tcp port 25 on 192.0.2.177. <br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<table cellpadding="2" cellspacing="0" border="1">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td valign="top"><b>ACTION</b><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><b>SOURCE<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>DEST<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>PROTO<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>DEST<br>
|
|
|
|
|
|
PORT(S)<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
<td valign="top"><b>ORIGINAL<br>
|
|
|
|
|
|
DEST<br>
|
|
|
|
|
|
</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td valign="top">DNAT-<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">net<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">dmz:192.0.2.177<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">tcp<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">25<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">0<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">192.0.2.178<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td valign="top">DNAT-<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">net<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">dmz:192.0.2.177<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">tcp<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">25<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">0<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">192.0.2.179<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td valign="top">ACCEPT<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">net<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">dmz:192.0.2.177<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">tcp<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">25<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-01-14 18:18:42 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
Using "DNAT-" rather than "DNAT" avoids two extra copies
|
2003-03-22 01:25:40 +01:00
|
|
|
|
of the third rule from being generated.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><a href="ports.htm">Look here for information on other services.</a>
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><a name="Common"> </a>/etc/shorewall/common</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>Shorewall allows definition of rules that apply between
|
|
|
|
|
|
all zones. By default, these rules
|
|
|
|
|
|
are defined in the file
|
|
|
|
|
|
/etc/shorewall/common.def
|
|
|
|
|
|
but may be modified to
|
|
|
|
|
|
suit individual
|
|
|
|
|
|
requirements. Rather than modify /etc/shorewall/common.def,
|
|
|
|
|
|
you should copy that
|
|
|
|
|
|
file to
|
|
|
|
|
|
/etc/shorewall/common
|
|
|
|
|
|
and modify that file.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p>The /etc/shorewall/common
|
|
|
|
|
|
file is expected to contain iptables
|
|
|
|
|
|
commands; rather than
|
|
|
|
|
|
running iptables
|
|
|
|
|
|
directly, you should run
|
|
|
|
|
|
it indirectly using the
|
|
|
|
|
|
Shorewall function 'run_iptables'.
|
|
|
|
|
|
That way, if iptables encounters an
|
|
|
|
|
|
error, the firewall will be safely
|
|
|
|
|
|
stopped.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><a name="Masq"></a> /etc/shorewall/masq</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>The /etc/shorewall/masq file is used to define classical IP Masquerading
|
|
|
|
|
|
and Source Network Address Translation (SNAT). There is one
|
|
|
|
|
|
entry in the file for each subnet that you want to masquerade.
|
2003-03-22 01:25:40 +01:00
|
|
|
|
In order to make use of this feature, you must have <a
|
2003-02-04 16:26:02 +01:00
|
|
|
|
href="#NatEnabled">NAT enabled</a> .</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Columns are:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> INTERFACE</b> - The interface
|
|
|
|
|
|
that will masquerade the subnet; this is normally your
|
|
|
|
|
|
internet interface. This interface name can be optionally qualified
|
|
|
|
|
|
by adding ":" and a subnet or host IP. When this qualification
|
|
|
|
|
|
is added, only packets addressed to that host or subnet will
|
|
|
|
|
|
be masqueraded. Beginning with Shorewall version 1.3.14, if you have
|
|
|
|
|
|
set ADD_SNAT_ALIASES=Yes in <a href="#Conf">/etc/shorewall/shorewall.conf</a>,
|
|
|
|
|
|
you can cause Shorewall to create an alias <i>label </i>of the form
|
|
|
|
|
|
<i>interfacename:digit </i>(e.g., eth0:0) by placing that label
|
|
|
|
|
|
in this column. See example 5 below. Alias labels created in this way
|
|
|
|
|
|
allow the alias to be visible to the ipconfig utility. <b>THAT IS THE
|
|
|
|
|
|
ONLY THING THAT THIS LABEL IS GOOD FOR AND IT MAY NOT APPEAR ANYWHERE ELSE
|
|
|
|
|
|
IN YOUR SHOREWALL CONFIGURATION.</b></li>
|
|
|
|
|
|
<li><b> SUBNET</b> - The subnet that
|
|
|
|
|
|
you want to have masqueraded through the INTERFACE. This
|
|
|
|
|
|
may be expressed as a single IP address, a subnet or an interface
|
|
|
|
|
|
name. In the latter instance, the interface must be configured and
|
|
|
|
|
|
started before Shorewall is started as Shorewall will determine
|
|
|
|
|
|
the subnet based on information obtained from the 'ip' utility.
|
|
|
|
|
|
<b><font color="#ff0000">When using Shorewall 1.3.13 or earlier, when
|
|
|
|
|
|
an interface name is specified, Shorewall will only masquerade traffic
|
|
|
|
|
|
from the first subnetwork on the named interface; if the interface interfaces
|
|
|
|
|
|
to more that one subnetwork, you will need to add additional entries to
|
|
|
|
|
|
this file for each of those other subnetworks. Beginning with Shorewall
|
|
|
|
|
|
1.3.14, shorewall will masquerade/SNAT traffic from any host that is routed
|
2003-03-07 00:41:31 +01:00
|
|
|
|
through the named interface.</font></b><br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
The subnet may be optionally followed
|
|
|
|
|
|
by "!' and a comma-separated list of addresses and/or subnets
|
2003-03-22 01:25:40 +01:00
|
|
|
|
that are to be excluded from masquerading.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>ADDRESS</b> - The source address
|
|
|
|
|
|
to be used for outgoing packets. This column is optional and
|
|
|
|
|
|
if left blank, the current primary IP address of the interface
|
|
|
|
|
|
in the first column is used. If you have a static IP on that interface,
|
|
|
|
|
|
listing it here makes processing of output packets a little
|
|
|
|
|
|
less expensive for the firewall. If you specify an address in this column,
|
|
|
|
|
|
it must be an IP address configured on the INTERFACE or you must have
|
|
|
|
|
|
ADD_SNAT_ALIASES enabled in <a href="#Conf">/etc/shorewall/shorewall.conf.</a></li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><b> Example 1: </b> You have eth0 connected to a cable modem and eth1
|
|
|
|
|
|
connected to your local subnetwork 192.168.9.0/24. Your
|
2003-03-22 01:25:40 +01:00
|
|
|
|
/etc/shorewall/masq file would look like: </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> SUBNET</b></td>
|
|
|
|
|
|
<td><b>ADDRESS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>eth0</td>
|
|
|
|
|
|
<td>192.168.9.0/24</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b> Example 2:</b> You have a number of IPSEC tunnels through ipsec0
|
|
|
|
|
|
and you want to masquerade traffic from your 192.168.9.0/24
|
2003-03-22 01:25:40 +01:00
|
|
|
|
subnet to the remote subnet 10.1.0.0/16 only.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> SUBNET</b></td>
|
|
|
|
|
|
<td><b>ADDRESS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>ipsec0:10.1.0.0/16</td>
|
|
|
|
|
|
<td>192.168.9.0/24</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b> Example 3:</b> You have a DSL line connected on eth0 and a local
|
|
|
|
|
|
network (192.168.10.0/24) connected
|
|
|
|
|
|
to eth1. You want all local->net
|
|
|
|
|
|
connections to use
|
|
|
|
|
|
source address
|
|
|
|
|
|
206.124.146.176.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> SUBNET</b></td>
|
|
|
|
|
|
<td><b>ADDRESS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>eth0</td>
|
|
|
|
|
|
<td>192.168.10.0/24</td>
|
|
|
|
|
|
<td>206.124.146.176</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b>Example 4: </b> Same as example 3 except that
|
|
|
|
|
|
you wish to exclude 192.168.10.44
|
|
|
|
|
|
and 192.168.10.45 from
|
|
|
|
|
|
the SNAT rule.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> SUBNET</b></td>
|
|
|
|
|
|
<td><b>ADDRESS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>eth0</td>
|
|
|
|
|
|
<td>192.168.10.0/24!192.168.10.44,192.168.10.45</td>
|
|
|
|
|
|
<td>206.124.146.176</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-03-07 00:41:31 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
<b>Example 5 (Shorewall version >= 1.3.14): </b>You have a second
|
|
|
|
|
|
IP address (206.124.146.177) assigned to you and wish to use it for SNAT
|
|
|
|
|
|
of the subnet 192.168.12.0/24. You want to give that address the name
|
|
|
|
|
|
eth0:0. You must have ADD_SNAT_ALIASES=Yes in <a href="#Conf">/etc/shorewall/shorewall.conf</a>.<br>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-01-31 22:50:51 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> SUBNET</b></td>
|
|
|
|
|
|
<td><b>ADDRESS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>eth0:0</td>
|
|
|
|
|
|
<td>192.168.12.0/24</td>
|
|
|
|
|
|
<td>206.124.146.177</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2003-01-31 22:50:51 +01:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><font color="#660066"><b><a name="ProxyArp"></a>
|
|
|
|
|
|
</b></font>/etc/shorewall/proxyarp</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>If you want to use proxy ARP on an entire sub-network,
|
|
|
|
|
|
I suggest that you look
|
|
|
|
|
|
at <a
|
|
|
|
|
|
href="http://www.tldp.org/HOWTO/mini/Proxy-ARP-Subnet/">
|
|
|
|
|
|
http://www.tldp.org/HOWTO/mini/Proxy-ARP-Subnet/</a>.
|
|
|
|
|
|
If you decide to use the technique
|
|
|
|
|
|
described in that
|
|
|
|
|
|
HOWTO, you can set
|
|
|
|
|
|
the proxy_arp flag
|
|
|
|
|
|
for an interface
|
|
|
|
|
|
(/proc/sys/net/ipv4/conf/<i><interface></i>/proxy_arp) by
|
|
|
|
|
|
including the <b> proxyarp</b> option
|
|
|
|
|
|
in the interface's
|
|
|
|
|
|
record in
|
|
|
|
|
|
<a href="#Interfaces">
|
|
|
|
|
|
/etc/shorewall/interfaces</a>.
|
|
|
|
|
|
When using Proxy ARP sub-netting,
|
|
|
|
|
|
you do <u>NOT</u> include
|
|
|
|
|
|
any entries in /etc/shorewall/proxyarp.
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>The /etc/shorewall/proxyarp file is used to define <a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
href="ProxyARP.htm">Proxy ARP</a>. The file is
|
|
|
|
|
|
typically used for
|
|
|
|
|
|
enabling Proxy ARP on a
|
|
|
|
|
|
small set of systems
|
|
|
|
|
|
since you need
|
|
|
|
|
|
one entry in this file for each
|
|
|
|
|
|
system using proxy ARP. Columns
|
|
|
|
|
|
are:</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> ADDRESS</b> - address of the
|
2003-03-22 01:25:40 +01:00
|
|
|
|
system.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> INTERFACE</b> - the interface
|
|
|
|
|
|
that connects to the system. If the interface is obvious
|
2003-03-22 01:25:40 +01:00
|
|
|
|
from the subnetting, you may enter "-" in this column.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> EXTERNAL</b> - the external
|
|
|
|
|
|
interface that you want to honor ARP requests for the
|
2003-03-22 01:25:40 +01:00
|
|
|
|
ADDRESS specified in the first column.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>HAVEROUTE</b> - If
|
|
|
|
|
|
you already have
|
|
|
|
|
|
a route through
|
|
|
|
|
|
INTERFACE to
|
|
|
|
|
|
ADDRESS,
|
|
|
|
|
|
this column should contain "Yes"
|
|
|
|
|
|
or "yes". If you want Shorewall to add
|
|
|
|
|
|
the route, the
|
|
|
|
|
|
column should contain
|
|
|
|
|
|
"No"
|
|
|
|
|
|
or "no".</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><font color="#cc6666"><b>Note: After you have made a change to the /etc/shorewall/proxyarp
|
|
|
|
|
|
file, you may need to flush the ARP cache of all routers
|
|
|
|
|
|
on the LAN segment connected to the interface specified in the
|
|
|
|
|
|
EXTERNAL column of the change/added entry(s). If you are having
|
|
|
|
|
|
problems communicating between an individual host (A) on that
|
|
|
|
|
|
segment and a system whose entry has changed, you may need to
|
2003-03-22 01:25:40 +01:00
|
|
|
|
flush the ARP cache on host A as well.</b></font></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><font color="#cc6666"><b>ISPs typically have ARP configured with long TTL
|
|
|
|
|
|
(hours!) so if your ISPs router has a stale cache entry (as seen using "tcpdump
|
|
|
|
|
|
-nei <external interface> host <IP addr>"), it may take a long
|
|
|
|
|
|
while to time out. I personally have had to contact my ISP and ask them
|
|
|
|
|
|
to delete a stale entry in order to restore a system to working order after
|
|
|
|
|
|
changing my proxy ARP settings. </b></font></p>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b>Example: </b> You have public IP addresses 155.182.235.0/28. You
|
|
|
|
|
|
configure your firewall as follows:</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>eth0 - 155.186.235.1 (internet connection)</li>
|
|
|
|
|
|
<li>eth1 - 192.168.9.0/24 (masqueraded
|
2003-03-22 01:25:40 +01:00
|
|
|
|
local systems)</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>eth2 - 192.168.10.1 (interface to
|
2003-03-22 01:25:40 +01:00
|
|
|
|
your DMZ)</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p> In your DMZ, you want to install a Web/FTP server with public address
|
|
|
|
|
|
155.186.235.4. On the Web server, you subnet just like the
|
|
|
|
|
|
firewall's eth0 and you configure 155.186.235.1 as the default
|
|
|
|
|
|
gateway. In your /etc/shorewall/proxyarp file, you will have:</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="2" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b> ADDRESS</b></td>
|
|
|
|
|
|
<td><b> INTERFACE</b></td>
|
|
|
|
|
|
<td><b> EXTERNAL</b></td>
|
|
|
|
|
|
<td><b>HAVEROUTE</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>155.186.235.4</td>
|
|
|
|
|
|
<td>eth2</td>
|
|
|
|
|
|
<td>eth0</td>
|
|
|
|
|
|
<td>No</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> Note: You may want to configure the servers in your DMZ with a subnet
|
|
|
|
|
|
that is smaller than the subnet of your internet interface.
|
2003-03-22 01:25:40 +01:00
|
|
|
|
See the Proxy ARP Subnet Mini HOWTO (<a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
href="http://www.tldp.org/HOWTO/mini/Proxy-ARP-Subnet/">http://www.tldp.org/HOWTO/mini/Proxy-ARP-Subnet/</a>)
|
|
|
|
|
|
for details. In this case you will want to place "Yes" in
|
|
|
|
|
|
the HAVEROUTE column.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p><font color="#ff6633"><b>Warning: </b></font>Do not use Proxy ARP and FreeS/Wan
|
|
|
|
|
|
on the same system unless you are prepared to suffer the consequences.
|
|
|
|
|
|
If you start or restart Shorewall with an IPSEC tunnel active,
|
|
|
|
|
|
the proxied IP addresses are mistakenly assigned to the IPSEC
|
|
|
|
|
|
tunnel device (ipsecX) rather than to the interface that you
|
|
|
|
|
|
specify in the INTERFACE column of /etc/shorewall/proxyarp. I haven't
|
|
|
|
|
|
had the time to debug this problem so I can't say if it is a bug
|
2003-03-07 00:41:31 +01:00
|
|
|
|
in the Kernel or in FreeS/Wan. </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>You <b>might</b> be able to work around this problem using the following
|
2003-03-22 01:25:40 +01:00
|
|
|
|
(I haven't tried it):</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>In /etc/shorewall/init, include:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<p> qt service ipsec stop</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>In /etc/shorewall/start, include:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<p> qt service ipsec start</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<h2><font color="#660066"><b><a name="NAT"></a>
|
|
|
|
|
|
</b></font>/etc/shorewall/nat</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>The /etc/shorewall/nat file is used to define static NAT. There is one
|
|
|
|
|
|
entry in the file for each static NAT relationship that
|
|
|
|
|
|
you wish to define. In order to make use of this feature, you
|
|
|
|
|
|
must have <a href="#NatEnabled">NAT enabled</a> .</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> <font
|
2003-04-13 17:28:32 +02:00
|
|
|
|
color="#ff0000"> <b>IMPORTANT: If all you want to do
|
|
|
|
|
|
is forward ports to
|
|
|
|
|
|
servers behind your firewall, you
|
|
|
|
|
|
do NOT want to use
|
|
|
|
|
|
static NAT. Port
|
|
|
|
|
|
forwarding can be
|
|
|
|
|
|
accomplished
|
|
|
|
|
|
with simple entries in
|
|
|
|
|
|
the <a href="#Rules"> rules
|
|
|
|
|
|
file</a>. Also, in most
|
|
|
|
|
|
cases <a href="#ProxyArp">
|
|
|
|
|
|
Proxy ARP</a>
|
|
|
|
|
|
provides a
|
|
|
|
|
|
superior solution
|
|
|
|
|
|
to static NAT because
|
|
|
|
|
|
the internal systems
|
|
|
|
|
|
are accessed
|
|
|
|
|
|
using the same IP address internally
|
|
|
|
|
|
and externally.</b></font></p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>Columns in an entry are:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> EXTERNAL</b> - External IP
|
|
|
|
|
|
address - <u>This should NOT be the primary IP address
|
2003-03-22 01:25:40 +01:00
|
|
|
|
of the interface named in the next column.</u></li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> INTERFACE</b> - Interface
|
|
|
|
|
|
that you want the EXTERNAL IP address to appear on. Beginning
|
|
|
|
|
|
with Shorewall version 1.3.14, if you have set ADD_IP_ALIASES=Yes in
|
|
|
|
|
|
<a href="#Conf">/etc/shorewall/shorewall.conf</a>, <20>you can specify an
|
|
|
|
|
|
alias label of the form <i>interfacename:digit </i>(e.g., eth0:0) and
|
|
|
|
|
|
Shorewall will create the alias with that label. Alias labels created
|
|
|
|
|
|
in this way allow the alias to be visible to the ipconfig utility.
|
|
|
|
|
|
<b>THAT IS THE ONLY THING THAT THIS LABEL IS GOOD FOR AND IT MAY NOT
|
|
|
|
|
|
APPEAR ANYWHERE ELSE IN YOUR SHOREWALL CONFIGURATION.</b><EFBFBD></li>
|
|
|
|
|
|
<li><b> INTERNAL </b> - Internal IP
|
2003-03-22 01:25:40 +01:00
|
|
|
|
address.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>ALL
|
|
|
|
|
|
INTERFACES</b>
|
|
|
|
|
|
- If Yes
|
|
|
|
|
|
or yes (or
|
|
|
|
|
|
left
|
|
|
|
|
|
empty),
|
|
|
|
|
|
NAT will be effective
|
|
|
|
|
|
from all hosts.
|
|
|
|
|
|
If No or no
|
|
|
|
|
|
then NAT
|
|
|
|
|
|
will be
|
|
|
|
|
|
effective
|
|
|
|
|
|
only
|
|
|
|
|
|
through the interface
|
|
|
|
|
|
named in the
|
|
|
|
|
|
INTERFACE column.</li>
|
|
|
|
|
|
<li><b>LOCAL</b> - If Yes or yes and
|
|
|
|
|
|
the ALL INTERFACES column contains Yes or yes, NAT will
|
|
|
|
|
|
be effective from the firewall system. <b>Note: </b>For
|
|
|
|
|
|
this to work, you must be running kernel 2.4.19 or later and
|
|
|
|
|
|
iptables 1.2.6a or later and you must have enabled <b>CONFIG_IP_NF_NAT_LOCAL</b>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
in your kernel.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><b><a href="NAT.htm"> Look here for additional information and an example.</a>
|
|
|
|
|
|
</b></p>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><font color="#660066"><a name="Tunnels"></a>
|
|
|
|
|
|
</font>/etc/shorewall/tunnels</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p> The /etc/shorewall/tunnels file allows you to define IPSec, GRE, IPIP,
|
|
|
|
|
|
<a href="http://openvpn.sourceforge.net/">OpenVPN</a> and PPTP
|
|
|
|
|
|
tunnels with end-points on your firewall. To use ipsec, you must
|
2003-03-22 01:25:40 +01:00
|
|
|
|
install version 1.9, 1.91 or the current <a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
href="http://www.xs4all.nl/%7Efreeswan/">FreeS/WAN</a> development snapshot.
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p> Note: For kernels 2.4.4 and above, you will need to use version 1.91
|
|
|
|
|
|
or a development snapshot as patching with version 1.9
|
2003-03-07 00:41:31 +01:00
|
|
|
|
results in kernel compilation errors.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><b><a href="IPSEC.htm"> Instructions for setting up IPSEC tunnels may
|
|
|
|
|
|
be found here,</a></b> <b><a href="IPIP.htm">instructions
|
2003-03-22 01:25:40 +01:00
|
|
|
|
for IPIP and GRE tunnels are here</a></b>, <b><a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
href="OPENVPN.html">instructions for OpenVPN tunnels are here</a></b>, and
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<b><a href="PPTP.htm">instructions for PPTP tunnels are here</a>.</b></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<h2><a name="Conf"></a>/etc/shorewall/shorewall.conf</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> This file is used to set the following firewall parameters:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>CLEAR_TC</b> - Added at
|
2003-03-22 01:25:40 +01:00
|
|
|
|
version 1.3.13<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
If this option is set to 'No' then Shorewall won't clear the
|
|
|
|
|
|
current traffic control rules during [re]start. This setting is intended
|
|
|
|
|
|
for use by people that prefer to configure traffic shaping when the network
|
|
|
|
|
|
interfaces come up rather than when the firewall is started. If that
|
|
|
|
|
|
is what you want to do, set TC_ENABLED=Yes and CLEAR_TC=No and do not supply
|
|
|
|
|
|
an /etc/shorewall/tcstart file. That way, your traffic shaping rules
|
|
|
|
|
|
can still use the 'fwmark' classifier based on packet marking defined
|
|
|
|
|
|
in /etc/shorewall/tcrules. If not specified, CLEAR_TC=Yes is assumed.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>MARK_IN_FORWARD_CHAIN </b>- Added at version 1.3.12<br>
|
|
|
|
|
|
If your kernel has a FORWARD chain in the mangle table,
|
|
|
|
|
|
you may set MARK_IN_FORWARD_CHAIN=Yes to cause the marking specified
|
|
|
|
|
|
in the <a href="traffic_shaping.htm#tcrules">tcrules file</a> to occur
|
|
|
|
|
|
in that chain rather than in the PREROUTING chain. This permits you
|
|
|
|
|
|
to mark inbound traffic based on its destination address when SNAT
|
|
|
|
|
|
or Masquerading are in use. To determine if your kernel has a FORWARD
|
|
|
|
|
|
chain in the mangle table, use the "/sbin/shorewall show mangle" command;
|
|
|
|
|
|
if a FORWARD chain is displayed then your kernel will support this
|
|
|
|
|
|
option. If this option is not specified or if it is given the empty value
|
|
|
|
|
|
(e.g., MARK_IN_FORWARD_CHAIN="") then MARK_IN_FORWARD_CHAIN=No is assumed.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>RFC1918_LOG_LEVEL - </b>Added at version 1.3.12<br>
|
|
|
|
|
|
This parameter determines the level at which packets
|
|
|
|
|
|
logged under the <a href="Documentation.htm#rfc1918">'norfc1918'
|
2003-03-22 01:25:40 +01:00
|
|
|
|
mechanism </a> are logged. The value must be a valid <a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
href="shorewall_logging.html">syslog level</a> and if no level is given,
|
|
|
|
|
|
then info is assumed. Prior to Shorewall version 1.3.12, these packets
|
2003-03-22 01:25:40 +01:00
|
|
|
|
are always logged at the info level.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>TCP_FLAGS_DISPOSITION - </b>Added in Version
|
2003-03-07 00:41:31 +01:00
|
|
|
|
1.3.11<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Determines the disposition of TCP packets that fail
|
|
|
|
|
|
the checks enabled by the <a href="#Interfaces%5C">tcpflags</a>
|
|
|
|
|
|
interface option and must have a value of ACCEPT (accept the packet),
|
|
|
|
|
|
REJECT (send an RST response) or DROP (ignore the packet). If not
|
|
|
|
|
|
set or if set to the empty value (e.g., TCP_FLAGS_DISPOSITION="") then
|
|
|
|
|
|
TCP_FLAGS_DISPOSITION=DROP is assumed.</li>
|
|
|
|
|
|
<li><b>TCP_FLAGS_LOG_LEVEL - </b>Added in Version
|
2003-03-22 01:25:40 +01:00
|
|
|
|
1.3.11<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Determines the <a
|
|
|
|
|
|
href="shorewall_logging.html">syslog level</a> for logging packets
|
|
|
|
|
|
that fail the checks enabled by the <a href="#Interfaces">tcpflags</a>
|
|
|
|
|
|
interface option.The value must be a valid syslogd log level.
|
|
|
|
|
|
If you don't want to log these packets, set to the empty value
|
|
|
|
|
|
(e.g., TCP_FLAGS_LOG_LEVEL="").<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>MACLIST_DISPOSITION </b>- Added in Version
|
2003-03-22 01:25:40 +01:00
|
|
|
|
1.3.10<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Determines the disposition of connections requests
|
|
|
|
|
|
that fail <a href="MAC_Validation.html">MAC Verification</a> and
|
|
|
|
|
|
must have the value ACCEPT (accept the connection request anyway), REJECT
|
|
|
|
|
|
(reject the connection request) or DROP (ignore the connection request).
|
|
|
|
|
|
If not set or if set to the empty value (e.g., MACLIST_DISPOSITION="")
|
2003-03-22 01:25:40 +01:00
|
|
|
|
then MACLIST_DISPOSITION=REJECT is assumed.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>MACLIST_LOG_LEVEL </b>- Added in Version
|
2003-03-22 01:25:40 +01:00
|
|
|
|
1.3.10<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Determines the <a
|
|
|
|
|
|
href="shorewall_logging.html">syslog level</a> for logging connection
|
|
|
|
|
|
requests that fail <a href="MAC_Validation.html">MAC Verification</a>.
|
|
|
|
|
|
The value must be a valid syslogd log level. If you don't want
|
|
|
|
|
|
to log these connection requests, set to the empty value (e.g.,
|
2003-03-07 00:41:31 +01:00
|
|
|
|
MACLIST_LOG_LEVEL="").<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>NEWNOTSYN </b>- Added in Version 1.3.8<br>
|
|
|
|
|
|
When set to "Yes" or "yes", Shorewall will
|
|
|
|
|
|
filter TCP packets that are not part of an established connention
|
|
|
|
|
|
and that are not SYN packets (SYN flag on - ACK flag off). If set
|
|
|
|
|
|
to "No", Shorewall will silently drop such packets. If not set
|
|
|
|
|
|
or set to the empty value (e.g., "NEWNOTSYN="), NEWNOTSYN=No is
|
|
|
|
|
|
assumed.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
If you have a HA setup with failover to another
|
|
|
|
|
|
firewall, you should have NEWNOTSYN=Yes on both firewalls.
|
2003-03-07 00:41:31 +01:00
|
|
|
|
You should also select NEWNOTSYN=Yes if you have asymmetric routing.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>LOGNEWNOTSYN</b> - Added in Version
|
2003-03-22 01:25:40 +01:00
|
|
|
|
1.3.6<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Beginning with version 1.3.6, Shorewall
|
|
|
|
|
|
drops non-SYN TCP packets that are not part of an existing
|
|
|
|
|
|
connection. If you would like to log these packets, set
|
|
|
|
|
|
LOGNEWNOTSYN to the <a href="shorewall_logging.html">syslog level</a>
|
|
|
|
|
|
at which you want the packets logged. Example: LOGNEWNOTSYN=ULOG|<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
<b>Note: </b>Packets logged under this
|
|
|
|
|
|
option are usually the result of broken remote IP stacks
|
|
|
|
|
|
rather than the result of any sort of attempt to breach your
|
2003-03-22 01:25:40 +01:00
|
|
|
|
firewall.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>DETECT_DNAT_ADDRS</b>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
- Added in Version 1.3.4<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
If set to "Yes" or "yes", Shorewall will detect the IP address(es)
|
|
|
|
|
|
of the interface(es) to the source zone and will include this
|
|
|
|
|
|
(these) address(es) in DNAT rules as the original destination
|
|
|
|
|
|
IP address. If set to "No" or "no", Shorewall will not detect this
|
|
|
|
|
|
(these) address(es) and any destination IP address will match the
|
|
|
|
|
|
DNAT rule. If not specified or empty, "DETECT_DNAT_ADDRS=Yes" is
|
2003-03-07 00:41:31 +01:00
|
|
|
|
assumed.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b></b><b>MULTIPORT</b> - Added in
|
2003-03-22 01:25:40 +01:00
|
|
|
|
Version 1.3.2<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
If set to "Yes" or "yes", Shorewall
|
|
|
|
|
|
will use the Netfilter multiport facility. In order to
|
|
|
|
|
|
use this facility, your kernel must have multiport support
|
|
|
|
|
|
(CONFIG_IP_NF_MATCH_MULTIPORT). When this support is used, Shorewall
|
|
|
|
|
|
will generate a single rule from each record in the /etc/shorewall/rules
|
2003-03-07 00:41:31 +01:00
|
|
|
|
file that meets these criteria:<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li>No port range(s) specified</li>
|
|
|
|
|
|
<li>Specifies 15 or fewer ports</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Rules not meeting those criteria will continue to generate an individual
|
2003-03-22 01:25:40 +01:00
|
|
|
|
rule for each listed port or port range. </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>NAT_BEFORE_RULES</b><br>
|
|
|
|
|
|
If set to "No" or "no", port forwarding
|
|
|
|
|
|
rules can override the contents of the <a href="#NAT">/etc/shorewall/nat</a>
|
|
|
|
|
|
file. If set to "Yes" or "yes", port forwarding rules cannot
|
|
|
|
|
|
override static NAT. If not set or set to an empty value,
|
|
|
|
|
|
"Yes" is assumed.</li>
|
|
|
|
|
|
<li><b>FW<br>
|
|
|
|
|
|
</b>This
|
|
|
|
|
|
parameter specifies the
|
|
|
|
|
|
name of the
|
|
|
|
|
|
firewall zone.
|
|
|
|
|
|
If not set or
|
|
|
|
|
|
if set
|
|
|
|
|
|
to an empty string, the value
|
|
|
|
|
|
"fw" is assumed.</li>
|
|
|
|
|
|
<li><b>SUBSYSLOCK</b><br>
|
|
|
|
|
|
This parameter should be set to
|
|
|
|
|
|
the name of a file that the firewall should create if
|
|
|
|
|
|
it starts successfully and remove when it stops. Creating
|
|
|
|
|
|
and removing this file allows Shorewall to work with your distribution's
|
|
|
|
|
|
initscripts. For RedHat, this should be set to /var/lock/subsys/shorewall.
|
|
|
|
|
|
For Debian, the value is /var/state/shorewall and in LEAF it
|
|
|
|
|
|
is /var/run/shorwall. Example: SUBSYSLOCK=/var/lock/subsys/shorewall.</li>
|
|
|
|
|
|
<li><b> STATEDIR</b><br>
|
|
|
|
|
|
This parameter specifies the name
|
|
|
|
|
|
of a directory where Shorewall stores state information.
|
|
|
|
|
|
If the directory doesn't exist when Shorewall starts, it
|
|
|
|
|
|
will create the directory. Example: STATEDIR=/tmp/shorewall.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
<b>NOTE:</b> If you change the STATEDIR
|
|
|
|
|
|
variable while the firewall is running, create the new
|
|
|
|
|
|
directory if necessary then copy the contents of the old
|
|
|
|
|
|
directory to the new directory. </li>
|
|
|
|
|
|
<li><b>MODULESDIR</b><br>
|
|
|
|
|
|
This parameter specifies the directory
|
|
|
|
|
|
where your kernel netfilter modules may be found. If
|
|
|
|
|
|
you leave the variable empty, Shorewall will supply the value
|
|
|
|
|
|
"/lib/modules/`uname -r`/kernel/net/ipv4/netfilter.</li>
|
|
|
|
|
|
<li><b> LOGRATE </b> and <b> LOGBURST</b><br>
|
|
|
|
|
|
These parameters set the match
|
|
|
|
|
|
rate and initial burst size for logged packets. Please
|
|
|
|
|
|
see the iptables man page for a description of the behavior
|
|
|
|
|
|
of these parameters (the iptables option --limit is set by LOGRATE
|
|
|
|
|
|
and --limit-burst is set by LOGBURST). If both parameters are
|
|
|
|
|
|
set empty, no rate-limiting will occur.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
Example:<br>
|
|
|
|
|
|
LOGRATE=10/minute<br>
|
|
|
|
|
|
LOGBURST=5<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>LOGFILE</b><br>
|
|
|
|
|
|
This parameter
|
|
|
|
|
|
tells the /sbin/shorewall
|
|
|
|
|
|
program where
|
|
|
|
|
|
to look for
|
|
|
|
|
|
Shorewall
|
|
|
|
|
|
messages when processing
|
|
|
|
|
|
the "show log", "monitor",
|
|
|
|
|
|
"status" and
|
|
|
|
|
|
"hits" commands.
|
|
|
|
|
|
If not assigned
|
|
|
|
|
|
or if assigned
|
|
|
|
|
|
an empty
|
|
|
|
|
|
value,
|
|
|
|
|
|
/var/log/messages
|
|
|
|
|
|
is
|
2003-03-22 01:25:40 +01:00
|
|
|
|
assumed.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>NAT_ENABLED</b><br>
|
|
|
|
|
|
This parameter determines whether
|
|
|
|
|
|
Shorewall supports NAT operations. NAT operations
|
|
|
|
|
|
include:<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
Static NAT<br>
|
|
|
|
|
|
Port Forwarding<br>
|
|
|
|
|
|
Port Redirection<br>
|
|
|
|
|
|
Masquerading<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
If the parameter has no value
|
|
|
|
|
|
or has a value of "Yes" or "yes" then NAT is enabled.
|
|
|
|
|
|
If the parameter has a value of "no" or "No" then NAT is
|
|
|
|
|
|
disabled.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b> MANGLE_ENABLED</b><br>
|
|
|
|
|
|
This parameter determines if packet
|
|
|
|
|
|
mangling is enabled. If the parameter has no value or
|
|
|
|
|
|
has a value of "Yes" or "yes" than packet mangling is enabled.
|
|
|
|
|
|
If the parameter has a value of "no" or "No" then packet
|
|
|
|
|
|
mangling is disabled. If packet mangling is disabled, the
|
|
|
|
|
|
/etc/shorewall/tos file is ignored.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b> IP_FORWARDING</b><br>
|
|
|
|
|
|
This parameter determines whether
|
|
|
|
|
|
Shorewall enables or disables IPV4 Packet Forwarding
|
2003-03-22 01:25:40 +01:00
|
|
|
|
(/proc/sys/net/ipv4/ip_forward). Possible values are:<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
On or on - packet forwarding
|
2003-03-22 01:25:40 +01:00
|
|
|
|
will be enabled.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Off or off - packet forwarding
|
2003-03-22 01:25:40 +01:00
|
|
|
|
will be disabled.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Keep or keep - Shorewall will
|
2003-03-22 01:25:40 +01:00
|
|
|
|
neither enable nor disable packet forwarding.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
If this variable is not set or
|
|
|
|
|
|
is given an empty value (IP_FORWARD="") then IP_FORWARD=On
|
|
|
|
|
|
is assumed.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>ADD_IP_ALIASES</b><br>
|
|
|
|
|
|
This parameter determines whether
|
|
|
|
|
|
Shorewall automatically adds the
|
|
|
|
|
|
<i>external </i>address(es) in <a
|
|
|
|
|
|
href="#NAT">/etc/shorewall/nat</a> . If the variable is
|
|
|
|
|
|
set to "Yes" or "yes" then Shorewall automatically adds these aliases.
|
|
|
|
|
|
If it is set to "No" or "no", you must add these aliases yourself
|
|
|
|
|
|
using your distribution's network configuration tools. <b>RESTRICTION:
|
|
|
|
|
|
</b>Shorewall can only add addresses to the first subnetwork configured
|
|
|
|
|
|
on an interface.<br>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<br>
|
|
|
|
|
|
If this variable is not set or
|
2003-04-13 17:28:32 +02:00
|
|
|
|
is given an empty value (ADD_IP_ALIASES="") then ADD_IP_ALIASES=Yes
|
2003-03-22 01:25:40 +01:00
|
|
|
|
is assumed.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>ADD_SNAT_ALIASES</b><br>
|
|
|
|
|
|
This parameter determines whether Shorewall
|
2003-03-22 01:25:40 +01:00
|
|
|
|
automatically adds the SNAT <i> ADDRESS </i>in <a
|
2003-04-13 17:28:32 +02:00
|
|
|
|
href="#Masq">/etc/shorewall/masq</a>. If the variable is
|
|
|
|
|
|
set to "Yes" or "yes" then Shorewall automatically adds these
|
|
|
|
|
|
addresses. If it is set to "No" or "no", you must add these addresses
|
|
|
|
|
|
yourself using your distribution's network configuration tools.
|
|
|
|
|
|
<b>RESTRICTION: </b>Shorewall can only add addresses to the first subnetwork
|
|
|
|
|
|
configured on an interface.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
If this variable is not set or
|
|
|
|
|
|
is given an empty value (ADD_SNAT_ALIASES="") then
|
|
|
|
|
|
ADD_SNAT_ALIASES=No is assumed.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>LOGUNCLEAN</b><br>
|
|
|
|
|
|
This parameter
|
|
|
|
|
|
determines the logging
|
|
|
|
|
|
level of
|
|
|
|
|
|
mangled/invalid
|
|
|
|
|
|
packets
|
|
|
|
|
|
controlled by
|
|
|
|
|
|
the '<a href="#Unclean">dropunclean
|
|
|
|
|
|
and logunclean</a>'
|
|
|
|
|
|
interface
|
|
|
|
|
|
options. If
|
|
|
|
|
|
LOGUNCLEAN is empty (LOGUNCLEAN=) then
|
|
|
|
|
|
packets selected by
|
|
|
|
|
|
'dropclean' are dropped
|
|
|
|
|
|
silently
|
|
|
|
|
|
('logunclean'
|
|
|
|
|
|
packets are
|
|
|
|
|
|
logged under the 'info' log
|
|
|
|
|
|
level). Otherwise, these packets
|
|
|
|
|
|
are logged at the
|
|
|
|
|
|
specified level
|
|
|
|
|
|
(Example:
|
|
|
|
|
|
LOGUNCLEAN=debug).</li>
|
|
|
|
|
|
<li><b>BLACKLIST_DISPOSITION</b><br>
|
|
|
|
|
|
This parameter
|
|
|
|
|
|
determines the disposition
|
|
|
|
|
|
of packets from
|
|
|
|
|
|
blacklisted
|
|
|
|
|
|
hosts. It may
|
|
|
|
|
|
have the value DROP if the packets
|
|
|
|
|
|
are to be dropped or
|
|
|
|
|
|
REJECT if the
|
|
|
|
|
|
packets are to
|
|
|
|
|
|
be replied
|
|
|
|
|
|
with an ICMP
|
|
|
|
|
|
port
|
|
|
|
|
|
unreachable
|
|
|
|
|
|
reply or a
|
|
|
|
|
|
TCP RST (tcp only). If you do not assign
|
|
|
|
|
|
a value or if
|
|
|
|
|
|
you assign an empty value
|
|
|
|
|
|
then DROP is
|
|
|
|
|
|
assumed.</li>
|
|
|
|
|
|
<li><b>BLACKLIST_LOGLEVEL</b><br>
|
|
|
|
|
|
This paremter
|
|
|
|
|
|
determines if packets from
|
|
|
|
|
|
blacklisted
|
|
|
|
|
|
hosts are
|
|
|
|
|
|
logged and it
|
|
|
|
|
|
determines the syslog
|
|
|
|
|
|
level that they are to be logged
|
|
|
|
|
|
at. Its value
|
|
|
|
|
|
is a <a href="shorewall_logging.html">syslog level</a>
|
|
|
|
|
|
(Example:
|
|
|
|
|
|
BLACKLIST_LOGLEVEL=debug). If
|
|
|
|
|
|
you do not assign a value or if you
|
|
|
|
|
|
assign an empty value
|
|
|
|
|
|
then packets
|
|
|
|
|
|
from blacklisted
|
|
|
|
|
|
hosts are not
|
|
|
|
|
|
logged.</li>
|
|
|
|
|
|
<li><b>CLAMPMSS</b><br>
|
|
|
|
|
|
This parameter
|
|
|
|
|
|
enables the TCP Clamp
|
|
|
|
|
|
MSS to PMTU
|
|
|
|
|
|
feature of
|
|
|
|
|
|
Netfilter and
|
|
|
|
|
|
is usually
|
|
|
|
|
|
required when
|
|
|
|
|
|
your internet connection
|
|
|
|
|
|
is through PPPoE
|
|
|
|
|
|
or PPTP. If set
|
|
|
|
|
|
to "Yes"
|
|
|
|
|
|
or "yes",
|
|
|
|
|
|
the feature is
|
|
|
|
|
|
enabled. If
|
|
|
|
|
|
left blank or
|
|
|
|
|
|
set to
|
|
|
|
|
|
"No"
|
|
|
|
|
|
or
|
|
|
|
|
|
"no",
|
|
|
|
|
|
the feature is
|
|
|
|
|
|
not enabled.
|
|
|
|
|
|
Note: This option requires
|
|
|
|
|
|
CONFIG_IP_NF_TARGET_TCPMSS
|
|
|
|
|
|
<a href="kernel.htm">in your kernel</a>.</li>
|
|
|
|
|
|
<li><b>ROUTE_FILTER</b><br>
|
|
|
|
|
|
If this parameter is given the value
|
|
|
|
|
|
"Yes" or "yes" then route filtering (anti-spoofing) is
|
2003-03-22 01:25:40 +01:00
|
|
|
|
enabled on all network interfaces. The default value is "no".</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<h2><a name="modules"></a> /etc/shorewall/modules Configuration</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>The file /etc/shorewall/modules contains commands for loading the kernel
|
|
|
|
|
|
modules required by Shorewall-defined firewall rules. Shorewall
|
|
|
|
|
|
will source this file during start/restart provided that
|
|
|
|
|
|
it exists and that the directory specified by the MODULESDIR
|
|
|
|
|
|
parameter exists (see <a href="#Conf">/etc/shorewall/shorewall.conf</a>
|
2003-03-07 00:41:31 +01:00
|
|
|
|
above).</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>The file that is released with Shorewall calls the Shorewall function
|
2003-03-22 01:25:40 +01:00
|
|
|
|
"loadmodule" for the set of modules that I load.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>The <i>loadmodule</i> function is called as follows:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
<p>loadmodule <i><modulename> </i>[
|
|
|
|
|
|
<i> <module parameters> </i>]</p>
|
|
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>where</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<p><i><modulename> </i></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
<p>is the name of the modules without the trailing ".o" (example
|
|
|
|
|
|
ip_conntrack).</p>
|
|
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p><i> <module parameters></i></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Optional parameters to the insmod utility.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> The function determines if the module named by <i><modulename>
|
|
|
|
|
|
</i> is already loaded and if not then the function determines
|
|
|
|
|
|
if the ".o" file corresponding to the module exists in the
|
|
|
|
|
|
<i>moduledirectory</i>; if so, then the following command
|
2003-03-22 01:25:40 +01:00
|
|
|
|
is executed:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
<p> insmod <i>moduledirectory</i>/<i><modulename></i>.o <i><module
|
2003-03-22 01:25:40 +01:00
|
|
|
|
parameters></i></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> If the file doesn't exist, the function determines of the ".o.gz"
|
|
|
|
|
|
file corresponding to the module exists in the <i>moduledirectory</i>. If
|
|
|
|
|
|
it does, the function assumes that the running configuration supports compressed
|
|
|
|
|
|
modules and execute the following command:</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
<p> insmod <i>moduledirectory/<modulename>.</i>o.gz <<i>module
|
2003-03-22 01:25:40 +01:00
|
|
|
|
parameters></i></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><a name="TOS"></a> /etc/shorewall/tos Configuration</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p> The /etc/shorewall/tos file allows you to set the Type of Service field
|
|
|
|
|
|
in packet headers based on packet source, packet destination,
|
|
|
|
|
|
protocol, source port and destination port. In order for
|
2003-03-22 01:25:40 +01:00
|
|
|
|
this file to be processed by Shorewall, you must have <a
|
2003-01-14 18:18:42 +01:00
|
|
|
|
href="#MangleEnabled">mangle support enabled</a> .</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Entries in the file have the following columns:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> SOURCE</b> -- The source zone.
|
|
|
|
|
|
May be qualified by following the zone name with a colon
|
|
|
|
|
|
(":") and either an IP address, an IP subnet, a MAC address
|
|
|
|
|
|
in <a href="#MAC">Shorewall Format</a> or the name of an
|
|
|
|
|
|
interface. This column may also contain the <a href="#FW">name of
|
|
|
|
|
|
the firewall</a>
|
|
|
|
|
|
zone to
|
|
|
|
|
|
indicate packets originating on the firewall itself or "all" to
|
|
|
|
|
|
indicate any source.</li>
|
|
|
|
|
|
<li><b> DEST</b> -- The destination
|
|
|
|
|
|
zone. May be qualified by following the zone name with
|
|
|
|
|
|
a colon (":") and either an IP address or an IP subnet. Because
|
|
|
|
|
|
packets are marked prior to routing, you may not specify
|
|
|
|
|
|
the name of an interface. This column may also contain "all"
|
|
|
|
|
|
to indicate any destination.</li>
|
|
|
|
|
|
<li><b> PROTOCOL</b> -- The name of
|
2003-03-22 01:25:40 +01:00
|
|
|
|
a protocol in /etc/protocols or the protocol's number.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b> SOURCE PORT(S)</b> -- The
|
|
|
|
|
|
source port or a port range. For all ports, place a
|
|
|
|
|
|
hyphen ("-") in this column.</li>
|
|
|
|
|
|
<li><b> DEST PORT(S)</b> -- The destination
|
|
|
|
|
|
port or a port range. To indicate all ports, place a hyphen
|
|
|
|
|
|
("-") in this column.</li>
|
|
|
|
|
|
<li><b> TOS</b> -- The type of service.
|
2003-03-22 01:25:40 +01:00
|
|
|
|
Must be one of the following:</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Minimize-Delay (16)<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
Maximize-Throughput (8)<br>
|
|
|
|
|
|
Maximize-Reliability (4)<br>
|
|
|
|
|
|
Minimize-Cost (2)<br>
|
|
|
|
|
|
Normal-Service (0)</p>
|
|
|
|
|
|
</blockquote>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</blockquote>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p> The /etc/shorewall/tos file that is included with Shorewall contains
|
2003-03-22 01:25:40 +01:00
|
|
|
|
the following entries.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="2" cellpadding="2" style="border-collapse: collapse;">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
|
|
|
<td><b>PROTOCOL</b></td>
|
|
|
|
|
|
<td><b>SOURCE<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
|
|
<td><b>DEST PORT(S)</b></td>
|
|
|
|
|
|
<td><b>TOS</b></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>ssh</td>
|
|
|
|
|
|
<td>16</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ssh</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>16</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>ftp</td>
|
|
|
|
|
|
<td>16</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ftp</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>16</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>ftp-data</td>
|
|
|
|
|
|
<td>8</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>all</td>
|
|
|
|
|
|
<td>tcp</td>
|
|
|
|
|
|
<td>ftp-data</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
<td>8</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b>WARNING: </b>Users have reported that odd routing problems result from
|
|
|
|
|
|
adding the ESP and AH protocols to the /etc/shorewall/tos
|
2003-03-07 00:41:31 +01:00
|
|
|
|
file. </p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<h2><a name="Blacklist"></a>/etc/shorewall/blacklist</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Each line in
|
|
|
|
|
|
/etc/shorewall/blacklist
|
|
|
|
|
|
contains
|
|
|
|
|
|
an IP
|
|
|
|
|
|
address, a MAC address in <a href="#MAC">Shorewall Format</a>
|
|
|
|
|
|
or
|
|
|
|
|
|
subnet
|
|
|
|
|
|
address. Example:</p>
|
|
|
|
|
|
|
2003-01-31 22:50:51 +01:00
|
|
|
|
<pre> 130.252.100.69<br> 206.124.146.0/24</pre>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Packets <u><b>from</b></u>
|
|
|
|
|
|
hosts
|
|
|
|
|
|
listed
|
|
|
|
|
|
in the
|
|
|
|
|
|
blacklist file
|
|
|
|
|
|
will be
|
|
|
|
|
|
disposed of
|
|
|
|
|
|
according
|
|
|
|
|
|
to
|
|
|
|
|
|
the value assigned
|
|
|
|
|
|
to
|
|
|
|
|
|
the <a href="#Conf">BLACKLIST_DISPOSITION</a>
|
|
|
|
|
|
and <a href="#Conf">BLACKLIST_LOGLEVEL </a>variables in
|
|
|
|
|
|
/etc/shorewall/shorewall.conf.
|
|
|
|
|
|
Only
|
|
|
|
|
|
packets arriving
|
|
|
|
|
|
on interfaces
|
|
|
|
|
|
that
|
|
|
|
|
|
have the
|
|
|
|
|
|
'<a href="#Interfaces">blacklist</a>'
|
|
|
|
|
|
option in
|
|
|
|
|
|
/etc/shorewall/interfaces
|
|
|
|
|
|
are
|
|
|
|
|
|
checked against the
|
|
|
|
|
|
blacklist. The black list is designed to prevent listed
|
|
|
|
|
|
hosts/subnets from accessing services on <u><b>your</b></u> network.<br>
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>Beginning with Shorewall 1.3.8, the blacklist file has three columns:<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>ADDRESS/SUBNET - </b>As described
|
2003-03-22 01:25:40 +01:00
|
|
|
|
above.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>PROTOCOL</b> - Optional. If specified,
|
2003-03-22 01:25:40 +01:00
|
|
|
|
only packets specifying this protocol will be blocked.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>PORTS - </b>Optional; may only be
|
|
|
|
|
|
given if PROTOCOL is tcp, udp or icmp. Expressed as a comma-separated
|
|
|
|
|
|
list of port numbers or service names (from /etc/services). If
|
|
|
|
|
|
present, only packets destined for the specified protocol and
|
|
|
|
|
|
one of the listed ports are blocked. When the PROTOCOL is icmp, the
|
|
|
|
|
|
PORTS column contains a comma-separated list of ICMP type numbers
|
|
|
|
|
|
or names (see "iptables -h icmp").<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Shorewall also has a <a href="blacklisting_support.htm">dynamic blacklist
|
2003-03-22 01:25:40 +01:00
|
|
|
|
capability.</a></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p><font color="#cc6666"><b>IMPORTANT: The Shorewall blacklist file is <u>NOT</u>
|
|
|
|
|
|
designed to police your users' web browsing -- to do that,
|
2003-03-22 01:25:40 +01:00
|
|
|
|
I suggest that you install and configure Squid (<a
|
2002-12-28 16:38:03 +01:00
|
|
|
|
href="http://www.squid-cache.org">http://www.squid-cache.org</a>). </b></font></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<h2><a name="rfc1918"></a>/etc/shorewall/rfc1918 (Added in Version 1.3.1)</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>This file lists the subnets affected by the <a href="#Interfaces"><i>norfc1918</i>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
interface option</a>. Columns in the file are:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>SUBNET</b> - The subnet
|
2003-03-22 01:25:40 +01:00
|
|
|
|
using VLSM notation (e.g., 192.168.0.0/16).</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>TARGET<i> </i></b>- What
|
|
|
|
|
|
to do with packets to/from the SUBNET:
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>RETURN</b> - Process
|
|
|
|
|
|
the packet normally thru the rules and policies.</li>
|
|
|
|
|
|
<li><b>DROP</b> - Silently
|
|
|
|
|
|
drop the packet.</li>
|
|
|
|
|
|
<li><b>logdrop</b> - Log then
|
|
|
|
|
|
drop the packet -- see the <a href="#Conf">RFC1918_LOG_LEVEL</a>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
parameter above.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<h2><a name="Routestopped"></a>/etc/shorewall/routestopped (Added in Version
|
2003-03-22 01:25:40 +01:00
|
|
|
|
1.3.4)</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>This file defines the hosts that are accessible from the firewall when
|
2003-03-22 01:25:40 +01:00
|
|
|
|
the firewall is stopped. Columns in the file are:</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>INTERFACE </b>- The firewall
|
2003-03-22 01:25:40 +01:00
|
|
|
|
interface through which the host(s) comminicate with the firewall.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<li><b>HOST(S) </b>- (Optional)
|
|
|
|
|
|
- A comma-separated list of IP/Subnet addresses. If not supplied
|
2003-03-22 01:25:40 +01:00
|
|
|
|
or supplied as "-" then 0.0.0.0/0 is assumed.</li>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Example: When your firewall is stopped, you want firewall accessibility
|
|
|
|
|
|
from local hosts 192.168.1.0/24 and from your DMZ. Your DMZ
|
2003-03-22 01:25:40 +01:00
|
|
|
|
interfaces through eth1 and your local hosts through eth2.</p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="2" style="border-collapse: collapse;" id="AutoNumber1"
|
|
|
|
|
|
cellpadding="2">
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><u><b>INTERFACE</b></u></td>
|
|
|
|
|
|
<td><u><b>HOST(S)</b></u></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>eth2</td>
|
|
|
|
|
|
<td>192.168.1.0/24</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>eth1</td>
|
|
|
|
|
|
<td>-</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2002-11-09 19:06:34 +01:00
|
|
|
|
<h2><a name="Maclist"></a>/etc/shorewall/maclist (Added in Version 1.3.10)</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
This file is described in the <a
|
2003-01-14 18:18:42 +01:00
|
|
|
|
href="MAC_Validation.html">MAC Validation Documentation</a>.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-02-25 20:24:41 +01:00
|
|
|
|
<h2><a name="ECN"></a>/etc/shorewall/ecn (Added in Version 1.4.0)</h2>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
This file is described in the <a
|
2003-02-25 20:24:41 +01:00
|
|
|
|
href="ECN.html">ECN Control Documentation</a>.<br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
|
|
|
|
|
|
<p><font size="-1"> Updated 4/11/2003 - <a href="support.htm">Tom Eastep</a>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</font></p>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<p><a href="copyright.htm"><font size="2">Copyright</font> <20> <font
|
|
|
|
|
|
size="2">2001, 2002, 2003 Thomas M. Eastep.</font></a><br>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
<br>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<br>
|
|
|
|
|
|
<br>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</body>
|
|
|
|
|
|
</html>
|
