This setting determines the behavior for inbound connections that do not match an inbound firewall rule. The recommended state for this setting is: Block (default) . Fix: (1) GPO: Computer Configuration\Policies\Windows Settings\Security Settings\Windows Firewall with Advanced Security\Windows Firewall with Advanced Security\Windows Firewall Properties\Domain Profile\Inbound connections (2) REG: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile!DefaultInboundAction