Windows Firewall: Remote Desktop block action by local policy

group-policywindows-firewallwindows-server-2012-r2

On a fresh domain-joined Server 2012 R2 install I see a peculiarity where an enabled "Remote Desktop" rule is set to Block in the Domain profile:

firewall.cpl screenshot

As block rules take precedence over allow rules, I seem unable to effectively insert a firewall exception allowing RDP traffic to this machine. I cannot edit this rule as "This rule has been applied by the system administrator and cannot be modified". I also cannot override it by the "Remote Desktop" predefined rule in a Group Policy as this does not update the "Remote Desktop" rule but is introducing a new "Remote Desktop (TCP-In)" rule, with the "Remote Desktop" block rule still in place and taking precedence.

Contrary to what the Rule Source column (the first column in the screenshot above) is telling me, the rule is not defined in the machine's local policy:

enter image description here

Folks seem to have encountered this problem on older (Windows 7 / 2008 R2) installs as well, yet there seems to be no effective resolution documented in these cases.

So where does this come from and how to disable this block rule?

Best Answer

I had the same issue and found it was due to a space in the GPO comma delimited list. I documented this on my blog:

TLDR: Don’t put any spaces in the IP address list for the GPO setting for Computer/Admin Templates/Network/Network Connections/Windows Firewall/Domain Profile/Windows Firewall: Allow inbound Remote Desktop exceptions.