Forum Discussion

Bala Sundaram's avatar
Bala Sundaram
Brass Contributor
Sep 24, 2018

Hyper-V Default switch IP address range change. Ver 1809 Build 17763.1

Can one confirm IP address range changed to 192.168.X.Y Subnet 255.255.255.240 from 172.X.X.X   Also changes the subnet randomly on every Hyper-V services startup. 192.168.X.Y . X can change from 5...
kazuo_yamauchi's avatar
kazuo_yamauchi
Brass Contributor
Dec 17, 2018
17763.194 has same issue.
 
According to the Microsoft-Windows-Hyper-V-VmSwitch/Operations log, it shows that the Default Switch is recreated each time the machine is booted.
(When started in safe mode with networking, it is not recreated, so it remains on the same subnet as last normal boot.)
cbj4074's avatar
cbj4074
Brass Contributor
Dec 30, 2018

And that's precisely why this behavior is so annoying.

 

Even though I'm hard-coding a static IP in the VM during provisioning (based upon the dynamic IP that Hyper-V assigns via the Default Switch), as soon as I restart the host machine, the IP address class/range may very well change, which makes the VM network configuration inoperable.

 

To be clear, hard-coding a static IP in the VM is not a problem, as long as the Default Switch in Hyper-V doesn't change the IP address class. But when the guest IP address's first three octets are changing on every host machine reboot, there is simply no reliable means by which to configure a guest VM to use a static IP address. Assigning a static IP during provisioning is a trivial matter in every other virtualization solution! The fact that it's impossible in Hyper-V is bewildering.

 

Is anybody aware of an official "issue" / "bug report" that documents the behavior we're discussing in this thread?