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    Malcolm,<br>
    <br>
    Just to be clear, is this your topology?<br>
    <blockquote>
      <pre>Public |--------| VBox NAT Network process |---------| Router VM |---------| Hidden network</pre>
    </blockquote>
    If so, I'm not aware of options to include static routes into the
    NAT engine of VirtualBox, but I also don't see why you would need
    to.<br>
    it's the job of the router VM to also do NAT to hide that final
    network, else you need the "public" routers to know about that
    hidden network but that defeats the point of using NAT in the first
    place.<br>
    If this is your topology, I feel you're just using the wrong tool
    for the job.<br>
    <br>
    If your topology is different, let us know and we'll help further!<br>
    <br>
    <div class="moz-cite-prefix">On 03/10/16 22:34, Malcolm Clarke
      wrote:<br>
    </div>
    <blockquote
cite="mid:FBB6BBACC666694F892E994A40E2714956BA3DFD@v-ex10mb3.academic.windsor"
      type="cite">
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      <p>Dear Maxine</p>
      <p>The problem is that a packet can eminate from a VM on the
        hidden subnet and is correctly routed by the internal router to
        the NAT router (the internal server contains the NAT as its
        default router), and so the packet is sent to the public
        network. The NAT router will correctly create an entry in the
        mapping table with the return IP address. However when a packet
        returns from the public network, even though the NAT router can
        substitute the correct destination IP address for the hidden
        subnet, it does not have the routing information to deliver the
        packet to the internal router for it to be returned to the VM on
        the hidden network.</p>
      <p>It would therefore require some simple mechanism to add static
        routes (or private side default gateway) to the NAT router.</p>
      <p>Using a bridge will not work as that would require configuring
        "public" routers to deliver packets to the internal router. NAT
        is the best solution.<br>
      </p>
      <p>Regards</p>
      <p>Malcolm<br>
      </p>
      <br>
      <div class="moz-cite-prefix">On 03/10/2016 13:58, Maxime Dor
        wrote:<br>
      </div>
      <blockquote
        cite="mid:5711fe0c-e7f8-ff8b-cf4c-c7fe58b21453@kamax.io"
        type="cite">
        Hi Malcom,<br>
        <br>
        That is on purpose - being behind a NAT network means you want
        to hide any subnet connect to that network from the outside
        world.<br>
        Any outgoing connection will look like it came from the NAT
        Router "public" IP.<br>
        If you want to allow specific connections to be allowed in, you
        need to configure port forward - so far, I don't think I tell
        you anything new.<br>
        <br>
        But if you need the "outside" world to know about "inside"
        networks, then NAT is not the right choice. You need to switch
        to a non-NAT solution like Bridged mode (or Host-Only with
        routing enabled on the host) and the "outside" world needs to
        know about those "inside" network with two possibilities:<br>
        - Static routes on all routers that need to deal with those
        subnets<br>
        - Internal routing protocol like RIP, EIGRP or OSPF that will
        auto-detect routes and populate routing tables of routers.<br>
        <br>
        <div class="moz-cite-prefix">On 03/10/16 13:30, Malcolm Clarke
          wrote:<br>
        </div>
        <blockquote
cite="mid:FBB6BBACC666694F892E994A40E2714956BA3BD5@v-ex10mb3.academic.windsor"
          type="cite">
          Dear Development Group<br>
          <br>
          I am trying to demonstrate routing in a virtualised network
          created using VirtualBox with a FreeBSD server acting as
          router between 2 virtual networks. One network is set as NAT
          Network to allow access to outside world. However, although
          packets can be directed from the router to the NAT router for
          outward delivery, the NAT router does not know how to deliver
          the incoming packets for the "hidden" subnet.<br>
          <br>
          I wonder if anyone has modified the NAT network to allow
          simple static routes or default gateway to support this
          cnfiguration.<br>
          <br>
          I do not know the interest for this functionality and whether
          the work is justified for the use that would be made.<br>
          <br>
          Regards<br>
          <br>
          Malcolm<br>
          <br>
          <br>
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                <b><span style="color:#C0504D">Malcolm Clarke </span></b><span
                  style="font-size:10.0pt;color:#C0504D">BSc (Hons), PhD</span></p>
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                <span style="color:#1F497D">Reader in Telemedicine and
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          <pre wrap="">_______________________________________________
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</pre>
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        <pre wrap="">_______________________________________________
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            <b><span style="color:#C0504D">Malcolm Clarke </span></b><span
              style="font-size:10.0pt;color:#C0504D">BSc (Hons), PhD</span></p>
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            </span><span style="color:#1F497D" lang="DE">+44 (0) 1895
              265053</span></p>
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            <span style="color:#C0504D">College of Engineering, Design
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