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I've got a Win2k8 standard server running Hyper-V with a Server 2003 web guest instance running. The host is publicly available on the internet.

I've created an Internal Private network in the Hyper-V Virtual Network manager. I've set the host IP for that virtual adapter to 192.168.0.1. I've set the IP on the guest to 192.168.0.2. They can ping each other and share files. I can't browse the web on the guest though. NSLOOKUPs are working. I've tried setting the DNS server setting on the guest to 192.168.0.1 and something external like Google's 8.8.8.8 server to no avail.

Windows firewall is disabled on the internal virtual network.

I've tried it with both DNS installed on the host and without it.

I'm not sure which RRAS/NAT settings are relevant to pass on so ask if you need me to clarify anything.

How do I get outbound internet working on the guest VM?

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3 Answers

Can you ping anything outside of the private network? If you can't then you are missing the default gateway/RRAS. Most likely you will need to enable RRAS on your host to provide routing services. It's silly easy to install and get working.

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I cannot ping outside the local. But RRAS is up and running. –  Runscope API Tools Mar 29 '10 at 4:19
    
Did you also configure default routes and NAT on the RRAS instance? Without NAT configured.... it wil not do network address translation. –  TomTom Mar 29 '10 at 5:37
    
Good call @TomTom. This should help you out with your config. technet.microsoft.com/en-us/library/dd469812%28WS.10%29.aspx –  Dayton Brown Mar 29 '10 at 10:31
    
Well, you don't actually need to enable RRAS on the Hyper-V host to provide routing... doing so may just complicate the issue for someone not familiar with managing RRAS. You can simply update the Hyper-V host to enable routing on all interfaces and then configure the VM servers to route through the Hyper-V host... –  Dscoduc Apr 21 '10 at 18:22
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You mention an internal network of 192.168.0.1 for the Hyper-V host but nothing about whether the Hyper-V host has another interface that allows communication to the internet. It is usual practice to configure the Hyper-V host with an "external" interface that can communicate out to the internet, and then the internal interface that can communicate to the VM servers.

Your VM servers on the 192.168.0.x network will need a router to route the traffic through which can be another VM configured as a router or you can configure the Hyper-V host to be the router.

With the router configured you then need to set the VM machines default gateway to be the router IP address... that should get you going...

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I'm seeing a very similar problem. I have a host machine with a single guest. Both were working but then the guest suddenly lost contact with the outside world.

The physical machine has two interfaces. The first for the host, the second for the guest. The guest can ping the host but not the default gateway.

I repeat that this was working but during the comissioning process this has suddenly stopped working. I thought it was something I had done on the guest but I've eliminated this possibility by installing another guest from scratch and it too displays the same behaviour.

The host doesn't have a great deal running on it. Though I was in the process of configuring exchange when it failed. Exchange doesn't have anything magic which should interfere with network operation.

When the problem occured I was getting a 'general failure' when trying to ping the default gateway. I deinstalled pretty much everything, including the virtual interface, to no avail. After reinstalling a new network interface it still didn't work, though the symptoms changed. At the moment when I try to ping from the guest I get a message saying that it is unable to reach the host coming from the ip address of the guest machine.

This is obviously caused by something on the host, but I just can't see what it could be.

Anyone seen anything similar?

Ian

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