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2002-08-13 22:45:21 +02:00
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<meta name="ProgId" content="FrontPage.Editor.Document">
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<title>Shorewall 1.4 Documentation</title>
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2003-07-04 18:41:22 +02:00
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2003-07-16 20:59:33 +02:00
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2003-07-16 20:59:33 +02:00
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2003-02-20 00:21:55 +01:00
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<meta name="author" content="Tom Eastep">
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</head>
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<body>
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<table border="0" cellpadding="0" cellspacing="0"
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style="border-collapse: collapse;" width="100%" id="AutoNumber4"
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bgcolor="#3366ff" height="90">
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<tbody>
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<tr>
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<td
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width="100%">
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<h1 align="center"><font color="#ffffff">Shorewall 1.4 Reference</font></h1>
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</td>
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</tr>
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</tbody>
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</table>
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<h2 align="center">This documentation is intended primarily for reference.
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Step-by-step instructions for configuring
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Shorewall in common setups may be found in
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the <a href="shorewall_quickstart_guide.htm">QuickStart Guides</a>.</h2>
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<h2>Components</h2>
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<p>Shorewall consists of the following components: </p>
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<ul>
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<li><b><a
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href="#Variables">params</a></b> -- a parameter file installed
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in /etc/shorewall that can be used to establish the
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values of shell variables for use in other files.</li>
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<li><b> <a
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href="#Conf">shorewall.conf</a></b> -- a parameter file
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installed in /etc/shorewall that is used to set several
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firewall parameters.</li>
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<li><b> <a
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href="#Zones">zones</a></b> - a parameter file installed
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in /etc/shorewall that defines a network partitioning
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into "zones"</li>
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<li><b> <a
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href="#Policy">policy</a></b> -- a parameter file installed
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in /etc/shorewall/ that establishes overall firewall
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policy.</li>
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<li><b> <a
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href="#Rules">rules</a> </b> -- a parameter file installed
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in /etc/shorewall and used to express firewall
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rules that are exceptions to the high-level policies
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established in /etc/shorewall/policy.</li>
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<li><b><a
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href="#Blacklist">blacklist</a> -- </b>a parameter file
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installed in /etc/shorewall and used to list blacklisted
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IP/subnet/MAC addresses.</li>
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<li><b><a href="#ECN">ecn</a></b> -- a parameter
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file installed in /etc/shorewall and used to selectively disable
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Explicit Congestion Notification (ECN - RFC 3168).<br>
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</li>
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<li><b> functions</b>
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-- a set of shell functions used by both the firewall
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and shorewall shell programs. Installed in /etc/shorewall
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prior to version 1.3.2, in /var/lib/shorewall in version
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s 1.3.2-1.3.8 and in /usr/lib/shorewall in later versions.</li>
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<li><b> <a
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href="#modules">modules</a></b> -- a parameter file installed
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in /etc/shorewall and that specifies kernel modules and
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their parameters. Shorewall will automatically load
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the modules specified in this file.</li>
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<li><a href="#TOS"><b> tos</b> </a>-- a parameter
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file installed in /etc/shorewall that is used to specify
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how the Type of Service (TOS) field in packets is to be set.<br>
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</li>
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<li><b><a
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href="#Scripts">common.def</a></b> -- a parameter file
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installed in in /etc/shorewall that defines firewall-wide
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rules that are applied before a DROP or REJECT policy
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is applied.</li>
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<li><b> <a
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href="#Interfaces">interfaces</a> </b> -- a parameter
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file installed in /etc/shorewall/ and used to describe the
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interfaces on the firewall system.</li>
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<li><a
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href="#Hosts"><b> hosts</b> </a>-- a parameter file
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installed in /etc/shorewall/ and used to describe
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individual hosts or subnetworks in zones.</li>
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<li><b><a
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href="#Maclist">maclist</a> </b>-- a parameter file
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installed in /etc/shorewall and used to verify the MAC address
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(and possibly also the IP address(es)) of devices.<br>
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</li>
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<li><b> <a
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href="#Masq">masq</a></b> - This file also describes
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IP masquerading under Shorewall and is installed in
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/etc/shorewall.</li>
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<li><b><a
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href="shorewall_firewall_structure.htm">firewall</a></b> -- a shell
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program that reads the configuration files in
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/etc/shorewall and configures your firewall.
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This file is installed in your init.d directory
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(/etc/rc.d/init.d ) where it is renamed <i>shorewall.</i>
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/etc/shorewall/firewall (/var/lib/shorewall/firewall
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in versions 1.3.2-1.3.8 and /usr/lib/shorewall/firewall
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in 1.3.9 and later) is a symbolic link to this program.</li>
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<li><b> <a
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href="#NAT">nat</a></b> -- a parameter file in /etc/shorewall
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used to define <a href="#NAT"> static NAT</a> .</li>
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<li><b> <a
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href="#ProxyArp">proxyarp</a></b> -- a parameter file in
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/etc/shorewall used to define <a href="#ProxyArp"> Proxy
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Arp</a> .</li>
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<li><b><a
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href="#rfc1918">rfc1918</a></b> -- a parameter file in
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/etc/shorewall used to define the treatment of packets under
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the <a href="#Interfaces">norfc1918 interface option</a>.</li>
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<li><b><a
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href="#Routestopped">routestopped</a></b> -- a parameter
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file in /etc/shorewall used to define those hosts that can
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access the firewall when Shorewall is stopped.</li>
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<li><a
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href="traffic_shaping.htm#tcrules"><b>tcrules</b> </a>-- a parameter
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file in /etc/shorewall used to define rules for classifying
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packets for <a href="traffic_shaping.htm">Traffic Shaping/Control</a>.</li>
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<li><b> <a
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href="#Tunnels">tunnels</a></b> -- a parameter file in
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/etc/shorewall used to define IPSec tunnels.</li>
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<li><b> <a
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href="#Starting">shorewall</a> </b> -- a shell program
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(requiring a Bourne shell or derivative) used
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to control and monitor the firewall. This should be placed
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in /sbin or in /usr/sbin (the install.sh script and
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the rpm install this file in /sbin).</li>
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<li><b> version</b>
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-- a file created in /etc/shorewall/
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(/var/lib/shorewall in version 1.3.2-1.3.8 and /usr/lib/shorewall
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beginning in version 1.3.9) that describes the version
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of Shorewall installed on your system.</li>
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</ul>
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<h2><a name="Variables"></a> /etc/shorewall/params</h2>
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<p>You may use the file /etc/shorewall/params file to set shell variables
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that you can then use in some of the other
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configuration files.</p>
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<p>It is suggested that variable names begin with an upper case letter<font
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size="1"> </font>to distinguish them from variables used internally
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within the Shorewall programs</p>
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<p>Example:</p>
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2003-01-22 01:37:23 +01:00
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<pre><font face="Courier"> NET_IF=eth0<br> NET_BCAST=130.252.100.255<br> NET_OPTIONS=blacklist,norfc1918</font></pre>
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<p>Example (/etc/shorewall/interfaces record):</p>
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<pre> <font face="Courier">net $NET_IF $NET_BCAST $NET_OPTIONS</font></pre>
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<p>The result will be the same as if the record had been written</p>
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2003-01-22 01:37:23 +01:00
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<pre> <font face="Courier">net eth0 130.252.100.255 blacklist,norfc1918</font></pre>
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<p>Variables may be used anywhere in the other configuration
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files.</p>
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<h2><b><a name="Zones"></a> </b>/etc/shorewall/zones</h2>
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<p>This file is used to define the network zones. There is one entry
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in /etc/shorewall/zones for each zone; Columns
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in an entry are:</p>
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<ul>
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<li><b> ZONE</b>
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- short name for the zone. The name should be 5 characters
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or less in length (4 characters or less if you are running Shorewall
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1.4.4 or later) and consist of lower-case letters or numbers.
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Short names must begin with a letter and the name assigned
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to the firewall is reserved for use by Shorewall itself.
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Note that the output produced by iptables is much easier
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to read if you select short names that are three characters
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or less in length. The name "all" may not be used as
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a zone name nor may the zone name assigned to the firewall itself
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via the FW variable in <a href="#Conf">/etc/shorewall/shorewall.conf</a>.</li>
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<li><b> DISPLAY</b>
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- The name of the zone as displayed during Shorewall
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startup.</li>
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<li><b> COMMENTS</b>
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- Any comments that you want to make about the zone.
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Shorewall ignores these comments.</li>
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</ul>
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<p>The /etc/shorewall/zones file released with Shorewall is as follows:</p>
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<table border="1" style="border-collapse: collapse;" cellpadding="2">
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<tbody>
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<tr>
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<td><b>
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ZONE</b></td>
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<td><b>
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DISPLAY</b></td>
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<td><b>
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COMMENTS</b></td>
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</tr>
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<tr>
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<td>net</td>
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<td>Net</td>
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<td>Internet</td>
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</tr>
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<tr>
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<td>loc</td>
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<td>Local</td>
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<td>Local
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2003-07-07 16:18:52 +02:00
|
|
|
|
networks</td>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>dmz</td>
|
|
|
|
|
|
<td>DMZ</td>
|
|
|
|
|
|
<td>Demilitarized
|
2003-07-07 16:18:52 +02:00
|
|
|
|
zone</td>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</tr>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<p>You may add, delete and modify entries in the /etc/shorewall/zones file
|
|
|
|
|
|
as desired so long as you have at least one
|
|
|
|
|
|
zone defined.</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p><b><font size="5" color="#ff0000"> Warning 1: </font><font
|
2003-07-16 20:59:33 +02:00
|
|
|
|
color="#ff0000"> If you rename or delete a zone, you should perform "shorewall
|
|
|
|
|
|
stop; shorewall start" to install the change
|
|
|
|
|
|
rather than "shorewall restart".</font></b></p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p><b><font size="5" color="#ff0000">Warning 2: </font><font
|
2003-07-16 20:59:33 +02:00
|
|
|
|
color="#ff0000">The order of entries in the /etc/shorewall/zones file is
|
|
|
|
|
|
significant <a href="#Nested">in some cases</a>.</font></b></p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<h2><font color="#660066"><a name="Interfaces"></a> </font>/etc/shorewall/interfaces</h2>
|
2003-07-16 20:59:33 +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. Columns in an entry are:</p>
|
|
|
|
|
|
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +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 can be listed on only one record
|
|
|
|
|
|
in this file. <font color="#ff0000"><b>D</b><b>O NOT INCLUDE
|
|
|
|
|
|
THE LOOPBACK INTERFACE (lo) IN THIS FILE!!!</b></font></li>
|
|
|
|
|
|
<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>
|
2003-05-28 21:20:23 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>the interface must be up before you start
|
|
|
|
|
|
your firewall</li>
|
|
|
|
|
|
<li>the interface
|
|
|
|
|
|
must only be attached to a single sub-network (i.e.,
|
2003-07-07 16:18:52 +02:00
|
|
|
|
there must have a single broadcast address). </li>
|
2003-06-18 22:03:19 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b> OPTIONS</b>
|
|
|
|
|
|
- a comma-separated list of options. Possible options
|
2003-07-07 16:18:52 +02:00
|
|
|
|
include:<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
<b>newnotsyn </b>(Added in version 1.4.6) - This
|
|
|
|
|
|
option overrides <a href="#Conf">NEWNOTSYN=No</a> for packets arriving
|
|
|
|
|
|
on this interface. In other words, packets coming in on this interface
|
|
|
|
|
|
are processed as if NEWNOTSYN=Yes had been specified in <a
|
|
|
|
|
|
href="#Conf">/etc/shorewall/shorewall.conf</a>.<br>
|
|
|
|
|
|
<b><br>
|
|
|
|
|
|
routeback </b>(Added in version 1.4.2) - This option causes Shorewall
|
|
|
|
|
|
to set up handling for routing packets that arrive on this interface
|
|
|
|
|
|
back out the same interface. If this option is specified, the ZONE
|
|
|
|
|
|
column may not contain "-".<br>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<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 on this interface
|
|
|
|
|
|
to be checked against the <a href="#Blacklist">blacklist</a>.<b><br>
|
|
|
|
|
|
<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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
you select the <b>norfc1918 </b>option (see below).</p>
|
|
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<p> <b>norfc1918</b> - Packets arriving on this interface and that
|
|
|
|
|
|
have a source address that is reserved in RFC 1918 or in other
|
|
|
|
|
|
RFCs will be dropped after being optionally logged.
|
|
|
|
|
|
If <a 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 also be logged and dropped.<br>
|
|
|
|
|
|
<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 the IANA or
|
|
|
|
|
|
by other RFCs.</p>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<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 access to certain addresses
|
|
|
|
|
|
from the above list, see <a href="FAQ.htm#faq14">FAQ 14.</a></p>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
patch from 2.4.17-rc1 is <a
|
2003-07-16 20:59:33 +02:00
|
|
|
|
href="ftp://ftp.shorewall.net/pub/shorewall/misc/unclean.patch">available
|
|
|
|
|
|
for download</a>. I am currently
|
|
|
|
|
|
running this patch applied to
|
|
|
|
|
|
kernel 2.4.16.</p>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<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>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<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>. May only be
|
|
|
|
|
|
specified for ethernet interfaces.</p>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<p>My recommendations concerning options:<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>External Interface --
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<b>tcpflags,blacklist,norfc1918,routefilter</b></li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>Wireless Interface --
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<b>maclist,routefilter,tcpflags</b><br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li>Don't use <b>dropunclean</b>
|
|
|
|
|
|
-- It's broken in my opinion</li>
|
|
|
|
|
|
<li>Use <b>logunclean</b>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
only when you are trying to debug a problem</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>Use <b>dhcp </b>and <b>proxyarp</b>
|
|
|
|
|
|
when needed.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<p> </p>
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>Example 2: You have a standalone dialup GNU/Linux System. Your /etc/shorewall/interfaces
|
|
|
|
|
|
file would be:</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>Example 3: You have local interface eth1 with two IP addresses -
|
2003-07-07 16:18:52 +02:00
|
|
|
|
192.168.1.1/24 and 192.168.12.1/24</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-06-18 22:03:19 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><font color="#660066"><a name="Hosts"></a> </font>/etc/shorewall/hosts
|
|
|
|
|
|
Configuration</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<ol>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>You have more than one zone connecting through
|
2003-07-07 16:18:52 +02:00
|
|
|
|
a single interface; or</b></li>
|
2003-07-16 20:59:33 +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 those subnetworks.</b><br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</ol>
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b> ZONE
|
|
|
|
|
|
</b> - A zone defined in the <a href="#Zones">/etc/shorewall/zones</a>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
file.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b> HOST(S)</b>
|
|
|
|
|
|
- The name of a network interface followed by a colon
|
2003-07-07 16:18:52 +02:00
|
|
|
|
(":") followed by a comma-separated list either:</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ol>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>An IP address (example - eth1:192.168.1.3)</li>
|
|
|
|
|
|
|
|
|
|
|
|
<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>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<p>The interface name much match an entry in /etc/shorewall/interfaces.<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p><font color="#ff0000"><b>Warning: </b></font><b>If you are running a
|
|
|
|
|
|
version of Shorewall earlier than 1.4.6, only a single host/subnet address
|
2003-07-07 16:18:52 +02:00
|
|
|
|
may be specified in an entry in /etc/shorewall/hosts.</b><br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b> OPTIONS</b>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
- A comma-separated list of option</li>
|
|
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b>routeback </b>(Added in version 1.4.2) - This option causes Shorewall
|
|
|
|
|
|
to set up handling for routing packets sent by this host group back
|
|
|
|
|
|
back to the same group.<b><br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
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 adding additional rules.</p>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p>Example 1:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Your local interface is eth1 and you have two groups of local hosts that
|
|
|
|
|
|
you want to make into separate zones:</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>192.168.1.0/25
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li>192.168.1.128/</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p>Your /etc/shorewall/interfaces file might look like:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> The '-' in the ZONE column for eth1 tells Shorewall that eth1 interfaces
|
|
|
|
|
|
to multiple zones.</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Your /etc/shorewall/hosts file might look like:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<blockquote> <font
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p>Example 2:</p>
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>192.168.1.0/25 </li>
|
|
|
|
|
|
<li>192.168.1.128/25</li>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p> Your /etc/shorewall/interfaces file might look like:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>
|
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|
|
ZONE</b></td>
|
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|
<td><b>
|
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|
|
INTERFACE</b></td>
|
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<td><b>
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|
BROADCAST</b></td>
|
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<td><b>
|
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|
|
OPTIONS</b></td>
|
|
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|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
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|
|
<td>net</td>
|
|
|
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|
|
<td>eth0</td>
|
|
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|
|
<td>detect</td>
|
|
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|
|
<td>dhcp,norfc1918</td>
|
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</tr>
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<tr>
|
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|
<td>loc<br>
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|
</td>
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|
|
<td>eth1</td>
|
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|
|
<td>192.168.1.127,192.168.1.255<br>
|
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|
</td>
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|
|
<td> <br>
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|
</td>
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|
|
</tr>
|
2003-07-07 16:18:52 +02:00
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|
2003-07-16 20:59:33 +02:00
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|
|
</tbody>
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|
2003-02-20 00:21:55 +01:00
|
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|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
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|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p> Your /etc/shorewall/hosts file might look like:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<blockquote> <font
|
2003-07-16 20:59:33 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica">
|
|
|
|
|
|
</font>
|
|
|
|
|
|
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>
|
|
|
|
|
|
ZONE</b></td>
|
|
|
|
|
|
<td><b>
|
|
|
|
|
|
HOST(S)</b></td>
|
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|
|
|
|
<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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2003-07-07 16:18:52 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
If you are running Shorewall
|
2003-07-07 16:18:52 +02:00
|
|
|
|
1.4.6 or later, your hosts file may look like:<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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>eth1:192.168.1.0/25,192.168.1.128/25</td>
|
|
|
|
|
|
<td> <br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
|
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
</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 <a href="#CONTINUE">CONTINUE policy</a> described
|
|
|
|
|
|
below.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><font color="#660066"><a name="Policy"></a> </font>/etc/shorewall/policy
|
2003-07-07 16:18:52 +02:00
|
|
|
|
Configuration.</h2>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<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 to establish connections with other
|
|
|
|
|
|
zones.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<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 is applied.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p>Four policies are defined:</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b> ACCEPT</b>
|
|
|
|
|
|
- The connection is allowed.</li>
|
|
|
|
|
|
<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 packet being
|
|
|
|
|
|
returned to the client.</li>
|
|
|
|
|
|
<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, see below.</li>
|
|
|
|
|
|
<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 </b>columns
|
|
|
|
|
|
must be left blank.<br>
|
|
|
|
|
|
</li>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
|
|
<p> For each policy specified in /etc/shorewall/policy, you can indicate
|
|
|
|
|
|
that you want a message sent to your system
|
|
|
|
|
|
log each time that the policy is applied.</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Entries in /etc/shorewall/policy have four columns as follows:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ol>
|
2003-06-18 22:03:19 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +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 <a href="#Conf">name of the firewall
|
|
|
|
|
|
zone</a> or "all").</li>
|
|
|
|
|
|
|
|
|
|
|
|
<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 href="shorewall_logging.html">syslog
|
2003-07-07 16:18:52 +02:00
|
|
|
|
level</a>.</li>
|
|
|
|
|
|
|
2003-07-16 20:59:33 +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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
requests in excess of these limits will be dropped.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ol>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<p> In the SOURCE and DEST columns, you can enter "all" to indicate all
|
|
|
|
|
|
zones. </p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> The policy file installed by default is as follows:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<blockquote> <font
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<td> <br>
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2003-02-04 16:26:02 +01:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> This table may be interpreted as follows:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>All connection
|
|
|
|
|
|
requests from the local network to hosts on the
|
|
|
|
|
|
internet are accepted.</li>
|
|
|
|
|
|
<li>All connection
|
|
|
|
|
|
requests originating from the internet are ignored
|
|
|
|
|
|
and logged at level KERNEL.INFO.</li>
|
|
|
|
|
|
<li>All other connection
|
|
|
|
|
|
requests are rejected and logged.</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<p><b><font size="4" color="#ff0000">WARNING:</font></b></p>
|
2003-07-16 20:59:33 +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 third entry in the file specifies
|
|
|
|
|
|
REJECT.</b></font></p>
|
|
|
|
|
|
|
2003-01-22 01:37:23 +01:00
|
|
|
|
<blockquote> <font
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>
|
|
|
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|
|
<td>all</td>
|
|
|
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|
|
<td>ACCEPT</td>
|
|
|
|
|
|
<td> <br>
|
|
|
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|
|
</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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<h4><a name="IntraZone"></a>IntraZone Traffic</h4>
|
2003-07-16 20:59:33 +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. Cases where you might not want that behavior are:<br>
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
2003-03-22 01:25:40 +01:00
|
|
|
|
<ol>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>Multiple 'net' interfaces to different ISPs.
|
|
|
|
|
|
You don't want to route traffic from one ISP to the other through
|
|
|
|
|
|
your firewall.</li>
|
|
|
|
|
|
<li>Multiple VPN clients. You don't necessarily want
|
|
|
|
|
|
them to all be able to communicate between themselves using your
|
|
|
|
|
|
gateway/router.<br>
|
|
|
|
|
|
</li>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ol>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +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 at an example:</p>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> /etc/shorewall/zones:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
system at home</td>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>Internet</td>
|
|
|
|
|
|
<td>The
|
|
|
|
|
|
Internet</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>loc</td>
|
|
|
|
|
|
<td>Loc</td>
|
|
|
|
|
|
<td>Local
|
2003-07-07 16:18:52 +02:00
|
|
|
|
Network</td>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</tr>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> /etc/shorewall/interfaces:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
|
|
|
|
|
<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>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> /etc/shorewall/hosts:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<blockquote> <font
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +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 that <b>sam</b> must be listed before
|
|
|
|
|
|
<b>net</b> in /etc/shorewall/zones.</p>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<p> /etc/shorewall/policy:</p>
|
2003-07-16 20:59:33 +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
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<blockquote> <font
|
|
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font><font
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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 is constructed, this requires
|
|
|
|
|
|
two rules as follows:</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<p> </p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<font
|
2003-07-04 18:41:22 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font><font
|
2003-07-16 20:59:33 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
|
|
|
|
|
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-11-09 19:06:34 +01:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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>
|
|
|
|
|
|
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<h2><font color="#660066"><a name="Rules"></a> </font>/etc/shorewall/rules</h2>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<p>The /etc/shorewall/rules file defines exceptions to the policies established
|
|
|
|
|
|
in the /etc/shorewall/policy file. There is one
|
|
|
|
|
|
entry in /etc/shorewall/rules for each of these rules.
|
|
|
|
|
|
<br>
|
|
|
|
|
|
</p>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<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 a warning and will be ignored.<br>
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
2003-02-20 00:21:55 +01:00
|
|
|
|
<p>Entries in the file have the following columns:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>ACTION</b>
|
|
|
|
|
|
|
|
|
|
|
|
|
2003-07-04 18:41:22 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>ACCEPT, DROP,
|
|
|
|
|
|
REJECT, CONTINUE. These have the same meaning here as
|
2003-07-07 16:18:52 +02:00
|
|
|
|
in the policy file above.</li>
|
2003-07-16 20:59:33 +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 <u>N</u>etwork
|
|
|
|
|
|
<u>A</u>ddress <u>T</u>ranslation"</li>
|
|
|
|
|
|
<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. DNAT- works like DNAT but only
|
2003-07-07 16:18:52 +02:00
|
|
|
|
generates the header-rewriting rule.<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li>REDIRECT
|
|
|
|
|
|
-- Causes the connection request to be redirected to
|
|
|
|
|
|
a port on the local (firewall) system.</li>
|
|
|
|
|
|
<li>REDIRECT- -- The above ACTION (REDIRECT) generates
|
|
|
|
|
|
two iptables rules: 1) and header-rewriting rule in the Netfilter
|
|
|
|
|
|
'nat' table and; 2) an ACCEPT rule in the Netfilter 'filter'
|
|
|
|
|
|
table. REDIRECT- works like REDIRECT but only generates the header-rewriting
|
|
|
|
|
|
rule.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li>LOG - Log the packet -- requires a syslog
|
|
|
|
|
|
level (see below).</li>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-06-18 22:03:19 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<p>The ACTION may optionally be followed by ":" and a <a
|
2003-07-16 20:59:33 +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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
or REDIRECT requires that you have <a
|
|
|
|
|
|
href="#NatEnabled">NAT enabled</a>.<br>
|
2003-07-16 20:59:33 +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.
|
2003-07-07 16:18:52 +02:00
|
|
|
|
There is an <a href="#Exclude">example</a> above.<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<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:
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +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 not be a DNS name.</li>
|
|
|
|
|
|
<li>A MAC Address
|
|
|
|
|
|
in <a href="configuration_file_basics.htm#MAC">Shorewall format</a>.</li>
|
|
|
|
|
|
<li>A subnet
|
|
|
|
|
|
- refers to a connection request from any host in the
|
|
|
|
|
|
specified subnet (example net:155.186.235.0/24).</li>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +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:
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +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).
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
Restrictions:<br>
|
2003-06-18 22:03:19 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>MAC addresses may not be specified.</li>
|
|
|
|
|
|
<li>In DNAT rules, only IP addresses may be
|
2003-07-07 16:18:52 +02:00
|
|
|
|
given -- DNS names are not permitted.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>You may not specify both an IP address
|
|
|
|
|
|
and an interface name in the DEST column.</li>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
Unlike in the SOURCE column, a range of IP addresses may be specified
|
|
|
|
|
|
in the DEST column as <i><first address>-<last address>.
|
|
|
|
|
|
</i>When the ACTION is DNAT or DNAT-, connections will be assigned to
|
|
|
|
|
|
the addresses in the range in a round-robin fashion (load-balancing).<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b> PROTO</b>
|
|
|
|
|
|
- Protocol. Must be a protocol name from /etc/protocols,
|
|
|
|
|
|
a number or "all". Specifies the protocol of the connection
|
2003-07-07 16:18:52 +02:00
|
|
|
|
request.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<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 may only be non-empty if the
|
|
|
|
|
|
ACTION is DNAT or REDIRECT.<br>
|
|
|
|
|
|
<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 particular IP addresses
|
|
|
|
|
|
(see Example 2 below for another usage). Those IP addresses are specified
|
|
|
|
|
|
in the ORIGINAL DEST column as a comma-separated list.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
The IP address(es)
|
|
|
|
|
|
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 server (This
|
|
|
|
|
|
is called "Source NAT" or SNAT.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
If this list begins with "!" then the rule will only apply if the
|
2003-07-07 16:18:52 +02:00
|
|
|
|
original destination address matches none of the addresses listed.<br>
|
2003-07-16 20:59:33 +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 the scope
|
|
|
|
|
|
of a rule by incoming interface. <br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
</b>Example:
|
|
|
|
|
|
DNAT loc<u>:192.168.1.0/24</u> loc:192.168.1.3
|
|
|
|
|
|
tcp www - 206.124.146.179:192.168.1.3<b><br>
|
|
|
|
|
|
<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,
|
2003-07-07 16:18:52 +02:00
|
|
|
|
simply use a colon followed by the SNAT address.</li>
|
|
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p><b> <font face="Century Gothic, Arial, Helvetica"> <a
|
2003-07-16 20:59:33 +02:00
|
|
|
|
name="PortForward"></a> </font>Example 1. </b> You wish to forward all
|
|
|
|
|
|
ssh connection requests from the internet to
|
|
|
|
|
|
local system 192.168.1.3. </p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<blockquote> <font
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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>
|
|
|
|
|
|
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<blockquote> <font
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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>
|
|
|
|
|
|
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<blockquote> <font
|
2002-09-16 19:13:10 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font><font
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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
|
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|
|
|
|
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
|
|
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|
|
|
sent to 192.168.2.2 <u> regardless of
|
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|
|
the site that the user
|
|
|
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|
|
was trying to connect
|
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|
|
to</u>. That is clearly
|
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|
|
not what you want <img
|
2003-07-04 18:41:22 +02:00
|
|
|
|
border="0" src="images/SY00079.gif" width="20" height="20" align="top">
|
2003-07-16 20:59:33 +02:00
|
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|
.</p>
|
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|
2003-04-13 17:28:32 +02:00
|
|
|
|
<blockquote> <font
|
|
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font><font
|
2003-07-16 20:59:33 +02:00
|
|
|
|
face="Century Gothic, Arial, Helvetica"> </font>
|
|
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|
|
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|
2003-04-13 17:28:32 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td><b>ACTION</b></td>
|
|
|
|
|
|
<td><b>SOURCE</b></td>
|
|
|
|
|
|
<td><b>DEST</b></td>
|
|
|
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|
<td><b>
|
|
|
|
|
|
PROTO</b></td>
|
|
|
|
|
|
<td><b>DEST<br>
|
|
|
|
|
|
PORT(S)</b></td>
|
|
|
|
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|
<td><b>SOURCE<br>
|
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|
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|
PORT(S)</b></td>
|
|
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|
|
<td><b>ORIGINAL<br>
|
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|
|
DEST</b></td>
|
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|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td>DNAT</td>
|
|
|
|
|
|
<td>net</td>
|
|
|
|
|
|
<td>dmz:192.168.2.2</td>
|
|
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|
|
<td>tcp</td>
|
|
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|
|
|
<td>ftp</td>
|
|
|
|
|
|
<td> <br>
|
|
|
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|
|
</td>
|
|
|
|
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|
<td> <br>
|
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|
|
|
|
</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>
|
|
|
|
|
|
|
2003-04-13 17:28:32 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</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 entry is appropriate:</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<p> passive ports 0.0.0.0/0 65500 65534</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>If you are running pure-ftpd, you would include "-p 65500:65534" on
|
|
|
|
|
|
the pure-ftpd runline.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p>The important point here is to ensure that the port range used for FTP
|
|
|
|
|
|
passive connections is unique and will not overlap
|
|
|
|
|
|
with any usage on the firewall system.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<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
|
2003-07-16 20:59:33 +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;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
2003-04-13 17:28:32 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<b>Example 6.</b> You wish to allow access
|
|
|
|
|
|
to the SMTP server in your DMZ from all zones.<br>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2003-06-18 22:03:19 +02:00
|
|
|
|
<table cellpadding="2" cellspacing="0" border="1">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2003-06-18 22:03:19 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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. </b>Your firewall's
|
|
|
|
|
|
external interface has several IP addresses but you only want to accept
|
2003-07-07 16:18:52 +02:00
|
|
|
|
SSH connections on address 206.124.146.176.<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2003-06-18 22:03:19 +02:00
|
|
|
|
<table cellpadding="2" cellspacing="0" border="1">
|
2003-07-16 20:59:33 +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">net<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">fw:206.124.146.176<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">tcp<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">22<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2003-01-14 18:18:42 +01:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
<b>Example 8 (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 to tcp port 25 on 192.0.2.177. <br>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2003-07-04 18:41:22 +02:00
|
|
|
|
<table cellpadding="2" cellspacing="0" border="1">
|
2003-07-16 20:59:33 +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>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2003-07-04 18:41:22 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
Using "DNAT-" rather than "DNAT"
|
|
|
|
|
|
avoids two extra copies of the third rule from being generated.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
<b>Example 9 (Shorewall version 1.4.6 or later). </b>You have 9 http
|
|
|
|
|
|
servers behind a Shorewall firewall and you want connection requests to
|
|
|
|
|
|
be distributed among your servers. The servers are 192.168.1.101-192.168.1.109.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2003-07-04 18:41:22 +02:00
|
|
|
|
<table cellpadding="2" cellspacing="0" border="1">
|
2003-07-16 20:59:33 +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">loc:192.168.1.101-192.168.1.109<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">tcp<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top">80<br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td valign="top"><br>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
</tr>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-07-07 16:18:52 +02:00
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<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. In order to make use of this
|
|
|
|
|
|
feature, you must have <a href="#NatEnabled">NAT enabled</a>
|
|
|
|
|
|
.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p> Columns are:</p>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<ul>
|
|
|
|
|
|
<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 through the named interface.</font></b><br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
The subnet may
|
|
|
|
|
|
be optionally followed by "!' and a comma-separated
|
|
|
|
|
|
list of addresses and/or subnets that are to be
|
|
|
|
|
|
excluded from masquerading.</li>
|
|
|
|
|
|
<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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
|
|
<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 /etc/shorewall/masq file would look like:
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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 subnet to the remote subnet 10.1.0.0/16
|
|
|
|
|
|
only.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-07-07 16:18:52 +02:00
|
|
|
|
</tbody>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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>
|
|
|
|
|
|
|
2003-03-07 00:41:31 +01:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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>
|
|
|
|
|
|
|
2003-01-31 22:50:51 +01:00
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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>
|
|
|
|
|
|
|
2003-01-31 22:50:51 +01:00
|
|
|
|
</table>
|
2003-07-16 20:59:33 +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>
|
|
|
|
|
|
|
|
|
|
|
|
<table border="1" cellpadding="2" style="border-collapse: collapse;">
|
|
|
|
|
|
<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>
|
|
|
|
|
|
|
|
|
|
|
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|
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|
|
|
</tbody>
|
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|
|
|
|
|
|
|
</table>
|
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|
</blockquote>
|
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|
|
<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)
|
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|
|
|
|
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
|
2003-07-16 20:59:33 +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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
are:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b> ADDRESS</b>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
- address of the system.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b> INTERFACE</b>
|
|
|
|
|
|
- the interface that connects to the system. If the
|
|
|
|
|
|
interface is obvious from the subnetting, you may
|
|
|
|
|
|
enter "-" in this column.</li>
|
|
|
|
|
|
<li><b> EXTERNAL</b>
|
|
|
|
|
|
- the external interface that you want to honor
|
|
|
|
|
|
ARP requests for the ADDRESS specified in the first
|
|
|
|
|
|
column.</li>
|
|
|
|
|
|
<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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +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 flush the ARP cache on host A as well.</b></font></p>
|
|
|
|
|
|
|
|
|
|
|
|
<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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
configure your firewall as follows:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-05-18 20:27:36 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>eth0 - 155.186.235.1
|
|
|
|
|
|
(internet connection)</li>
|
|
|
|
|
|
<li>eth1 - 192.168.9.0/24
|
2003-07-07 16:18:52 +02:00
|
|
|
|
(masqueraded local systems)</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>eth2 - 192.168.10.1
|
2003-07-07 16:18:52 +02:00
|
|
|
|
(interface to your DMZ)</li>
|
|
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
|
|
<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;">
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +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. See the Proxy ARP Subnet Mini HOWTO (<a
|
|
|
|
|
|
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 in the Kernel or in FreeS/Wan.
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p>You <b>might</b> be able to work around this problem using the following
|
|
|
|
|
|
(I haven't tried it):</p>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>In /etc/shorewall/init, include:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<p> qt service ipsec stop</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>In /etc/shorewall/start, include:</p>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<p> qt service ipsec start</p>
|
|
|
|
|
|
|
|
|
|
|
|
<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
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b> EXTERNAL</b>
|
|
|
|
|
|
- External IP address - <u>This should NOT be
|
|
|
|
|
|
the primary IP address of the interface named in the next
|
|
|
|
|
|
column.</u></li>
|
|
|
|
|
|
<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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
YOUR SHOREWALL CONFIGURATION.</b><EFBFBD></li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b> INTERNAL
|
|
|
|
|
|
</b> - Internal IP address.</li>
|
|
|
|
|
|
<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>
|
|
|
|
|
|
in your kernel.</li>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
|
|
<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>, PPTP
|
|
|
|
|
|
and 6to4.tunnels with end-points on your firewall. To use ipsec,
|
|
|
|
|
|
you must install version 1.9, 1.91 or the current <a
|
|
|
|
|
|
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 results in kernel compilation errors.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p><b><a href="IPSEC.htm"> Instructions for setting up IPSEC tunnels may
|
|
|
|
|
|
be found here,</a></b> <b><a
|
|
|
|
|
|
href="IPIP.htm">instructions for IPIP and GRE tunnels
|
|
|
|
|
|
are here</a></b>, <b><a href="OPENVPN.html">instructions for OpenVPN tunnels
|
|
|
|
|
|
are here</a></b>, <b><a href="PPTP.htm">instructions for PPTP
|
|
|
|
|
|
tunnels are here</a> and <a href="6to4.htm">instructions for 6to4
|
|
|
|
|
|
tunnels</a> are here.</b></p>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2002-12-28 16:38:03 +01:00
|
|
|
|
<h2><a name="Conf"></a>/etc/shorewall/shorewall.conf</h2>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> This file is used to set the following firewall parameters:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>SHOREWALL_SHELL
|
|
|
|
|
|
</b>- Added at version 1.4.6<br>
|
|
|
|
|
|
This parameter is used to specify the shell program to be used to interpret
|
|
|
|
|
|
the firewall script (/usr/share/shorewall/firewall). If not specified or
|
|
|
|
|
|
specified as a null value, /bin/sh is assumed.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>LOGFORMAT - </b>Added at version 1.4.4.<br>
|
|
|
|
|
|
The value of this variable generate the --log-prefix setting
|
|
|
|
|
|
for Shorewall logging rules. It contains a 'printf' formatting template
|
|
|
|
|
|
which accepts three arguments (the chain name, logging rule number (optional)
|
2003-07-07 16:18:52 +02:00
|
|
|
|
and the disposition). To use LOGFORMAT with fireparse (<a
|
2003-07-16 20:59:33 +02:00
|
|
|
|
href="http://www.fireparse.com">http://www.fireparse.com</a>), set it as:<br>
|
|
|
|
|
|
<20><br>
|
|
|
|
|
|
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> LOGFORMAT="fp=%s:%d a=%s "<br>
|
|
|
|
|
|
<20><br>
|
|
|
|
|
|
If the LOGFORMAT value contains the substring '%d' then the
|
|
|
|
|
|
logging rule number is calculated and formatted in that position; if
|
|
|
|
|
|
that substring is not included then the rule number is not included.
|
|
|
|
|
|
If not supplied or supplied as empty (LOGFORMAT="") then "Shorewall:%s:%s:"
|
|
|
|
|
|
is assumed.<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
<b>CAUTION: </b>/sbin/shorewall uses the leading part
|
|
|
|
|
|
of the LOGFORMAT string (up to but not including the first '%') to
|
|
|
|
|
|
find log messages in the 'show log', 'status' and 'hits' commands. This
|
|
|
|
|
|
part should not be omitted (the LOGFORMAT should not begin with "%")
|
|
|
|
|
|
and the leading part should be sufficiently unique for /sbin/shorewall
|
2003-07-07 16:18:52 +02:00
|
|
|
|
to identify Shorewall messages.<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>CLEAR_TC</b> - Added at version 1.3.13<br>
|
|
|
|
|
|
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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
at version 1.3.12<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
If your kernel has a FORWARD chain
|
|
|
|
|
|
in the mangle table, you may set MARK_IN_FORWARD_CHAIN=Yes
|
2003-07-07 16:18:52 +02:00
|
|
|
|
to cause the marking specified in the <a
|
2003-07-16 20:59:33 +02:00
|
|
|
|
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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
at version 1.3.12<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
This parameter determines the
|
2003-07-07 16:18:52 +02:00
|
|
|
|
level at which packets logged under the <a
|
2003-07-16 20:59:33 +02:00
|
|
|
|
href="Documentation.htm#rfc1918">'norfc1918' mechanism </a>
|
|
|
|
|
|
are logged. The value must be a valid <a
|
|
|
|
|
|
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 are always logged at the info level.</li>
|
|
|
|
|
|
<li><b>TCP_FLAGS_DISPOSITION
|
2003-07-07 16:18:52 +02:00
|
|
|
|
- </b>Added in Version 1.3.11<br>
|
2003-07-16 20:59:33 +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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
- </b>Added in Version 1.3.11<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
Determines the <a
|
|
|
|
|
|
href="shorewall_logging.html">syslog level</a> for logging packets
|
2003-07-07 16:18:52 +02:00
|
|
|
|
that fail the checks enabled by the <a
|
2003-07-16 20:59:33 +02:00
|
|
|
|
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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
</b>- Added in Version 1.3.10<br>
|
2003-07-16 20:59:33 +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="")
|
2003-07-07 16:18:52 +02:00
|
|
|
|
then MACLIST_DISPOSITION=REJECT is assumed.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>MACLIST_LOG_LEVEL
|
|
|
|
|
|
</b>- Added in Version 1.3.10<br>
|
|
|
|
|
|
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., MACLIST_LOG_LEVEL="").<br>
|
|
|
|
|
|
</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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
If you have a HA setup
|
|
|
|
|
|
with failover to another firewall, you should have
|
|
|
|
|
|
NEWNOTSYN=Yes on both firewalls. You should also select NEWNOTSYN=Yes
|
|
|
|
|
|
if you have asymmetric routing.<br>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>LOGNEWNOTSYN</b>
|
|
|
|
|
|
- Added in Version 1.3.6<br>
|
|
|
|
|
|
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 firewall.</li>
|
|
|
|
|
|
|
|
|
|
|
|
<li><b>DETECT_DNAT_ADDRS</b> - Added in Version 1.3.4<br>
|
|
|
|
|
|
If set to "Yes" or "yes", Shorewall will detect
|
|
|
|
|
|
the first IP address of the interface to the source zone and
|
|
|
|
|
|
will include this address in DNAT rules as the original destination
|
|
|
|
|
|
IP address. If set to "No" or "no", Shorewall will not detect
|
|
|
|
|
|
this address and any destination IP address will match the
|
|
|
|
|
|
DNAT rule. If not specified or empty, "DETECT_DNAT_ADDRS=Yes"
|
|
|
|
|
|
is assumed.<br>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><b>MULTIPORT</b>
|
|
|
|
|
|
- (Removed in version 1.4.6 -- the value of this parameter is now automatically
|
|
|
|
|
|
detected by Shorewall)<br>
|
|
|
|
|
|
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
|
|
|
|
|
|
file that meets these criteria:<br>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li>No port range(s)
|
|
|
|
|
|
specified</li>
|
|
|
|
|
|
<li>Specifies
|
2003-07-07 16:18:52 +02:00
|
|
|
|
15 or fewer ports</li>
|
2003-06-18 22:03:19 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-06-18 22:03:19 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Rules not meeting those criteria will continue to generate an individual
|
|
|
|
|
|
rule for each listed port or port range.
|
|
|
|
|
|
</p>
|
|
|
|
|
|
</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.
|
2003-07-07 16:18:52 +02:00
|
|
|
|
Example: SUBSYSLOCK=/var/lock/subsys/shorewall.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<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.
|
2003-07-07 16:18:52 +02:00
|
|
|
|
</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
</b> and <b> LOGBURST</b><br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
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 assumed.</li>
|
|
|
|
|
|
<li><b>NAT_ENABLED</b>
|
|
|
|
|
|
(Removed in Shorewall 1.4.6 -- the value of this parameter is now automatically
|
|
|
|
|
|
detected by Shorewall)<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>
|
|
|
|
|
|
(Removed in Shorewall 1.4.6 -- the value of this parameter is now automatically
|
|
|
|
|
|
detected by Shorewall)<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 (/proc/sys/net/ipv4/ip_forward).
|
|
|
|
|
|
Possible values are:<br>
|
|
|
|
|
|
<br>
|
|
|
|
|
|
On or
|
2003-07-07 16:18:52 +02:00
|
|
|
|
on - packet forwarding will be enabled.<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
Off or
|
|
|
|
|
|
off - packet forwarding will be disabled.<br>
|
|
|
|
|
|
Keep
|
|
|
|
|
|
or keep - Shorewall will neither enable nor disable
|
2003-07-07 16:18:52 +02:00
|
|
|
|
packet forwarding.<br>
|
2003-07-16 20:59:33 +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 versions before
|
|
|
|
|
|
1.4.6 can only add addresses to the first subnetwork configured on
|
|
|
|
|
|
an interface.<br>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
If this variable
|
2003-07-16 20:59:33 +02:00
|
|
|
|
is not set or is given an empty value (ADD_IP_ALIASES="")
|
2003-07-07 16:18:52 +02:00
|
|
|
|
then ADD_IP_ALIASES=Yes is assumed.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>ADD_SNAT_ALIASES</b><br>
|
|
|
|
|
|
This parameter
|
|
|
|
|
|
determines whether Shorewall automatically adds the
|
|
|
|
|
|
SNAT <i> ADDRESS </i>in <a 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 versions before 1.4.6 can only add addresses to
|
2003-07-07 16:18:52 +02:00
|
|
|
|
the first subnetwork configured on an interface.<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<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
|
2003-06-18 22:03:19 +02:00
|
|
|
|
href="kernel.htm">in your kernel</a>.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>ROUTE_FILTER</b><br>
|
|
|
|
|
|
If this parameter
|
|
|
|
|
|
is given the value "Yes" or "yes" then route filtering
|
|
|
|
|
|
(anti-spoofing) is enabled on all network interfaces.
|
|
|
|
|
|
The default value is "no".</li>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<h2><a name="modules"></a> /etc/shorewall/modules Configuration</h2>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<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>
|
|
|
|
|
|
above).</p>
|
|
|
|
|
|
|
|
|
|
|
|
<p>The file that is released with Shorewall calls the Shorewall function
|
|
|
|
|
|
"loadmodule" for the set of modules that I load.</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>The <i>loadmodule</i> function is called as follows:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>loadmodule <i><modulename> </i>[
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<i> <module parameters> </i>]</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>where</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2003-01-14 18:18:42 +01:00
|
|
|
|
<p><i><modulename> </i></p>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p>is the name of the modules without the trailing ".o" (example ip_conntrack).</p>
|
|
|
|
|
|
</blockquote>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p><i> <module parameters></i></p>
|
2003-07-04 18:41:22 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Optional parameters to the insmod utility.</p>
|
2003-07-16 20:59:33 +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 is executed:</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> insmod <i>moduledirectory</i>/<i><modulename></i>.o <i><module
|
|
|
|
|
|
parameters></i></p>
|
|
|
|
|
|
</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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
modules and execute the following command:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<p> insmod <i>moduledirectory/<modulename>.</i>o.gz <<i>module
|
|
|
|
|
|
parameters></i></p>
|
|
|
|
|
|
</blockquote>
|
|
|
|
|
|
|
2003-04-13 17:28:32 +02:00
|
|
|
|
<h2><a name="TOS"></a> /etc/shorewall/tos Configuration</h2>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<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 this file to be processed
|
|
|
|
|
|
by Shorewall, you must have <a href="#MangleEnabled">mangle
|
|
|
|
|
|
support enabled</a> .</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Entries in the file have the following columns:</p>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +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 <a
|
2003-06-18 22:03:19 +02:00
|
|
|
|
href="configuration_file_basics.htm#MAC">in </a><a
|
2003-07-16 20:59:33 +02:00
|
|
|
|
href="configuration_file_basics.htm#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 a protocol in /etc/protocols or the
|
|
|
|
|
|
protocol's number.</li>
|
|
|
|
|
|
<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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
-- The type of service. Must be one of the following:</li>
|
|
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p> Minimize-Delay (16)<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
Maximize-Throughput
|
2003-07-07 16:18:52 +02:00
|
|
|
|
(8)<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
Maximize-Reliability
|
|
|
|
|
|
(4)<br>
|
|
|
|
|
|
Minimize-Cost
|
2003-07-07 16:18:52 +02:00
|
|
|
|
(2)<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
Normal-Service
|
|
|
|
|
|
(0)</p>
|
|
|
|
|
|
</blockquote>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
</blockquote>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<p> The /etc/shorewall/tos file that is included with Shorewall contains
|
|
|
|
|
|
the following entries.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="2" cellpadding="2" style="border-collapse: collapse;">
|
2003-07-16 20:59:33 +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
|
2003-07-07 16:18:52 +02:00
|
|
|
|
PORT(S)</b></td>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<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>
|
2003-07-16 20:59:33 +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
|
|
|
|
|
|
file. </p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<h2><a name="Blacklist"></a>/etc/shorewall/blacklist</h2>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<p>Each line in
|
|
|
|
|
|
/etc/shorewall/blacklist
|
|
|
|
|
|
contains
|
|
|
|
|
|
an IP
|
|
|
|
|
|
address, a MAC address in <a
|
|
|
|
|
|
href="configuration_file_basics.htm#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>
|
2003-07-16 20:59:33 +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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
network.<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<p>Beginning with Shorewall 1.3.8, the blacklist file has three columns:<br>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</p>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<ul>
|
|
|
|
|
|
<li><b>ADDRESS/SUBNET
|
|
|
|
|
|
- </b>As described above.</li>
|
|
|
|
|
|
<li><b>PROTOCOL</b>
|
|
|
|
|
|
- Optional. If specified, only packets specifying
|
|
|
|
|
|
this protocol will be blocked.</li>
|
|
|
|
|
|
<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>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</ul>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<p>Shorewall also has a <a href="blacklisting_support.htm">dynamic blacklist
|
|
|
|
|
|
capability.</a></p>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
|
2003-07-16 20:59:33 +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, I suggest that you install and configure
|
|
|
|
|
|
Squid (<a href="http://www.squid-cache.org">http://www.squid-cache.org</a>).
|
|
|
|
|
|
</b></font></p>
|
|
|
|
|
|
|
|
|
|
|
|
<h2><a name="rfc1918"></a>/etc/shorewall/rfc1918 (Added in Version 1.3.1)</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>This file lists the subnets affected by the <a href="#Interfaces"><i>norfc1918</i>
|
|
|
|
|
|
interface option</a>. Columns in the file are:</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>SUBNET</b>
|
|
|
|
|
|
- The subnet using VLSM notation (e.g., 192.168.0.0/16).</li>
|
|
|
|
|
|
<li><b>TARGET<i>
|
|
|
|
|
|
</i></b>- What to do with packets to/from the
|
|
|
|
|
|
SUBNET:
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +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>
|
|
|
|
|
|
parameter above.</li>
|
|
|
|
|
|
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</li>
|
|
|
|
|
|
|
2003-05-15 21:39:23 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
|
|
|
|
|
<h2><a name="Routestopped"></a>/etc/shorewall/routestopped (Added in Version
|
|
|
|
|
|
1.3.4)</h2>
|
|
|
|
|
|
|
|
|
|
|
|
<p>This file defines the hosts that are accessible from the firewall when
|
|
|
|
|
|
the firewall is stopped. Columns in the file
|
|
|
|
|
|
are:</p>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<ul>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>INTERFACE
|
|
|
|
|
|
</b>- The firewall interface through which the
|
2003-07-07 16:18:52 +02:00
|
|
|
|
host(s) comminicate with the firewall.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
<li><b>HOST(S)
|
|
|
|
|
|
</b>- (Optional) - A comma-separated list of IP/Subnet
|
|
|
|
|
|
addresses. If not supplied or supplied as "-" then 0.0.0.0/0
|
2003-07-07 16:18:52 +02:00
|
|
|
|
is assumed.</li>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
|
2003-05-15 21:39:23 +02:00
|
|
|
|
</ul>
|
2003-07-16 20:59:33 +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 interfaces through eth1 and your local
|
|
|
|
|
|
hosts through eth2.</p>
|
|
|
|
|
|
|
|
|
|
|
|
<blockquote>
|
|
|
|
|
|
|
2002-09-16 19:13:10 +02:00
|
|
|
|
<table border="2" style="border-collapse: collapse;" id="AutoNumber1"
|
|
|
|
|
|
cellpadding="2">
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +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>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
This file is described
|
|
|
|
|
|
in the <a href="MAC_Validation.html">MAC Validation Documentation</a>.<br>
|
|
|
|
|
|
|
2003-02-25 20:24:41 +01:00
|
|
|
|
<h2><a name="ECN"></a>/etc/shorewall/ecn (Added in Version 1.4.0)</h2>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
This file is described
|
|
|
|
|
|
in the <a href="ECN.html">ECN Control Documentation</a>.<br>
|
|
|
|
|
|
|
|
|
|
|
|
<p><font size="-1"> Updated 6/28/2003 - <a href="support.htm">Tom Eastep</a>
|
|
|
|
|
|
</font></p>
|
|
|
|
|
|
|
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>
|
2003-07-16 20:59:33 +02:00
|
|
|
|
</p>
|
|
|
|
|
|
<br>
|
2003-07-07 16:18:52 +02:00
|
|
|
|
<br>
|
|
|
|
|
|
<br>
|
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2002-09-16 19:13:10 +02:00
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