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I've got a machine with a single NIC. I'd like to set it it up like thus:

  • Dom0 listening on 192.168.x.1 and doing nothing but being Dom0
  • DomU on 192.168.x.2 and external ip assigned by dhcp doing firewall and NAT routing, and an nginx to push web requests into virtual machines
  • DomU on 192.168.x.n running web servers accepting requests

I can't get the virtual DomU router to route the traffic from the dom0 to the internets and back. Is this even possible with a single NIC? In that case, what configuration files should I post here for review?

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up vote 2 down vote accepted

Yes, this is possible in a couple of different ways. The "correct" way is with VLANs, but the chances of your upstream device supporting that are slim.

Instead, configure the domU with two virtual interfaces hooked into the same bridge on the dom0. Configure one vif to do DHCP to get the public IP and the other with the private IP, and configure it as a firewall.

Don't expect much in the way of security from this, and quite honestly I'd just go and buy a second NIC for the physical machine and be done with it -- less confusion all round.

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