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Dear Malcolm,<br>
<br>
I don't believe there is any demand for this because the NAT Network
mode was never intended to be used this way.<br>
It really is just an easy way to put a bunch of VMs on a host within
their own network and hide them from the external world.<br>
<br>
While what you want to do is normal and standard, it's definitely
not the use case for NAT Network mode.<br>
A typical setup would be a dedicated VM acting as a router/NAT
Engine instead of the NAT Network process, VM that you can configure
and that will do all the work.<br>
That dedicated VM would have a bridged interface on the physical NIC
of the host. Another typical setup would be to replace the dedicated
router VM by the host itself - you would then configure NAT and IP
Routing on the host using iptables and your router VM for the hidden
network would have a host-only interface.<br>
<br>
I'll let the devs confirmed I'm not saying anything stupid here :)<br>
<br>
Max<br>
<br>
<div class="moz-cite-prefix">On 04/10/16 11:01, Malcolm Clarke
wrote:<br>
</div>
<blockquote
cite="mid:FBB6BBACC666694F892E994A40E2714956BA3F03@v-ex10mb3.academic.windsor"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<p>Dear Maxine</p>
<p>The topology would be as follows</p>
<pre>Public |--------| VBox NAT Network process |Private Network 1 10.0.2.0| Router VM |Private Network 2 10.0.3.
0</pre>
<br>
With a routable private network behind the NAT router. This is
industry standard.<br>
<br>
However the NAT router needs sufficient information to deliver
incoming packets other than for its own subnet to another router,
either because it has static routes, default router or understand
RIP. This is normal.<br>
<br>
I understand that the NAT network process is intended to be simple
and support basic functionality, however my topology is industry
standard, and others may wish to do training, etc on this type of
configuration.<br>
<br>
I would be content with the most basic support, eg default router.
However I do not know the demand for this.<br>
<br>
Regards<br>
<br>
Malcolm<br>
<br>
<br>
<br>
<div class="moz-cite-prefix">On 04/10/2016 09:34, Maxime Dor
wrote:<br>
</div>
<blockquote
cite="mid:d3912677-efc6-4aac-8d9b-5bb24bcdc7df@kamax.io"
type="cite">
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">
<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
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