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How to check and close open ports on Windows using PowerShell or netstat

Last updated on Sep 23,2025 |

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by wynston

Introduction

On Windows systems, applications and services communicate over specific network ports. Sometimes, ports remain open unnecessarily due to misconfigured software, unresponsive processes, or malicious applications. Open ports can create security risks and lead to conflicts with other services trying to use the same port.

Administrators often need to check which processes are using specific ports and, if necessary, close them. For example, if a web server (IIS, Apache, or Nginx) fails to start because port 80 is already in use, identifying and terminating the process holding the port resolves the issue.

Windows provides multiple ways to accomplish this. The two most common are:

netstat (built into Windows, accessible via Command Prompt or PowerShell).
PowerShell cmdlets for process and networking management.

Prerequisites

Windows 7, 8, 10, or 11.
Administrator privileges.
Familiarity with Command Prompt or PowerShell.

Step-by-step Guide

Step 1: Open PowerShell or Command Prompt as Administrator

Press Windows Key + S and type either powershell or cmd.
Right-click the program and select Run as administrator.

Step 2: List Open Ports with netstat

To display active ports and their associated processes, run:

netstat -ano

This shows:

Proto: Protocol (TCP/UDP).
Local Address: IP and port number in use.
PID: Process ID of the program holding the port.

For example:

Proto  Local Address          Foreign Address        State           PID
TCP    0.0.0.0:80             0.0.0.0:0              LISTENING       1234

Step 3: Find Which Application Uses the Port

Once you have the PID, run this command in PowerShell or Command Prompt:

tasklist /fi "PID eq 1234"

Step 4: Close the Port by Terminating the Process

If the process is not required, it can be terminated using:

taskkill /PID 1234 /F

Replace 1234 with the actual PID.

⚠️ Important Note: Only terminate processes if you are certain they are not critical to system operation. Closing the wrong process could cause system instability or service disruption.

Step 5: Alternative – Use PowerShell to Find and Close Ports

You can also use PowerShell cmdlets. For example, to check which process is using port 80:

Get-Process -Id (Get-NetTCPConnection -LocalPort 80).OwningProcess

To stop it:

Conclusion

Checking and closing open ports on Windows is an essential step for troubleshooting service conflicts and improving system security. Using netstat and PowerShell, administrators can quickly identify which processes occupy specific ports and safely terminate them if needed.

This ensures critical applications like web servers, databases, or remote desktop services can function without interference from unnecessary processes.

Should you have any inquiries about the guidelines, please feel free to open a ticket through your portal account or contact us at support@ipserverone.com. We’ll be happy to assist you further.