Use this outbound rule to block IP protocol number 41. Use this outbound rule to blockIP protocol number 41. Fix: (1) GPO: Computer Configuration\Windows Settings\Security Settings\Windows Firewall with Advanced Security\Windows Firewall with Advanced Security\Outbound Rules!Windows Firewall: Block IP protocol number 41 (2) REG: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\WindowsFirewall\FirewallRules!{7337B9B9-2826-419F-A33D-EEB036B51091}