I have been working upgrading 40 servers from Windows Server 2008 R2 to Windows Server 2012. The process is fairly straightforward:
- Remotely connect to Server
- Launch the WS2012 setup.exe
- Follow instructions
After starting the upgrade, the servers rebooted and I just waited for them to finish.
About an hour or so, I tried to remotely connect to the server with no luck. I was able to ping them, and after going to the Datacenter, I noticed that it had WS2012 installed and had a valid IP – what gives?
After messing with the Firewall, I noticed that two Remote Desktop rules in the inbound Firewall rules were enabled and one Remote Desktop rule was enabled:
Enabling these rules allowed me to remotely connect again to the servers.
If you do not want to physically access the servers to make this change, you can always open an MMC console and create a Firewall Snap-In connected to the remote computer where you will be able to make these changes.
Additionally, you can enable the following rule before going through the upgrade in WS 2008 R2: