Working for a small company, as well as having a small but extensive personal network (70+ machines), Hyper-V Server 2008 R2 has been my preferred virtualization solution. However, using this free product requires intimately familiarizing oneself with the Server Core environment (aka non-GUI Windows). Anyone who’s been involved with this industry for an extended period of time, or who has always felt comfortable at the Linux command line, will be reasonably familiar with command prompt admin. But troubleshooting and fixing long-standing anomalies with Windows products and the networking configuration information buried within the registry can be especially challenging without the use of GUI tools that can rapidly expose configuration problems. This article will attempt to pull together all the information scattered around the Internet that is vital if fixing, rather than re-loading, Hyper-V Server 2008 R2 is your desired approach. In fact, even completely reloading Hyper-V Server will not necessarily fix guest VM networking anomalies, so you may still find information below useful even if you typically resort to inserting an installation CD at the first sign of inexplicable problems.

Much of this information is available in the invaluable tome published on the IT Core Blog. My goal here is to provide a slightly more concise cookie-cutter toolset and methodology for fixing issues with networking configuration challenges in a dynamic Hyper-V Server environment. If, like me back when I first started with Hyper-V Server, you carefully build your server and VMs without flailing about with different hardware and networking configuration changes, you’ll have been thankfully shielded from the nightmares addressed by the post mentioned above. But if you’ve ever added or changed NICs in your Hyper-V Server environment, both for the host and/or the guests, especially if any such changes affected NICs with statically assigned IP addresses, no doubt you’ve encountered some of the hair-pulling brick walls exemplified by that helpful error message, “Error Applying New Virtual Network Changes.” For such unfortunate souls who have struggled to cure the source of such symptoms, I provide the following painfully learned insights.

To be continued….