How to test port forwarding?

So, why would you want to implement test port forwarding? Port mapping/ port forwarding permits a remote computer to connect to a particular service or a computer using a private network. This way, you can run a game server, web server, or a specific service of your choice from the background of the router. In a standard network, the routers run on a public IP address. Servers/ computers can only access a private IP address from a router that is only addressable within the network. Forwarding/ mapping a particular port on your router means directing the traffic from a specific port.

How to test port forwarding
How to test port forwarding? | Image by Gerd Altmann from Pixabay

You will need to verify the success of your port mapping process, and that is why we have this utility on how you can go about it.

How many types of test port mapping are available?

Generally, there are two types of port mapping tests you can perform. The first involves testing the state in which a particular network port is either open or closed. Besides, it tests the presence of responses on the end of the ports. The second involves checking any of the shared port that is open on your private IP address. What is required to perform the test port forwarding?

  • An updated web browser such as Chrome, Firefox, or Safari
  • A Router or computer/ Modem with activated firewall software.


Below are simple high-level steps you can follow when implementing your port forwarding tests. Start by opening the port you intend to test. We assure you have already enabled port forwarding.

  1. Test the port mapping using the internet.

  • Test a single port using the Web Method.

You must know your Internet IP address when using this method. A specific Internet IP address is Remember, the Internet IP address is not the same as your computer IP address, so you must be very keen on this; otherwise, expect to avoid a response.

Use any of the following listed sites to test your single port mapping. You are also required to recognize the exact port number you have already opened so that you can enter its number into the appropriate port number field. You can also key in your IP address if required.

  • ¬†our own site.
  • ¬†
  • ¬†

For instance, when using our own open port tool, enter the port number you want to test, and the site will detect your IP address automatically. This could be ;

IP address:

Port to Check: 80

Check port

Note some of the frequently blocked residential ISP ports include port 25 and port 80 as a precaution of compacting spams and viruses, respectively. Port 80 is the primary port for HTTP connection. If it has been blocked, you will have to run your web server on an unstandardized port. Similarly, port 25 is the primary port for receiving and sending mail. ISPs often block this port as a way of minimizing spams arising from worms on infected machines.

  1. Test a single port using the Telnet method.

Although telnet is an effective method to test port forwarding, it is still not very popular with many people. To perform this method, you are required to run the procedure outside your network. This means that you must be very keen while running it since sometimes the network’s firewall can block the port you want to test. For instance, if you’re using your laptop, the best way is to connect it to your smartphone’s Wi-Fi hotspot. Ensure that there are no other network connections enabled.

A simple telnet test notation will appear like this.

telnet <IP ADDRESS> Port. This means that in Linux or Windows, you can key in telnet 110

Note that is the IP address while 110 is the port number you are trying to test. Other standard Ports you can test include but not limited to

  • FTP 21
  • SSH 22
  • Telnet 23
  • SMTP 25
  • DNS 53
  • HTTP 80
  • POP3 110
  • IMAP 143


If your connection is declined, it simply means that the port you are trying to test is already blocked.

If the connection response is ‘Trying’ for more than five minutes, it simply means an open port, but something is running behind it.

When the connection response is ‘Connected to’ and other similar reactions, it means an open port and service are running behind it.

Press Enter several times or CTRL-C to exit.

  1. Scan for all open ports.

To scan for all open ports (these are ports within a given range), you will be required to do the above procedure only to visit these sites instead. Don’t forget your IP address is

  • (Nmap scan)
  1. You can also test port forward by following these simple steps.

  • 1Type CMD in the search bar of your PC so that a Command Prompt page pops up.
  • 2 Key in telnet, your router WAN IP, port number, and then press the Enter button to run the command entered.
  • 3. A black window should pop up if your port has been successfully forwarded.
  1. Other methods to test port forwarding include;

Besides the online tools, you can also install some specialized software to enable you to scan your network from a different location. You can implement this using tools such as the OpenVAS. This software also performs a 100% security check-up. It is the simplest method for checking open ports.

Why is the security of your connection a concern during test port forwarding?

Your security is of great concern with all things you do on the internet. Depending on the level of your internet security concern, there are several security levels you could get worried about when performing test port mapping.

  1. Universal Plug & Play. UPnP is an excellent security concern whenever you test port forwarding. This provision is designed to automatically set up all port forwarding rules in your computer or router, making it easy to perform test port mapping. However, the real significant threat with this type of port forwarding setup is that it doesn’t include any approval process, which means that any software you downloaded or someone else downloads can practically run your internet connection uncontrolled. To be on the safe side, I recommend you disable the UPnP provision on your computer or router and set it up manually. This is the precaution of restricting unauthorized access into your internet by malice programs and virus which can otherwise corrupt your programs. You are sure that the ports you open are under your management and control, which means that your internet connection security will not be compromised.
  2. Ensure you have decent firewall software. It can be in your modem software if your modem is connected directly to your computer, although these are the low-quality firewall software you can ever come across. The best option is to have a router, typically a distinct piece of hardware connected over your Wi-Fi or Ethernet. The main advantage of such specialized hardware devices is that they will secure your entire network instead of the only computer you will be using.


Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.