If a Microsoft Windows system is running the
Microsoft Defender
Firewall,
firewall software that comes with Microsoft Windows systems, you can
check on whether connectivity is allowed on a particular
network
port from a
command-line
interface (CLI) using
PowerShell. You can determine whether the Windows Firewall is active on a
system from a command prompt
using the command netsh advfirewall show
currentprofile. If the value of "State" is "ON", then the Windows
Firewall is active on the system.
C:\>netsh advfirewall show currentprofile Domain Profile Settings: ---------------------------------------------------------------------- State ON Firewall Policy BlockInbound,AllowOutbound LocalFirewallRules N/A (GPO-store only) LocalConSecRules N/A (GPO-store only) InboundUserNotification Enable RemoteManagement Disable UnicastResponseToMulticast Enable Logging: LogAllowedConnections Disable LogDroppedConnections Disable FileName %systemroot%\system32\LogFiles\Firewall\pfirewall.log MaxFileSize 4096 Ok. C:\>
You can check on whether the firewall is permitting connectivity on a
particular network port, e.g., TCP port 3389 for the
Remote Desktop
Protocol (RDP), from a PowerShell prompt, which you can obtain by
typing powershell in the Windows "Search" field at the bottom
of the screen and then clicking on Windows PowerShell when you see
it returned by the search function. At the PowerShell prompt, you can issue
the command Get-NetFirewallPortFilter | Where-Object { $_.LocalPort -eq
3389 } | Get-NetFirewallRule. If you wished to check on whether
firewall connectivity is permitted for some other protocol, substitute
the port used by that protocol, e.g., port 22 for
Secure Shell (SSH)
connections.On the Windows 11 system below
on which the command was issued, the firewall is permitting connections on
TCP
port 3389 on the Windows
domain network, but not allowing connectivity for
private or public
networks — if the system was a laptop that may be moved from network
to network, e.g., it might sometimes be on a public
Wi-Fi network, you might
not want to allow connectivity via RDP when the system is connected to
such public networks. In the example below, the setting for
Enabled for the Profile value of "Private, Public" is
"False" while when Profile equals Domain, the value for
Enabled is True. RDP can use both TCP connectivity and
User
Datagram Protocol (UDP) transmissions, but in the example below, incoming
UDP transmissions are not allowed by the firewall; you can see the
value for "Enabled" for incoming UDP transmissions is "False".
PS C:\WINDOWS\system32> Get-NetFirewallPortFilter | >> Where-Object { $_ .LocalPort -eq 3389 } | >> Get-NetFirewallRule Name : {D0A59A70-BBA8-40BA-821F-5D1D7B40D645} DisplayName : Remote Desktop - User Mode (TCP-In) Description : Inbound rule for the Remote Desktop service to allow RDP traffic. [TCP 3389] DisplayGroup : Remote Desktop Group : @FirewallAPI.dll,-28752 Enabled : True Profile : Domain Platform : {} Direction : Inbound Action : Allow EdgeTraversalPolicy : Block LooseSourceMapping : False LocalOnlyMapping : False Owner : PrimaryStatus : OK Status : The rule was parsed successfully from the store. (65536) EnforcementStatus : NotApplicable PolicyStoreSource : PersistentStore PolicyStoreSourceType : Local RemoteDynamicKeywordAddresses : {} PolicyAppId : Name : RemoteDesktop-UserMode-In-TCP DisplayName : Remote Desktop - User Mode (TCP-In) Description : Inbound rule for the Remote Desktop service to allow RDP traffic. [TCP 3389] DisplayGroup : Remote Desktop Group : @FirewallAPI.dll,-28752 Enabled : False Profile : Private, Public Platform : {} Direction : Inbound Action : Allow EdgeTraversalPolicy : Block LooseSourceMapping : False LocalOnlyMapping : False Owner : PrimaryStatus : OK Status : The rule was parsed successfully from the store. (65536) EnforcementStatus : NotApplicable PolicyStoreSource : PersistentStore PolicyStoreSourceType : Local RemoteDynamicKeywordAddresses : {} PolicyAppId : Name : RemoteDesktop-UserMode-In-UDP DisplayName : Remote Desktop - User Mode (UDP-In) Description : Inbound rule for the Remote Desktop service to allow RDP traffic. [UDP 3389] DisplayGroup : Remote Desktop Group : @FirewallAPI.dll,-28752 Enabled : False Profile : Any Platform : {} Direction : Inbound Action : Allow EdgeTraversalPolicy : Block LooseSourceMapping : False LocalOnlyMapping : False Owner : PrimaryStatus : OK Status : The rule was parsed successfully from the store. (65536) EnforcementStatus : NotApplicable PolicyStoreSource : PersistentStore PolicyStoreSourceType : Local RemoteDynamicKeywordAddresses : {} PolicyAppId : PS C:\WINDOWS\system32>
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