We have a new HP server, running Server 2012 Standard w/4 nics. 2 nics are disabled, one nic is connected to our local lan, and the other active nic is connected to our ISP only. Both nics have static IP addresses, with the ISP nic the only one having a gateway so all traffic is routed through that nic with the exception of the local lan traffic.
The reason for the above is we have made an image of a live SQL server that we would like to boot up, install all windows updates, and test upgrading to latest version of SQL, etc...
I have created a virtual switch, called it DMZ, and associated it with the nic that is directly connected to the ISP. I have turned off Allow management operating system to share this network adapter. I have also assigned a static IP to this NIC in the VM. From within this VM, I have internet access that is going out through the ISP rather than local lan as verified by tracert. This works and looks good. The only issue we have is, we can still ping internal ip addresses on our local lan. We cannot resolve names, but can ping IP addresses, which is a little scary as we want to completely isolate this from our internal network so we don't foul anything up production wise. We have tried everything from creating false routes, etc... but after failing to ping 1 time, it someone autocorrects itself and finds the route back again. I have scoured everything and cannot find the answer. Any help would be much appreciated.