Hyper-V Server virtual machine network connection failure – vm network issues

Hi,

This has been a problem that has haunted me for over 18 months now and finally I have a solution.

The Problem

I have been creating virtual machines and been getting inconsistent success with getting the virtual network card inside the Virtual machine to successfully connect to the network. It will start up with a yellow “Warning” icon showing and when you confirm the IP Addres settings it is an invalid 169.x.x.x address. I am attempting to use DHCP to assign the IP.

I this situtation I have tried the following:

1. netsh int ip reset – followed by a reboot.
2. stop the VM, remove the network card completely, start the VM and login, shutdown the VM, add the network card back, start the vm and login
3. changed the MAC ADDRESS on the virtual card to ensure it is not conflicting on the network.

All of these have failed.

This has been really confusing as I have created 2 Virtual Machines at the same time, from the same sysprep’d .vhd image and one will succeed and one will fail!!!

The only thing that has worked is to assign a static IP address.

Solution

A friendly member of the infrastructure team where I am working fixed it in about 2 seconds.

Apparently due to the way the newtork as been configured we run a virtual Lan, its number so happens to be 100.

So in hyper-v server find this screen:

And change it to something like this:

This sovled my problem.

I don’t know why sometimes it was set correctly and other times not, but this definitely solved my problems.

Let me know if it works for you.