At any one time, there’s a whole bunch of information being sent between your Windows 10 PC and the endless void of the Internet. This is done using a process whereby network-dependent processes seek out TCP and UDP ports, which they use to communicate with the Internet. First, your data gets sent to remote ports at the destination or website your processes are trying to connect to, then it gets received at local ports back on your PC.
Most of the time, Windows 10 knows how to manage ports and ensure that traffic is being directed through the right ports so that those processes can connect with what they need to. But sometimes two processes may be assigned to one port, or maybe you just want to get a better picture of your network traffic and what’s going in and out.
That’s why wrote this guide that shows you how to check open ports on Windows and see which applications are using which ports.
Also read: How to Set Up Port Forwarding in Windows
Check Port Usage With Nirsoft CurrPorts
NirSoft is one of the best indie software developers, giving us great utilities, like PassView and WirelessKeyView. While some people will prefer checking their ports without installing third-party software (in which case, scroll down to the CMD method), CurrPorts is easily the fastest and most convenient way to check port status on Windows.
Once you’ve installed CurrPorts, just open it to see a list of all your ports currently in use. If you’re looking for local ports in use, just click the “Local Port” column at the top to order the list by port number (handy if you’re looking for a specific one). You can do the same thing with remote ports, too.
If you want to really find specific ports, click the “Advanced Filters” icon at the top and enter your string in the format they suggest. It should look something like the below image.
Hit OK when you’re ready, and the list will filter down to your queries.
Also read: How to Open Ports and Set Up Port Forwarding on Your Router
List Open Ports Using the Command Prompt
The integrated – though not necessarily the simplest – way to check open ports is to use the trusty command prompt.
Click the Start button, type cmd, then right-click “Command Prompt” when it shows up in the search results. Click “Run as administrator.”
Once you’re in the elevated command prompt, enter the following command:
netstat -abThis will steadily bring up a list of open ports that is probably quite long, along with the Windows processes that are using them. (You can press Ctrl + A , then Ctrl + C to copy all information to the clipboard.) On the average PC, there will be two main local IP addresses that contain ports on your PC.
The first, in our case, is “127.0.0.1.” This IP address is otherwise known as “localhost” or a “loopback address,” and any process listening to ports here is communicating internally on your local network without using any network interface. The actual port is the number you see after the colon. (See image below.)
The bulk of your processes will probably be listening to ports prefixed with “192.168.xxx.xxx,” which is your IP address. This means the processes you see listed here are listening for communications from remote Internet locations (such as websites). Again, the port number is the number after the colon.
Also read: How to Disable USB Ports in Windows 10
Install TCPView to Check Open Ports
If you don’t mind installing a third-party app and want to have more control over what’s going on with all your ports, you can use a lightweight app called TCPView. This immediately brings up a list of processes and their associated ports.
What make this better than the command prompt is that you can actively see the ports opening, closing and sending packets. Just look for the green, red and yellow highlights. You can also reorder the list by clicking the column headings, making it easier to find the process you want or two separate processes vying for the same port.
If you do find a process or connection you want to close, just right-click that process. You can then select “End process,” which is exactly the same function as the one in Windows task manager. Or you can click “Close Connection” to leave the process open but stop it from listening on a given port.
If you’re having some trouble in Windows 10, then see whether a Windows update may be causing it. We also have a handy guide for managing the health of your hard drive in Windows 10.
При запуске новых сервисов в Windows, вы можете обнаружить что нужный порт уже занят (слушается) другой программой (процессом). Разберемся, как определить какая программ прослушивает определенный TCP или UDP порт в Windows.
Например, вы не можете запустить сайт IIS на стандартном 80 порту в Windows, т.к. этот порт сейчас занят (при запуске нескольких сайтов в IIS вы можете запускать их на одном или на разных портах). Как найти службу или процесс, который занял этот порт и завершить его?
Чтобы вывести полный список TCP и UDP портов, которые прослушиваются вашим компьютером, выполните команду:
netstat -aon| find "LIST"
Или вы можете сразу указать искомый номер порта:
netstat -aon | findstr ":80" | findstr "LISTENING"
Используемые параметры команды netstat:
- a – показывать сетевые подключения и открытые порты
- o – выводить идентфикатор професса (PID) для каждого подключения
- n – показывать адреса и номера портов в числовом форматер
По выводу данной команды вы можете определить, что 80 порт TCP прослушивается (статус
LISTENING
) процессом с PID 16124.
Вы можете определить исполняемый exe файл процесса с этим PID с помощью Task Manager или с помощью команды:
tasklist /FI "PID eq 16124"
Можно заменить все указанные выше команды одной:
for /f "tokens=5" %a in ('netstat -aon ^| findstr :80') do tasklist /FI "PID eq %a"
С помощью однострочной PowerShell команды можно сразу получить имя процесса, который прослушивает:
- TCP порт:
Get-Process -Id (Get-NetTCPConnection -LocalPort 80).OwningProcess - UDP порт:
Get-Process -Id (Get-NetUDPEndpoint -LocalPort 53).OwningProcess
Можно сразу завершить этот процесс, отправив результаты через pipe в командлет Stop-Process:
Get-Process -Id (Get-NetTCPConnection -LocalPort 80).OwningProcess| Stop-Process
Проверьте, что порт 80 теперь свободен:
Test-NetConnection localhost -port 80
Чтобы быстрой найти путь к исполняемому файлу процесса в Windows, используйте команды:
cd /
dir tiny.exe /s /p
Или можно для поиска файла использовать встроенную команду where :
where /R C:\ tiny
В нашем случае мы нашли, что исполняемый файл
tiny.exe
(легкий HTTP сервер), который слушает 80 порт, находится в каталоге c:\Temp\tinyweb\tinyweb-1-94
Checking open TCP/IP ports on your Windows computer is crucial for managing network security and ensuring smooth connectivity. Certain apps and processes in Windows may face issues due to closed or misconfigured ports, often caused by firewalls or private IP addresses. This guide will walk you through step-by-step methods to check whether a TCP port is open or closed using built-in tools and third-party utilities.
Why You Should Check TCP/IP Ports?
Here are some common scenarios where checking ports is necessary:
- Troubleshooting connectivity issues for applications or services.
- Configuring firewalls to ensure necessary connections are allowed.
- Detecting suspicious activity that might indicate a security breach.
Methods to Check Open TCP/IP Ports
There are several ways to check open TCP/IP ports in Windows. Here are a few options:
Method 1. Using Telnet Client
Step 1: Check whether the telnet client feature is ON or not. In order to check, open the Turn Windows feature on or off settings from the search bar. OR press the ‘window’ key and type ‘windows’ features. Then press on “Turn Windows features on or off”.
-660.png)
Windows Features Option
A new prompt will be opened. Search for “Telnet Client” and check the box in front of ‘telnet Client’.
Windows Features
Step 2: Open the command prompt. Press the ‘windows’ key and type ‘cmd’. Press “Command Prompt”.
-660.png)
Command Prompt Option
Step 3: On the command prompt, type the command “telnet + IP address or hostname + port number” and check the status of the provided TCP port.
-660.png)
Telnet Command
Step 4: If only the blinking cursor is visible, then the port is open.
-660.png)
Port is Open
Step 5: If you get the message “connection failed” then the port is closed.
-660.png)
Port is close
Method 2: Using built-in netstat command-line utility:
Step 1: Open the command prompt.
Step 2: Run the following command:
netstat -an
Method 3. Using TcpView
Another option is to use the TcpView utility from Microsoft’s Sysinternals suite of tools. This utility provides a more user-friendly interface for viewing active TCP/IP connections, along with additional information such as the process ID and process name for each connection. Steps to be followed:
Step 1: Download the TcpView utility from the Microsoft Sysinternals website. You can find the download link on the TcpView page of the Sysinternals website.
-660.png)
Download Page
Step 2: Extract the downloaded file and run the TcpView.exe file to launch the TcpView utility. This will open the TcpView window, which shows a list of all active TCP/IP connections on your machine.
Extracted FIles
Step 3: Open the tcpview.exe (application).
By default, TcpView will display the following columns in the list of connections:
Protocol: Shows the protocol being used for the connection (TCP or UDP)
Local Address: Shows the local address and port being used for the connection
Remote Address: Shows the remote address and port being connected to
State: Shows the current state of the connection (e.g. Established, Listen, etc.)
You can use the “Local Address” and “Remote Address” columns to see which ports are being used by which applications. For example, if you see a connection with a local address of “127.0.0.1:80”, this means that the local application is using port 80 for outgoing connections.
Method 4. Using Windows PowerShell
You can also use Windows PowerShell to check open TCP/IP ports. To do this, use the Get-NetTCPConnection cmdlet, which allows you to view a list of active TCP/IP connections and the local and remote addresses and ports being used. For example, you can run the following command to view a list of all active TCP/IP connections:
Get-NetTCPConnection |
Select-Object LocalAddress,
LocalPort, RemoteAddress, RemotePort
Get-NetTCPConnection cmdlet
Method 5. Using Nmap
To install Nmap in the Windows command line, follow these steps:
Step 1: Download the latest version of Nmap from the Nmap website. You can find the download link on the Nmap download page:
https://nmap.org/download.html
Step 2: Extract the downloaded file to a location on your computer. This will create a new folder containing the Nmap files.
Step 3: Open a command prompt and navigate to the directory where you extracted the Nmap files. For example, if you extracted the files to the C:\nmap directory, you would run the following command:
cd C:\nmap
Step 4: Once you are in the Nmap directory, you can install Nmap by running the nmap.exe file. To do this, run the following command:
nmap.exe -V
This will display the version number of Nmap, indicating that it has been installed successfully.
Step 5: To use nmap to scan for open TCP/IP ports, run the “nmap -sT” command, followed by the IP address or hostname of the machine you want to scan.
nmap -sT localhost
This will scan the specified host or IP address and display the results. You can also use the -h option to view a list of available options and arguments for the nmap command. Overall, installing Nmap in the Windows command line is a straightforward process. You can download the latest version of Nmap from the Nmap website, extract the files, and then run the nmap.exe file to install it. Once it is installed, you can use the nmap command to scan hosts and IP addresses and view the results.
Common Issues That Close Ports
- Applications not functioning as expected.
- Misconfigured firewall rules blocking connections.
- IP addresses improperly set as private.
Troubleshooting Common Issues
Here are some common issues that may occur during opening TCP/IP Ports in Windows:
- Telnet Not Listed in Features: Ensure your system version supports Telnet or enable it via PowerShell.
- Firewall Blocking Ports: Temporarily disable the firewall to test port connectivity.
- Command Not Recognized: Verify tool installation and environment variables.
Conclusion
Checking open TCP/IP ports on your Windows computer is an important step for maintaining your system’s security and efficiency. By regularly monitoring these ports, you can identify any unwanted or suspicious connections that might put your computer at risk. Windows provides several simple tools, like Command Prompt and PowerShell, which make it easy to see which ports are open and what applications are using them. Taking the time to check your open ports helps ensure that your computer runs smoothly and stays protected from potential threats. Staying proactive about monitoring your network connections is a key part of keeping your digital environment safe and reliable.
В Windows при запуске сервисов может возникнуть конфликт портов, если нужный порт уже занят другим процессом. Например, IIS не запустится на порту 80, если он используется. В этой статье расскажем, как определить, какая программа прослушивает TCP или UDP порт, с помощью netstat, PowerShell, tasklist и как освободить порт.
Приобрести оригинальные ключи активации Windows 11 можно у нас в каталоге от 1690 ₽
Поиск программы по порту с помощью netstat
1. Выведите все прослушиваемые порты:
netstat -aon | find "LIST"
Параметры:
– -a: показывает все подключения и порты.
– -o: отображает PID процесса.
– -n: числовой формат адресов и портов.
2. Найдите процесс по конкретному порту (например, 80):
netstat -aon | findstr ":80" | findstr "LISTENING"
Пример вывода: порт 80 занят процессом с PID 16124.
3. Определите программу по PID:
tasklist /FI "PID eq 16124"
Вывод покажет имя исполняемого файла (например, tiny.exe).
4. Однострочная команда:
for /f "tokens=5" %a in ('netstat -aon ^| findstr :80') do tasklist /FI "PID eq %a"
Поиск программы с помощью PowerShell
1. Найдите процесс для TCP-порта:
Get-Process -Id (Get-NetTCPConnection -LocalPort 80).OwningProcess
2. Найдите процесс для UDP-порта:
Get-Process -Id (Get-NetUDPEndpoint -LocalPort 53).OwningProcess
3. Завершите процесс:
Get-Process -Id (Get-NetTCPConnection -LocalPort 80).OwningProcess | Stop-Process
4. Проверьте, свободен ли порт:
Test-NetConnection localhost -Port 80
Поиск пути к исполняемому файлу
1. Поиск файла по имени:
cd \
dir tiny.exe /s /p
2. Использование where:
where /R C:\ tiny
Пример: найдено c:\Temp\tinyweb\tinyweb-1-94\tiny.exe.
Устранение неполадок
Порт не отображается:
– Убедитесь, что процесс запущен (netstat -aon).
– Проверьте права администратора для PowerShell.
Конфликт портов:
– Завершите процесс (Stop-Process) или измените порт сервиса (например, в настройках IIS).
Файл не найден:
– Проверьте правильность имени файла в tasklist.
– Используйте where для поиска по всему диску.
Рекомендации
– Безопасность: Завершайте только известные процессы, чтобы не нарушить работу системы.
– Мониторинг: Используйте Resource Monitor (resmon) для визуального анализа сетевых подключений.
– Автоматизация: Создайте скрипт для проверки портов:
$port = 80
$process = Get-Process -Id (Get-NetTCPConnection -LocalPort $port -ErrorAction SilentlyContinue).OwningProcess
if ($process) { Write-Output "Port $port used by $($process.ProcessName) (PID: $($process.Id))" } else { Write-Output "Port $port is free" }
– Логи: Проверяйте Event Viewer (eventvwr) для анализа ошибок портов.
Определение программы, использующей порт в Windows, возможно через netstat, tasklist или PowerShell (Get-NetTCPConnection, Get-NetUDPEndpoint). Эти инструменты позволяют быстро найти процесс, завершить его или освободить порт. Использование PowerShell упрощает автоматизацию и предоставляет гибкость для анализа сетевых подключений.
Лицензионный ключ активации Windows от
Connections between applications work much like conversations between humans. The conversation is started by someone speaking. If no one is listening, then the conversation doesn’t get far. How do you know who’s listening on a Windows PC? The Netstat command-line utility and the PowerShell Get-NetTCPConnection cmdlet.
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In this tutorial, you will learn how to inspect listening ports and established TCP connections on your Windows computer with Netstat and the native PowerShell command Get-NetTCPConnection.
Prerequisites
If you’d like to follow along with examples in this tutorial, be sure you have:
- A Windows PC. Any version will do. This tutorial is using Windows 10 Build 21343.1
- PowerShell. Both Windows PowerShell and PowerShell 6+ should work. This tutorial us using PowerShell v7.2.0-preview.2
Using Netstat to Find Active and Listening Ports
Netstat is one of those command-line utilities that seems like it’s been around forever. It’s been a reliable command-line utility to inspect local network connections for a long time. Let’s check out how to use it to find listening and established network connections.
Netstat has many different parameters. This tutorial will only use three of them. To learn more about what netstat can do, run
netstat /?.
Assuming you’re on a Windows PC:
1. Open up an elevated command prompt (cmd.exe).
2. Run netstat -a to find all of the listening and established connections on the PC. By default, netstat only returns listening ports. Using the -a parameter tells netstat to return listening and established connections.
The output above is broken out into four columns:
Proto– shows either UDP or TCP to indicate the type of protocol used.Local Address– shows the local IP address and port that is listening. For many services, this will be 0.0.0.0 for the IP part, meaning it is listening on all network interfaces. In some cases, a service will only listen on a single Network Interface (NIC). In that case, netstat will show the IP address of the NIC. A colon separates the IP address from the port that it is listening on.Foreign Address– shows the remote IP address the local connection is communicating with. If theForeign Addressis0.0.0.0:0, the connection is listening for all IPs and all ports. For established connections, the IP of the client machine will be shown.State– shows the state the port is in, usually this will beLISTENINGorESTABLISHED.
3. Now run netstat -an. You should now see that any names in the output have been turned into IP addresses. By default, netstat attempts to resolve many IP addresses to names.
4. Finally, perhaps you’d like to know the Windows processes that are listening or have these connections open. To find that, use the -b switch.
Using the
-bswitch requires an elevated command prompt or PowerShell prompt. You will get the errorThe requested operation requires elevationif you use the-bswitch in a non-elevated prompt.
Using PowerShell to Find Active and Listening Ports
Now that you’ve got a chance to see how the old-school netstat utility shows active and listening ports, let’s see how to do it in PowerShell.
Using PowerShell gives you a lot more control to see just what you want, rather than having to scroll through long lists of output. The Get-NetTCPConnection cmdlet is much more specific than netstat about what you want to see.
This tutorial isn’t going to cover all of the parameters that come with the
Get-NetTCPConnectioncmdlet. If you’re curious, runGet-Help Get-NetTCPConnection -Detailedto discover more examples.
On your Windows PC:
1. Open up a PowerShell console as administrator.
The only reason you need to elevate a PowerShell console is to see the program that owns the connection (like the netstat
-bparameter).
2. Run Get-NetTcpConnection. You’ll see output similar to what netstat provided. Instead of just a big string of output, Get-NetTcpConnection returns a list of PowerShell objects.
You can now see the same general information that netstat provided you by now; by default, you have information on the OwningProcess (the -b switch on netstat) and the AppliedSetting field, which relates to the network profile the connection is a part of.
Unlike netstat, the
Get-NetTCPConnectioncmdlet will now show listening UDP connections.
3. Pipe the output to Select-Object showing all properties. You’ll see PowerShell returns a lot more information that netstat did.
Get-NetTCPConnection | Select-Object -Property *
4. Now, narrow down the output to just listening ports.
Get-NetTCPConnection -State Listen
5. Now, find the process names for the OwningProcess fields. To do that, run the Get-Process cmdlet and provide the process ID as shown below.
If you’d like to create another property for the process name, you could optionally use a Select-Object calculated field.
Get-NetTCPConnection | Select-Object -Property *,@{'Name' = 'ProcessName';'Expression'={(Get-Process -Id $_.OwningProcess).Name}}6. Narrow down the states to a bit more by finding Listening and Established states by defining the State parameter value as a comma-delimited list.
Get-NetTCPConnection -State Listen,Established7. Finally, limit the connections down by the port the connection is connected to with the RemotePort parameter.
Use the
LocalPortparameter to filter connections by local port.Get-NetTCPConnection -RemotePort 443
Get-NetTCPConnection -RemotePort 443
Conclusion
You have now seen how the Netstat utility and the Get-NetTCPConnection PowerShell cmdlet help you find local network connections.
Now that you can show the processes running on a server combine this with the Test-NetConnection PowerShell cmdlet to get an end-to-end view of connectivity between a client and server.