2003-02-04 16:26:02 +01:00
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<meta http-equiv="Content-Type"
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content="text/html; charset=windows-1252">
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2003-03-08 03:28:47 +01:00
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<title>OpenVPN Tunnels</title>
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2003-02-04 16:26:02 +01:00
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<meta name="GENERATOR" content="Microsoft FrontPage 5.0">
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<meta name="ProgId" content="FrontPage.Editor.Document">
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2003-12-03 00:51:46 +01:00
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<body>
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<h1 style="text-align: center;">OpenVPN Tunnels<br>
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</h1>
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<p>OpenVPN is a robust and highly configurable VPN (Virtual Private
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Network) daemon which can be used to securely link two or more private
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networks using an encrypted tunnel over the internet. OpenVPN is an
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Open Source project and is <a
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href="http://openvpn.sourceforge.net/license.html">licensed under the
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GPL</a>. OpenVPN can be downloaded from <a
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2003-02-04 16:26:02 +01:00
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href="http://openvpn.sourceforge.net/">http://openvpn.sourceforge.net/</a>.<br>
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2003-12-03 00:51:46 +01:00
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</p>
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2003-02-04 16:26:02 +01:00
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<p>OpenVPN support was added to Shorewall in version 1.3.14.<br>
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2003-12-03 00:51:46 +01:00
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</p>
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2003-02-04 16:26:02 +01:00
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<h2>Bridging two Masqueraded Networks</h2>
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<p>Suppose that we have the following situation:</p>
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<p align="center"><img border="0" src="images/TwoNets1.png" width="745"
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2003-12-03 00:51:46 +01:00
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height="427"> </p>
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<p align="left">We want systems in the 192.168.1.0/24 subnetwork to be
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able to communicate with the systems in the 10.0.0.0/8 network. This is
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accomplished through use of the /etc/shorewall/tunnels file and the
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/etc/shorewall/policy file and OpenVPN.</p>
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<p align="left">While it was possible to use the Shorewall start and
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stop script to start and stop OpenVPN, I decided to use the init script
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of OpenVPN to start and stop it.</p>
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<p align="left">On each firewall, you will need to declare a zone to
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represent the remote subnet. We'll assume that this zone is called
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'vpn' and declare it in /etc/shorewall/zones on both systems as follows.</p>
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<blockquote>
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<table border="2" cellpadding="2" style="border-collapse: collapse;">
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<tbody>
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<tr>
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<td><strong>ZONE</strong></td>
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<td><strong>DISPLAY</strong></td>
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<td><strong>COMMENTS</strong></td>
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</tr>
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<tr>
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<td>vpn</td>
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<td>VPN</td>
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<td>Remote Subnet</td>
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</tr>
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</tbody>
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2003-02-04 16:26:02 +01:00
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</table>
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2003-12-03 00:51:46 +01:00
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</blockquote>
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<p align="left">On system A, the 10.0.0.0/8 will comprise the <b>vpn</b>
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zone.
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2003-07-16 20:59:33 +02:00
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In /etc/shorewall/interfaces:</p>
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<blockquote>
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<table border="2" cellpadding="2" style="border-collapse: collapse;">
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<tbody>
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<tr>
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<td><b>ZONE</b></td>
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<td><b>INTERFACE</b></td>
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<td><b>BROADCAST</b></td>
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<td><b>OPTIONS</b></td>
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</tr>
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<tr>
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<td>vpn</td>
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<td>tun0</td>
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<td><br>
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</td>
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<td> </td>
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</tr>
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</tbody>
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2003-02-04 16:26:02 +01:00
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</table>
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2003-12-03 00:51:46 +01:00
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</blockquote>
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<p align="left">In /etc/shorewall/tunnels on system A, we need the
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following:</p>
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<blockquote>
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<table border="2" cellpadding="2" style="border-collapse: collapse;">
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<tbody>
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<tr>
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<td><b>TYPE</b></td>
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<td><b>ZONE</b></td>
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<td><b>GATEWAY</b></td>
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<td><b>GATEWAY ZONE</b></td>
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</tr>
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<tr>
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<td>openvpn</td>
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<td>net</td>
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<td>134.28.54.2</td>
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<td> </td>
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</tr>
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</tbody>
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2003-02-04 16:26:02 +01:00
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</table>
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2003-12-03 00:51:46 +01:00
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</blockquote>
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<p>This entry in /etc/shorewall/tunnels opens the firewall so that
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OpenVPN traffic on the default port 5000/udp will be accepted to/from
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the remote gateway. If you change the port used by OpenVPN to 7777, you
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can define /etc/shorewall/tunnels like this:<br>
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</p>
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<blockquote>
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<table border="2" cellpadding="2" style="border-collapse: collapse;">
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<tbody>
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<tr>
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<td><b>TYPE</b></td>
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<td><b>ZONE</b></td>
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<td><b>GATEWAY</b></td>
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<td><b>GATEWAY ZONE</b></td>
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</tr>
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<tr>
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<td>openvpn:7777</td>
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<td>net</td>
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<td>134.28.54.2</td>
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<td> </td>
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</tr>
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</tbody>
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2003-02-04 16:26:02 +01:00
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</table>
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2003-12-03 00:51:46 +01:00
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</blockquote>
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2003-02-04 16:26:02 +01:00
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<p>This is the OpenVPN config on system A:</p>
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<blockquote>
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2003-02-04 16:26:02 +01:00
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<p></p>
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2003-12-03 00:51:46 +01:00
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</blockquote>
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<blockquote>
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<p>dev tun<br>
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local 206.162.148.9<br>
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remote 134.28.54.2<br>
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ifconfig 192.168.99.1 192.168.99.2<br>
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up ./route-a.up<br>
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tls-server<br>
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dh dh1024.pem<br>
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ca ca.crt<br>
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cert my-a.crt<br>
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key my-a.key<br>
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comp-lzo<br>
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verb 5<br>
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</p>
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</blockquote>
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<p>Similarly, On system B the 192.168.1.0/24 subnet will comprise the <b>vpn</b>
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zone. In /etc/shorewall/interfaces:</p>
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<blockquote>
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2003-02-04 16:26:02 +01:00
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<table border="2" cellpadding="2" style="border-collapse: collapse;">
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2003-12-03 00:51:46 +01:00
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<tbody>
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<tr>
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<td><b>ZONE</b></td>
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<td><b>INTERFACE</b></td>
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<td><b>BROADCAST</b></td>
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<td><b>OPTIONS</b></td>
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</tr>
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<tr>
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<td>vpn</td>
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<td>tun0</td>
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<td>192.168.1.255</td>
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<td> </td>
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</tr>
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</tbody>
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2003-02-04 16:26:02 +01:00
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</table>
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2003-12-03 00:51:46 +01:00
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</blockquote>
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2003-02-04 16:26:02 +01:00
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<p>In /etc/shorewall/tunnels on system B, we have:</p>
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<blockquote>
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<table border="2" cellpadding="2" style="border-collapse: collapse;">
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<tbody>
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<tr>
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<td><b>TYPE</b></td>
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<td><b>ZONE</b></td>
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<td><b>GATEWAY</b></td>
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<td><b>GATEWAY ZONE</b></td>
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</tr>
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<tr>
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<td>openvpn</td>
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<td>net</td>
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<td>206.191.148.9</td>
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<td> </td>
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</tr>
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</tbody>
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2003-02-04 16:26:02 +01:00
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</table>
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2003-12-03 00:51:46 +01:00
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</blockquote>
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<p>And in the OpenVPN config on system B:</p>
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<blockquote>
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<p>dev tun<br>
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local 134.28.54.2<br>
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remote 206.162.148.9<br>
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ifconfig 192.168.99.2 192.168.99.1<br>
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up ./route-b.up<br>
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tls-client<br>
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ca ca.crt<br>
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cert my-b.crt<br>
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key my-b.key<br>
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comp-lzo<br>
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verb 5<br>
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</p>
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</blockquote>
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<p align="left">You will need to allow traffic between the "vpn" zone
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and the "loc" zone on both systems -- if you simply want to admit all
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traffic in both directions, you can use the policy file:</p>
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<blockquote>
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2003-02-04 16:26:02 +01:00
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<table border="2" cellpadding="2" style="border-collapse: collapse;">
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2003-12-03 00:51:46 +01:00
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<tbody>
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<tr>
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<td><strong>SOURCE</strong></td>
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<td><strong>DEST</strong></td>
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<td><strong>POLICY</strong></td>
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<td><strong>LOG LEVEL</strong></td>
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</tr>
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<tr>
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<td>loc</td>
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<td>vpn</td>
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<td>ACCEPT</td>
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<td> </td>
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</tr>
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<tr>
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<td>vpn</td>
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<td>loc</td>
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<td>ACCEPT</td>
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<td> </td>
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</tr>
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</tbody>
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2003-02-04 16:26:02 +01:00
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</table>
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2003-12-03 00:51:46 +01:00
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</blockquote>
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<p>On both systems, restart Shorewall and start OpenVPN. The systems in
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the two masqueraded subnetworks can now talk to each other.</p>
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<p><font size="2">Updated 2/4/2003 - <a href="support.htm">Tom Eastep</a></font>
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2003-02-04 16:26:02 +01:00
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<small>and Simon Mater</small><br>
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2003-12-03 00:51:46 +01:00
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</p>
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2003-03-08 03:28:47 +01:00
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<p><font size="2"> </font></p>
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<p><font face="Trebuchet MS"><a href="copyright.htm"><font size="2">Copyright</font>
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<EFBFBD> <font size="2">2003 Thomas M. Eastep. and Simon Mater<br>
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</font></a></font></p>
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<br>
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<br>
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<br>
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<br>
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2003-02-04 16:26:02 +01:00
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</body>
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</html>
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