Tuesday, July 19, 2011

Misconfigured Interfaces on NLB cluster of Hyper-V VMs

If you ever attempt to form a Network Load Balancing (NLB) cluster with 2 or more Hyper-V VMs, you would be likely to see errors saying that the interfaces are misconfigured and both cluster and dedicated IP addressess are unable to be added to TCP/IP.

To workaround this issue, shut down the VMs. Open up Hyper-V manager and enable MAC spoofing on the interfaces that you want to load-balance as follows:

Start the VMs. Remove the old cluster and form a new one.


  1. Thank you for the post. This error was driving me nuts.

  2. Cheers. Obvious once you know lol!

  3. Thanks. I was working on my vms and had this problem.

  4. Thanks you so much...