How to Check Open Ports in Windows (Full Guide for 2026)

Whether you're troubleshooting network issues, securing a Windows server, or configuring your firewall, knowing how to check open ports in Windows is essential. Open ports can reveal services listening for connections and could indicate potential vulnerabilities if left unmanaged. In this guide, we'll walk you through everything from using CMD, PowerShell, and Task Manager to third-party tools like Nmap, helping you monitor and list all open ports in Windows 10, 11, and Server editions. If you're new to server management, start with our guide on Windows Server administration for the bigger picture.

If you need the fast version, use netstat -ano in Command Prompt, Get-NetTCPConnection in PowerShell, or open Resource Monitor for a GUI view. Those three methods cover most real-world cases, from checking port 443 on a web server to figuring out why port 8080 is already taken. I've tested the commands in this guide on Windows 11 and Windows Server 2022, and the same core workflow also applies to Windows 10, Server 2016, and Server 2019.

For a quick GUI path, press Start, type Resource Monitor, open it, then go to Network > Listening Ports.

If you're working on a server, especially a VPS, you may also want related reading on how to use Nmap and practical VPS security. Those matter once you've confirmed a port is exposed.

What Are Open Ports and Why Should You Check Them?

In the context of computer networks, open ports in Windows refer to communication endpoints that allow inbound or outbound connections to services running on your system. Each port is assigned a number and a specific protocol (TCP or UDP), and it's tied to a service or application. For example:

• Port 80 (HTTP): Used by web servers to serve unencrypted web pages.

• Port 443 (HTTPS): Commonly used for secure web communication.

• Port 3389 (RDP): Allows remote access to a Windows machine using Remote Desktop Protocol.

While many of these ports are necessary for your system or server to function properly—especially on platforms like Windows VPS—they can become entry points for malicious activity if not monitored regularly. Attackers often scan systems for open ports to identify potential vulnerabilities. An unused but open port might be exploited to gain unauthorized access or disrupt services.

So what does "open" actually mean? In plain English, it usually means a service is available on that port and can accept traffic. But you'll see a few different states, and they don't all mean the same thing.

Open vs listening vs closed vs filtered ports

Listening means a local service has bound to the port and is waiting for connections. In Windows command output, this is the state you'll usually care about first.

Open often means the port is reachable and a service responds. Locally listening is one clue, but not the whole story. A port can be listening on localhost and still be blocked remotely by Windows Defender Firewall, NAT, or antivirus.

Closed means nothing is accepting connections on that port. The system may respond with a reset or simply show no service bound there.

Filtered usually means a firewall or security device is dropping traffic, so the scanner can't tell for sure if the service behind it is available. Nmap reports this well. Native Windows tools don't always make the distinction obvious.

And yes, TCP and UDP behave differently. TCP usually shows clear states like LISTENING or ESTABLISHED. UDP is connectionless, so you won't see a TCP-style listening state in the same way.

This is particularly important if you're managing a Windows VPS, where open ports could impact both performance and security. Regularly checking and controlling open ports helps ensure only trusted services are accessible. For a deeper dive into specific port risks, read about what Windows TCP port 135 is and why it's often targeted.

Common Windows ports: 80, 443, 3389, 8080

How to Check Open Ports in Windows Command Line

The most direct way to check open ports in Windows is via the Command Prompt (CMD). Here's how to do it:

Run netstat -ano

In the command prompt window, type:

netstat -ano

This command shows active connections and listening ports, along with the PID, or process ID, of the owning process.

Here's how to read the output:

• Proto: TCP or UDP
• Local Address: the local IP and local port, such as 0.0.0.0:443 or 127.0.0.1:8080
• Foreign Address: the remote IP and remote port
• State: for TCP, you may see LISTENING, ESTABLISHED, TIME_WAIT, and more
• PID: the process ID using that socket

If the Local Address is 0.0.0.0:443, the service is listening on all IPv4 interfaces. If it's 127.0.0.1:443, it's bound only to localhost, which means remote users won't reach it. That's a common gotcha.

Show listening ports only

netstat -ano | findstr LISTENING

This trims the noise and shows only TCP listening ports. It's one of the easiest ways to check listening ports in Windows when you don't care about established sessions.

Check a specific port like 80, 443, 3389, or 8080

netstat -ano | findstr :80

netstat -ano | findstr :443

netstat -ano | findstr :3389

netstat -ano | findstr :8080

This is the quickest way to check if a port is in use in Windows. If you see output for the port, something is bound or connected there. If you see LISTENING, a service is actively waiting on it.

Want more detail, including the executable name? Try this from an elevated Command Prompt:

netstat -abno

How to Check Which Process Is Using a Port in Windows

This is one of the most useful checks on the page. And honestly, it's the section many people were looking for all along.

Find the PID with netstat -aon | findstr

netstat -aon | findstr :443

Look at the last column. That's the PID.

Match the PID in Task Manager

Open Task Manager, go to the Details tab, and look for the matching PID. If you don't see the PID column, right-click the header row and enable it.

Use tasklist to identify the process

tasklist /FI "PID eq 1248"

Replace 1248 with your actual process ID. You'll get the image name for the owning process, which makes it much easier to diagnose conflicts.

How to Check Open Ports in Windows Using PowerShell

PowerShell is my preferred option on modern Windows servers. It gives you structured output, filters better than old text parsing, and is much nicer when you need to export results for auditing. If you're not sure which version you're running, here's how to check your PowerShell version.

List listening TCP ports

Get-NetTCPConnection | Where-Object {$_.State -eq "Listen"}

This lists listening TCP ports only. It's the PowerShell equivalent of checking listening ports in Windows with netstat.

Check a specific port

Get-NetTCPConnection -LocalPort 3389

Get-NetTCPConnection -LocalPort 443

Get-NetTCPConnection -LocalPort 8080

Find the owning process

Get-NetTCPConnection -LocalPort 443 | Select-Object LocalAddress,LocalPort,State,OwningProcess

Get-Process -Id 1248

Check UDP ports with PowerShell

Get-NetUDPEndpoint

Get-NetUDPEndpoint | Select-Object LocalAddress,LocalPort,OwningProcess

This shows bound UDP ports in Windows. If you're checking DNS on port 53 or another UDP-based service, this is usually the cleanest built-in method.

How to Check Open Ports in Windows Using Resource Monitor

For those who prefer a GUI-based method, Resource Monitor is perfectly fine. I still use it when I want a quick visual list of listening ports and the image name beside them.

Open the Listening Ports panel

Press Start, type Resource Monitor, and open it. Then go to Network > Listening Ports.

You'll see the process image, PID, address, port, protocol, and firewall status. For a lot of people, that's easier than reading raw sockets output.

How to Check All Open Ports in Windows with CurrPorts or TCPView

Native Windows tools are enough most of the time. But when you're troubleshooting lots of sockets, or want live updates without running commands over and over, third-party GUI tools help.

CurrPorts vs TCPView

How to Check All Open Ports in Windows Server 2016/2019/2022

On Windows Server, the commands are basically the same. The difference is context: you're usually checking services that matter to uptime, access, or exposure to the internet. If you're planning a fresh deployment, review Windows Server installation basics first.

Best commands for server admins

netstat -ano | findstr LISTENING

Get-NetTCPConnection | Where-Object {$_.State -eq "Listen"}

Get-NetUDPEndpoint

How to verify RDP port 3389

netstat -ano | findstr :3389

Get-NetTCPConnection -LocalPort 3389

If nothing is listening on 3389, Remote Desktop may be disabled, the RDP service may be down, or the port may have been changed. If you need to enable it first, here's how to enable RDP on Windows.

How to export results for audits

netstat -ano > C:\Temp\open-ports.txt

Get-NetTCPConnection | Export-Csv -Path C:\Temp\tcp-connections.csv -NoTypeInformation

Get-NetUDPEndpoint | Export-Csv -Path C:\Temp\udp-endpoints.csv -NoTypeInformation

How to Check If a Port Is Open on a Remote Server

Use Test-NetConnection

Test-NetConnection -ComputerName 192.168.1.10 -Port 443

Test-NetConnection -ComputerName yourserver.example.com -Port 3389

Use Telnet

telnet yourserver.example.com 443

Use Nmap for deeper scans

nmap -p 80,443,3389,8080 yourserver.example.com

How to Check UDP Ports in Windows

Using netstat -ano -p udp

netstat -ano -p udp

This lists UDP endpoints and their owning PIDs.

Using PowerShell

Get-NetUDPEndpoint

Get-NetUDPEndpoint | Where-Object {$_.LocalPort -eq 53}

Why UDP results look different from TCP

TCP is connection-oriented, so the OS tracks states like LISTENING and ESTABLISHED. UDP is connectionless. A service can bind to a UDP port and receive packets without ever showing that same state language.

How to Check If a Port Is Blocked by Windows Firewall

Review inbound rules

Open Windows Defender Firewall with Advanced Security and click Inbound Rules. Look for rules that allow or block the port or the application tied to that port.

Review outbound rules

Outbound rules matter less for hosting inbound services, but they still matter in locked-down environments. Check Outbound Rules if an app needs to initiate connections out.

Listening locally but blocked remotely

If netstat or PowerShell shows the service listening, but Test-NetConnection from another machine fails, check these in order:

• Windows Defender Firewall inbound rule
• Third-party antivirus or endpoint protection
• Cloud firewall or VPS provider security group
• NAT or port forwarding on the edge router
• Whether the service is bound only to localhost

How to Open or Close a Port in Windows Firewall

Allow a port

In Windows Defender Firewall with Advanced Security, create a new inbound rule, choose Port, select TCP or UDP, enter the port number, and allow the connection.

Block or remove a rule

To close an exposed port, disable or delete the inbound rule that allows it. You may also need to stop or reconfigure the service that's listening.

Security best practices

Only allow the ports you actually need. Restrict RDP 3389 by source IP when possible. Disable services you don't use. Audit exposed ports regularly. For dedicated environments, also see security tips for dedicated Windows servers.

Troubleshooting: Why a Port Doesn't Show as Open

The service is not running

If nothing is listening on the expected port, check whether the service actually started. A stopped IIS site, failed application pool, crashed Java app, or disabled RDP service will leave the port closed.

The port is already in use

If your app won't start, another process may already own the port. Use:

netstat -aon | findstr :80

tasklist /FI "PID eq 1234"

Firewall, antivirus, or NAT is blocking access

A local listening port is not proof of remote reachability. Windows Defender Firewall, third-party security tools, cloud ACLs, and routers can all block traffic.

You need admin privileges

Some commands and views need elevation, especially netstat -b and some process lookups. If the output looks incomplete, rerun Command Prompt or PowerShell as Administrator. Also, on a hosted system, provider-side networking can matter. If you're troubleshooting public access on a VPS or dedicated machine, it's worth checking your broader server management setup and any port forwarding or networking rules.

Netstat vs PowerShell vs Resource Monitor vs Nmap

You've got about four methods that really matter here. All of them work. But they don't solve the exact same problem.

Why It's Important to Monitor Open Ports

You may ask: "Why should I spend time checking which ports are open?" The answer lies in the three major benefits of monitoring open ports in Windows—security, troubleshooting, and optimization.

1. Security: Prevent Unauthorized Access

Each open port on your system is like a door into your digital environment. If it's unlocked and unguarded, it's an opportunity for a hacker to exploit. Malware, ransomware, and botnets often exploit open ports to infiltrate systems, especially in unpatched or misconfigured setups.

2. Troubleshooting: Identify and Resolve Network Issues

Open ports are directly tied to running services. If a service isn't working properly—like a website failing to load or a remote desktop connection timing out—it could be due to a blocked or closed port. By auditing open ports, you can identify port conflicts between applications, ensure critical ports are open and reachable, and verify firewall rules are correctly configured.

3. Optimization: Reduce the Attack Surface

Most users and even some administrators leave ports open by default after installing certain software or enabling services. Over time, this results in unused or forgotten ports remaining accessible. Closing these unused ports can improve system performance, strengthen security, and simplify firewall and network configurations.

How to Check Whether Port is Open or Not in Linux?

Although this article primarily focuses on how to check open ports in Windows TCP, it's useful to understand how the process works in Linux as well—especially for users managing hybrid environments or transitioning between systems.

1. Using ss (Socket Statistics)

ss -tuln

2. Using netstat

netstat -tuln

These commands are often used during Linux server audits, troubleshooting, or security hardening processes. For the full Linux walkthrough, see this guide on how to check open ports in Linux. It's useful if you're comparing Windows and Linux server behavior side by side.

Final Thoughts

If you just want the shortest path, start with netstat -ano. If you want cleaner filtering and exports, use PowerShell. If you want to know whether the port is reachable from outside the machine, use Test-NetConnection or Nmap.

And don't stop at finding open ports. Review whether they should be open at all. That's the part many people skip, and it's usually the part that matters most.

If you're running public services on a VPS or Windows Server, keep your firewall rules tight, reduce unnecessary exposure, and audit ports on a schedule. That simple habit catches a surprising amount of mess before it becomes a security incident. For full control over your port configuration and firewall rules, a Windows VPS gives you the isolation and admin access you need.

Summary: Mastering Port Monitoring in Windows

By now, you should be confident in how to check open ports in Windows server 2019 using different methods whether it's CMD, PowerShell, GUI tools, or even advanced scanners like Nmap. Knowing what ports are open helps you maintain system security, troubleshoot applications, and optimize performance.

✅ Whether you're using Windows 10, 11, or any Server edition, monitoring ports is a best practice for every system admin or power user.

🛡️ Want a secure and high-performing environment? Choose a Windows 11 VPS or Windows 10 VPS for desktop flexibility, or a Windows dedicated server for maximum performance and full hardware control.