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Question
Monday, June 17, 2019 5:18 AM
Trying to help a friend. I’ve got networking experience but not with Hyper-V.
Windows 2008 server with 4 Hyper-V servers – Domain controller, exchange, file and info.
His business scaled down years ago and he’s now running the server out of his apartment. The cable company recently changed his internet modem/router then the network stopped communicating. The management OS and VMs all had static IPs under a different subnet than the new modem. They initially tried setting the management OS to dynamic IP but that of course didn’t work. When they couldn’t get it to work, he called me. I changed the VM IP addresses to respective addresses on the new subnet. The settings for the NICs on the management OS are the question. I’ve tried a number of permutations, got it to work several times but it stopped working after rebooting the management OS.
3 Physical Network Ports
#1 & #2 are connected to a cable modem/router.
#3 is not used or configured.
1 Virtual Switch
#2 is bound to a Hyper-V external virtual switch. “Allow management operating system to share the network adapter” is enabled.
#2 properties, “Internet Protocol Version 4” is not selected. This seems odd but I figured it was part of Hyper-V so I left it alone.
Domain Controller VM
DNS=127.0.0.1
File Server VM, Email Server VM, Info Server VM
DNS=<IP of Domain Controller VM>
Gateway for all VMs=IP address that wasn’t assigned to anything. I believe this IP should either be assigned to #1 or the Virtual Switch. I’ve tried both with mixed results. When I assigned a static IP, I entered the cable modem IP as the gateway. When it came to the DNS settings, I wasn’t certain if it should be the cable modem IP or <IP of Domain Controller VM>. I’ve tried one, the other and both at the same time.
The issue is that the management OS (and the workstation) cannot see the VM servers to connect to them. I had it working several times but when I rebooted the management OS, it stopped working.
How should NIC #1 and/or the virtual switch be configured?
Should #2 have IP protocol?
Which one gets the static IP that the VMs use as Gateway?
Where should DNS point(cable modem or domain controller)?
To complicate matters a little more…prior to switching the cable modem/router he had a Linksys wireless router in between the server and cable modem/router. I believe that the Linksys router was operating on different subnet than the cable modem. He said the Linksys wifi stopped working so they tried resetting it(which lost all settings) then could never get it to work. I bring this up because I’m not certain if it was there would be a purpose for a different subnet.
Any insight would be appreciated.
All replies (3)
Monday, June 17, 2019 1:17 PM ✅Answered
Hyper-V does not change any of the rules of TCP/IP networking. DNS, gateways, routing, etc. all remain the same within a virtual environment in the same manner that they work in a physical environment.
Generally, the VMs are configured in their own subnet with a gateway to the outside world. This is often the router that has one port connected to the ISP and has the fixed IP address provided by the ISP and another port connected to the subnet of the VMs.
Example: router has ISP address of 72.1.1.200 and subnet of 192.168.2.1. All the VMs are on the 192.168.2.0/24 subnet. VMs point to the Windows Domain Controller for their DNS and 192.168.2.1 as their default gateway. Windows domain controller has a fixed 192.168.2.0/24 IP address is has DNS configured on it. Yes, if you want the VMs to communicate with the internet, you have to have an external virtual switch defined in Hyper-V (does not have to be shared with the host, but it works either way). That physical NIC is the one that is connected to a physical port on the router.
You say you have networking experience. Keep it simple and apply the rules you know from physical networking. ISP - router - VMs. Done this many times with no issues.
tim
Monday, June 17, 2019 1:22 PM
The gateway for all domain members is typically the router address. All domain members should have the static ip address of domain controller listed for DNS and no others such as router or public DNS
Regards, Dave Patrick ....
Microsoft Certified Professional
Microsoft MVP [Windows Server] Datacenter Management
Disclaimer: This posting is provided "AS IS" with no warranties or guarantees, and confers no rights.
Thursday, June 20, 2019 10:42 AM
Hi,
Just want to confirm the current situation.
Please feel free to let me know if you need further assistance.
Best regards,
Michael
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