Check if a network port is open

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Check if a network port is open
Check if a network port is open
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This article will show you how to check if a specific port is open on your computer or network.

Steps

Method 1 of 5: Checking an external port

Step 1. Go to https://www.canyouseeme.org in your web browser

On this website you can see whether a port on your computer or network is accessible via the internet. The website will automatically detect your IP address and show it in the 'Your IP:' box

There are several websites that allow you to check open ports. Search for 'open port check tool' in a search engine to find an alternative, if you like

Step 2. Fill in the port

Type the number of the port you want to check (for example, 22 for SSH) in the 'Port to Check:' box

Step #3. Click on Check Port

If the gate is open, you will now see a confirmation. If the port is not open, you will get the message 'Error: I could not see your service on (your IP address) on port (port number).'

Method 2 of 5: Check if an app is allowed through the Windows firewall

Step 1. Open Windows Search and type firewall

If the search bar isn't already open, click the circle or magnifying glass to the right of the start menu.

  • Use this method if you want to check if a particular app has permission from the Windows firewall to connect to the internet.
  • The Windows firewall is enabled by default. If you have other firewall software installed, open that program to see if the app is allowed through.

Step 2. Click on Windows Defender Firewall

You will now open the virus and threat protection settings.

Step #3. Click Allow an app through firewall

This is one of the links at the bottom of the window. You will now see a list of apps that are allowed through the firewall.

  • If an app is allowed through the firewall only on a network you've marked as "Private" (such as your home network), there will be a checkmark in the "Private" column.
  • If an app is also allowed through the firewall on a network you've marked as 'Public', there will be a checkmark in the 'Public' column.

Step 4. Let a new app through the firewall

If you don't see your app in the list of allowed apps and services, click the 'Change settings' button in the top right corner and follow these steps:

  • click on Pass a new app at the bottom of.
  • click on To leaf through, select the app, and click To open.
  • click on Network types in the lower left corner, select Private or Public, then click OK.
  • click on Add and then OK to add the app.

Method 3 of 5: Check if an app is allowed through the Mac firewall

Step 1. Click on it

Macapple1
menu and select System Preferences.

The Mac firewall is disabled by default.

Step #2. Click on Security and Privacy

This is the house icon in the top row.

Step 3. Click on the Firewall tab

It's at the top, center of the window.

  • If you see the message "Firewall: Enabled" at the top of the tab, your firewall is enabled.
  • If your firewall is not enabled and you want to enable it, click the lock icon in the lower left corner of the window. Then enter your administrator password and click on 'Enable Firewall'.

Step #4. Click on Firewall Options

You now open the firewall options, including a list of apps that allow or block incoming connections.

  • If there is a green dot and the text 'Allow incoming connections' next to an app or service, the port of this app or service is open.
  • If you see a red dot that says 'Block incoming connections', the port of this app or service is closed.
  • You can change the status of a port by clicking the double arrow next to the current status of the app, and then choosing an option.

Method 4 of 5: Check if a local router port is open (Windows)

Step 1. Enable Telnet for Windows

You can use Telnet to check if a particular port is open in your router or access point. Here's how to enable Telnet:

  • Type windows components in the search bar. If you don't see the search bar, click the circle or magnifying glass to the right of the start menu.
  • click on Enable or disable Windows features.
  • Check the box next to 'Telnet client' and click OK.
  • click on Close when the app has finished installing.

Step #2. Open Command Prompt

This is how you do this:

  • Type cmd in the search bar.
  • click on Command Prompt in the search results.

Step 3. At the command prompt, type ipconfig and press ↵ Enter

You will now see a lot of network information.

Step 4. Write down the router's IP address

This is the address next to 'Default Gateway' in the results.

Step 5. Type telnet in the command prompt and press ↵ Enter

You will now open the Microsoft Telnet prompt.

Step 6. Type open (your router's IP address) (port number)

For example, if you want to check if port 25 is open, and your router's IP address is 10.0.0.1, you should type here: open 10.0.0.1 25.

Step 7. Press ↵ Enter

Telnet will now attempt to connect to the port.

  • If you get a message that says 'Please press Enter' or 'Press any key to continue', then the port is open.
  • If you get a message that says 'Could not open connection', then the port is not open.

Method 5 of 5: Check if a local router port is open (Mac)

Step #1. Open a terminal window

To do this, open Spotlight by clicking the magnifying glass in the top right corner of the screen. Then type terminal and click "Terminal" in the search results.

Use this method to see if a particular port is open in your router or access point

Step 2. Type netstat –nr | grep default in the Terminal and press ⏎ Return

Your router's IP address will now appear next to 'default' at the top of the results.

Step 3. Type nc -vz (your router's IP address) (port)

For example, if you want to check if port 25 is open, and your router's IP address is 10.0.0.1, you should type here: nc -vz 10.0.0.1 25

Step 4. Press ⏎ Return

Here's how to interpret the results:

  • If the port is open, you will see a message that the connection was successful (succeeded).
  • If the port is not open, you will see a message that the connection has been refused (refused) or expired (timed out).

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