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      <h1 align="center"><font color="#ffffff">IPSEC Tunnels</font></h1>
       </td>
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<h2><font color="#660066">Configuring FreeS/Wan</font></h2>
  There is an excellent guide to configuring IPSEC tunnels at<a
 href="http://jixen.tripod.com">  http://jixen.tripod.com</a> . I highly recommend
that you consult that site for information about confuring FreeS/Wan.� 
<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>
    
<p>In /etc/shorewall/init, include:</p>
    
<p>���� qt service ipsec stop</p>
    
<p>In /etc/shorewall/start, include:</p>
    
<p>��� qt service ipsec start</p>
    
<h2>  <font color="#660066">IPSec Gateway on the Firewall System   </font></h2>
               
<p>Suppose that we have the following sutuation:</p>
             <font color="#660066">             
<p align="center"><font face="Century Gothic, Arial, Helvetica"> <img
 src="images/TwoNets1.png" width="745" height="427">
         </font></p>
               </font>             
<p align="left">We want systems in the 192.168.1.0/24 sub-network to be able 
to communicate with systems in the 10.0.0.0/8 network.</p>
              
<p align="left">To make this work, we need to do two things:</p>
              
<p align="left">a) Open the firewall so that the IPSEC tunnel can be established 
 (allow the ESP and AH protocols and UDP Port 500). </p>
              
<p align="left">b) Allow traffic through the tunnel.</p>
              
<p align="left">Opening the firewall for the IPSEC tunnel is accomplished 
by  adding an entry to the /etc/shorewall/tunnels file.</p>
              
<p align="left">In /etc/shorewall/tunnels  on system A, we need the following�</p>
              
<blockquote>       
  <table border="2" cellpadding="2" style="border-collapse: collapse;">
            <tbody>
               <tr>
                <td><strong>  TYPE</strong></td>
                <td><strong>  ZONE</strong></td>
                <td><strong>  GATEWAY</strong></td>
                <td><strong>  GATEWAY ZONE</strong></td>
            </tr>
            <tr>
                <td>ipsec</td>
                <td>net</td>
                <td>134.28.54.2</td>
                <td>�</td>
            </tr>
                             
    </tbody>               
  </table>
 </blockquote>
                  
<p align="left">In /etc/shorewall/tunnels on system B, we would have:</p>
                  
<blockquote>         
  <table border="2" cellpadding="2" style="border-collapse: collapse;">
            <tbody>
                 <tr>
                <td><strong>  TYPE</strong></td>
                <td><strong>  ZONE</strong></td>
                <td><strong>  GATEWAY</strong></td>
                <td><strong>  GATEWAY ZONE</strong></td>
            </tr>
            <tr>
                <td>ipsec</td>
                <td>net</td>
                <td>206.161.148.9</td>
            <td>�</td>
            </tr>
                                 
    </tbody>                   
  </table>
 </blockquote>
                     
<p align="left"><b>Note: </b>If either of the endpoints is behind a NAT gateway
then the tunnels file entry on the <u><b>other</b></u> endpoint should specify
a tunnel type of <i>ipsecnat</i> rather than <i>ipsec</i> and the GATEWAY
address should specify the external address of the NAT gateway.<br>
</p>
<p align="left">You need to define a zone for the remote subnet or include 
     it in your local zone. In this example, we'll assume that you have created 
a      zone called "vpn" to represent the remote subnet.</p>
                      
<blockquote>        
  <table border="2" cellpadding="2" style="border-collapse: collapse;">
                 <tbody>
       <tr>
                <td><strong>ZONE</strong></td>
                <td><strong>DISPLAY</strong></td>
                <td><strong>COMMENTS</strong></td>
            </tr>
            <tr>
                <td>vpn</td>
                <td>VPN</td>
                <td>Remote Subnet</td>
            </tr>
                               
    </tbody>   
  </table>
   </blockquote>
                     
<p align="left">At both systems, ipsec0 would be included in /etc/shorewall/interfaces 
as a "vpn" interface:</p>
                      
<blockquote>           
  <table border="2" cellpadding="2" style="border-collapse: collapse;">
            <tbody>
                   <tr>
                <td><strong>  ZONE</strong></td>
                <td><strong>  INTERFACE</strong></td>
                <td><strong>  BROADCAST</strong></td>
                <td><strong>  OPTIONS</strong></td>
            </tr>
            <tr>
                <td>vpn</td>
                <td>ipsec0</td>
                <td>�</td>
                <td>�</td>
            </tr>
                                     
    </tbody>                       
  </table>
 </blockquote>
                          
<p align="left"> You will need to allow traffic between the "vpn" zone and 
       the "loc" zone -- if you simply want to admit all traffic in both 
      directions, you can use the policy file:</p>
                                 
<blockquote>            
  <table border="2" cellpadding="2" style="border-collapse: collapse;">
                 <tbody>
       <tr>
                <td><strong>SOURCE</strong></td>
                <td><strong>DEST</strong></td>
                <td><strong>POLICY</strong></td>
                <td><strong>LOG LEVEL</strong></td>
            </tr>
            <tr>
                <td>loc</td>
                <td>vpn</td>
                <td>ACCEPT</td>
            <td>�</td>
            </tr>
                                <tr>
                <td>vpn</td>
                <td>loc</td>
                <td>ACCEPT</td>
            <td>�</td>
            </tr>
                               
    </tbody>   
  </table>
   </blockquote>
                          
<p align="left"> Once you have these entries in place, restart Shorewall (type
shorewall restart);  you are now ready to configure the tunnel in <a
 href="http://www.xs4all.nl/%7Efreeswan/">  FreeS/WAN</a>  .</p>
                                 
<h2><font color="#660066"><a name="RoadWarrior"></a>  Mobile System (Road 
Warrior)</font></h2>
                          
<p>Suppose that you have a laptop system (B) that you take with you when you
travel and you want to be able to establish a secure connection back to your
local network.</p>
                          
<p align="center"><strong><font face="Century Gothic, Arial, Helvetica">
      <img src="images/Mobile.png" width="677" height="426">
               </font></strong></p>
                        
<p align="left">You need to define a zone for the laptop or include it in 
     your local zone. In this example, we'll assume that you have created 
a zone      called "vpn" to represent the remote host.</p>
                      
<blockquote>        
  <table border="2" cellpadding="2" style="border-collapse: collapse;">
                 <tbody>
       <tr>
                <td><strong>ZONE</strong></td>
                <td><strong>DISPLAY</strong></td>
                <td><strong>COMMENTS</strong></td>
            </tr>
            <tr>
                <td>vpn</td>
                <td>VPN</td>
                <td>Remote Subnet</td>
            </tr>
                               
    </tbody>   
  </table>
   </blockquote>
                          
<p align="left"> In this instance, the mobile system (B) has IP address 134.28.54.2 
but that cannot be determined in advance. In the /etc/shorewall/tunnels file 
on system A, the following entry should be made:</p>
                          
<blockquote>             
  <table border="2" cellpadding="2" style="border-collapse: collapse;">
            <tbody>
                     <tr>
                <td><strong>  TYPE</strong></td>
                <td><strong>  ZONE</strong></td>
                <td><strong>  GATEWAY</strong></td>
                <td><strong>  GATEWAY ZONE</strong></td>
            </tr>
            <tr>
                <td>ipsec</td>
                <td>net</td>
                <td>0.0.0.0/0</td>
                <td>vpn</td>
            </tr>
                                         
    </tbody>                           
  </table>
 </blockquote>
                              
<p>Note that the GATEWAY ZONE column contains the name of the zone corresponding 
to peer subnetworks. This indicates that the gateway system itself comprises 
the peer subnetwork; in other words, the remote gateway is a standalone system.</p>
                                      
<p>You will need to configure /etc/shorewall/interfaces and establish    
     your "through the tunnel" policy as shown under the first example above.<br>
 </p>
 
<h2><a name="Dynamic"></a>Dynamic RoadWarrior Zones</h2>
 Beginning with Shorewall release 1.3.10, you can define multiple VPN zones 
and add and delete remote endpoints dynamically using /sbin/shorewall. In 
/etc/shorewall/zones:<br>
 <br>
 
<blockquote>   
  <table cellpadding="2" border="2" style="border-collapse: collapse;">
     <tbody>
       <tr>
         <td valign="top"><b>ZONE<br>
         </b></td>
         <td valign="top"><b>DISPLAY<br>
         </b></td>
         <td valign="top"><b>COMMENTS<br>
         </b></td>
       </tr>
       <tr>
         <td valign="top">vpn1<br>
         </td>
         <td valign="top">VPN-1<br>
         </td>
         <td valign="top">First VPN Zone<br>
         </td>
       </tr>
       <tr>
         <td valign="top">vpn2<br>
         </td>
         <td valign="top">VPN-2<br>
         </td>
         <td valign="top">Second VPN Zone<br>
         </td>
       </tr>
       <tr>
         <td valign="top">vpn3<br>
         </td>
         <td valign="top">VPN-3<br>
         </td>
         <td valign="top">Third VPN Zone<br>
         </td>
       </tr>
     
    </tbody>   
  </table>
   <br>
 </blockquote>
 In /etc/shorewall/tunnels:<br>
 
<blockquote>   
  <table cellpadding="2" cellspacing="" border="2"
 style="border-collapse: collapse;">
     <tbody>
       <tr>
         <td valign="top"><b>TYPE<br>
         </b></td>
         <td valign="top"><b>ZONE<br>
         </b></td>
         <td valign="top"><b>GATEWAY<br>
         </b></td>
         <td valign="top"><b>GATEWAY ZONE<br>
         </b></td>
       </tr>
       <tr>
         <td valign="top">ipsec<br>
         </td>
         <td valign="top">net<br>
         </td>
         <td valign="top">0.0.0.0/0<br>
         </td>
         <td valign="top">vpn1,vpn2,vpn3<br>
         </td>
       </tr>
     
    </tbody>   
  </table>
   <br>
 </blockquote>
 When Shorewall is started, the zones vpn[1-3] will all be empty and Shorewall 
will issue warnings to that effect. These warnings may be safely ignored. 
FreeS/Wan may now be configured to have three different Road Warrior connections 
with the choice of connection being based on X-509 certificates or some other 
means. Each of these connectioins will utilize a different updown script that
adds the remote station to the appropriate zone when the connection comes
up and that deletes the remote station when the connection comes down. For
example, when 134.28.54.2 connects for the vpn2 zone the 'up' part of the
script will issue the command":<br>
 <br>
 
<blockquote>/sbin/shorewall add ipsec0:134.28.54.2 vpn2<br>
 </blockquote>
 and the 'down' part will:<br>
 
<blockquote>/sbin/shorewall delete ipsec0:134.28.54.2 vpn</blockquote>
                                      
<p><font size="2">Last updated 10/23/2002 - </font><font size="2">       
 <a href="support.htm">Tom Eastep</a></font>  </p>
                                      
<p><a href="copyright.htm"><font size="2">     
   Copyright</font> � <font size="2">2001, 2002 Thomas M. Eastep.</font></a></p>
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