Can't get child server to hit the internet through Hyper-V

Posted on 2009-05-05
Last Modified: 2013-11-11
I have a Windows Server 2008 64-bit system with two NICs. The host/parent can hit the internet, but the only child machine, running Windows Server 2003, cannot. I have created two virtual networks, one for each adapter. One is internal, one is external. Both show as LAN connections in the client server (integration services have been successfully installed), but both connections show limited or no connectivity. I have read that internal networks need a child system to serve DHCP, but I would think the external network adapter/LAN should still work. Is DHCP not making it through from the parent to the child? Do I need to bridge the two VLANS? There is also talk of a virtual switch -- is this an actual control panel? I see nothing with that name.
Question by:wdabbs
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LVL 77

Expert Comment

by:Rob Williams
ID: 24309110
You should simply need to enable under "virtual network manager" on the host an external network connection, and name it. Then under settings for the child machine add a network adapter and choose the name of the one you created in the above. Assuming the DHCP server is enabled on the host or host LAN the child machine should receive an IP. If not try adding a static address in the same subnet as the host, though this should not be necessary. I would avoid using VLAN's until you have this working properly first.

Author Comment

ID: 24309198
I haven't enabled DHCP because the parent is on a domain run by another domain controller and I don't want to have two machines issuing DHCP. I suppose I can change the domain of the parent to its own domain to eliminate the possibility of conflict. But then the parent has to be a domain controller and I was hoping to avoid the extra overhead processing that would involve. Will the parent's DHCP server not issue DHCP to the child machines?
LVL 77

Expert Comment

by:Rob Williams
ID: 24309215
The parent will only issue a DHCP address to the child if the DHCP service is running on that machine. Can you assign the client a static address just to confirm DHCP is the only issue.?
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Author Comment

ID: 24309590
I assigned a static IP and turned off "Enable virtual LAN identification." After repairing the connection, I could hit the web. Thanks! So I could leave it static, or I could enable DHCP on the parent. But how do you do that without DHCP also going out to the parent domain? If I enable DHCP, it's going to try to issue it to everyone, is it not?
LVL 77

Accepted Solution

Rob Williams earned 500 total points
ID: 24310001
Since static works, I am surprised the child cannot get an IP from the existing DHCP server. You need a DHCP server somewhere on that LAN, but it should not have to be on the host. You are correct though it is not a good idea to have 2 DHCP servers on the same LAN, however it is possible to do so if you configure the scopes with non-conflicting IP ranges such as one being x.x.x.1-100, and the other x.x.x.101-200, still I don not recommend it. Have you tried DHCP with the existing configuration and VLAN's switched off?

Author Closing Comment

ID: 31578176
Apparently it was the VLAN setting that was causing the problem. I just now installed a virtual XP box on the same parent and it found the internet on the first try. After just now restarting the original child machine (server 2K3) that had the problem, it came back with an IP address conflict. Took off the static setting and it pulled an IP immediately upon a repair of the LAN. Thanks for your help finding the answer.
LVL 77

Expert Comment

by:Rob Williams
ID: 24331565
Glad to hear you were able to resolve. Thanks wdabbs.

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