How to open a port in Microsoft Defender Firewall

IMPORTANT!

If using a different firewall, the following instructions may not apply.

The example of port 27027 will be demonstrated, but the same procedure should be applied to all blocked ports.

To open a port in Microsoft Defender Firewall:

On the Start menu, type Run, type WF.msc, and then click OK. 

In the Windows Firewall with Advanced Security, in the left pane, Inbound Rules, and then click New Rule in the action pane. 

In the Rule Type dialog box, select Port, and then click Next. 

Select TCP and Type in 27027 in the specific local port field, then click Next.

Select Allow the connection, and then click Next.

Apply the rule to all 3 options, and click Next.

In the Name dialog box, type the name 3Shape Dongle Server Service and add a description for this rule, and then click Finish.  

Follow the same instructions to create a new rule in Outbound rules.

NOTE: If this does not resolve the issue, a firewall on the network itself may be causing the problem. 

How to check if the port is open with netstat:

To check if a port is open using netstat, follow these steps:

Open Command Prompt:

Press Win + R, type cmd, and press Enter.

In the Command Prompt window, type the following command and press Enter: netstat -an | find "PORT" (replace PORT with the port number you want to check).

Review the Results:

Look for lines that include the port number in the "Local Address" column.

If the port is open and listening, it should appear as 0.0.0.0:PORT or ::PORT with the status “LISTENING.”

Close Command Prompt.

This process helps determine if the port is open and being used by any application on your local machine.