How to OPEN ports on your router. EJ: Huawei

The opening, redirection or “mapping” of ports, port mapping O port fordwarding in English, it is a procedure that allows access to a computer on your network (let’s call it a target computer) from the Internet through a specific “channel” or port, for various purposes: remote control, viewing surveillance cameras (2) or being able to play games online with other players (for example, when they do not find you in games).

The barrier that exists and “prevents” access to the computers on your network is your router. Therefore, port forwarding is a configuration that is done there. As there are countless models, I will try to make a tutorial as generalized as possible based on my router, the Huawei HG8546M, so that you have an idea of ​​the procedure. Then you can go to portforward.com, where you will surely find the exact procedure for your router or modem model.

Router access data

The first thing you will need is the access data to your router, IP address, username and password. If you or your internet provider did not change them, you will probably be served the factory settings, which are usually on the label attached to the back of the equipment. In my case, that data is 192.168.100.1, root, adminHW.

Now, in the web browser of any device connected to the router by cable or wirelessly, you must enter the IP of your router in the address bar. A page will be displayed, where you must enter the username and password and click on «Login».

The default IP of the router is generally not changed, so when you enter it in the browser you should see a login screen similar to the illustration. However, the default username and password may be incorrect. In that case, it is quite likely that your Internet provider has changed this information. You should contact them to inform you about it.

Fixed IP

As port forwarding consists of creating a “connection tunnel” from the Internet to the target computer within your network, this computer must have a fixed identifier: specifically a fixed IP address. Considering that routers are usually configured to assign random IPs to computers on the network (DHCP), before doing port mapping you must first assign a fixed IP to that computer.

Likewise, this configuration varies from one router model to another. In my case, the fixed IP option is under the tab «LAN» (Local Area Network), DHCP Static IP Configuration. As shown in the illustration above, I just have to click “New” to add a new configuration. You will have to enter the IP address that you want to assign to the target computer, which will be similar to that of the router, except for the last figure. For example, in my case the IP of my router is 192.168.100.1. The IP of my target machine can be 192.168.100.2. If there is already another computer on the network with this IP, I can change the 2 to any other number that is between 3 and 255.

In addition to the IP, you will also need to enter the MAC address of the target computer. If it’s an Android device, finding its MAC is easy. If it is a Windows PC, press the Windows + R keys. In the window that appears, type cmd and press Enter. At the command line enter ipconfig / all. Your MAC will be on the line that says “Physical Address.” If you have several “network adapters” (for example, if there are virtual machines installed) you should look at the adapter that says “Ethernet” or “Wireless”.

Port opening

In the router configuration screen you will need to look for the port forwarding option. The most common name for this setting is usually Port Mapping or Port Forwarding. In my case it is called Port Mapping Configuration, which can be found under the «Forward Rules«.

In this screen, tap on the «New» option to add a port forwarding. You will have to fill in several fields, starting with the Internal Host, which must be the fixed IP that you should have previously assigned to the target computer. On Protocol you must choose TCP, UDP or both and enter the port number or range of ports (you must enter the same for both the “Internal” Port and the “External” Port fields). These values ​​will already depend on what the creator of the program or game that requires the opening of ports tells you. The rest of the data should be left as it is, be it blank or by default.

Alternative method

In the router’s configuration screen, you must find and activate the UPNP option. In the case of my router, the option is called UPnP Configuration, under the tab Network Application.

Then go to Windows Explorer (you can open any folder), in the left navigation panel tap on the “Network” tab. Your router should appear. Right click on it, Properties, Settings. Click on “Add” and you will be able to Add a port forwarding in a similar way to the previous one. Click on “Accept” in all windows to save the change.

Some users have claimed that with this method they have achieved a successful port forwarding. However, in my case I have seen that this configuration is temporary and disappears after restarting the router.

How to check if a port is open

exist online pages where they tell you that you only have to enter the port number so that it informs you if it is open or not. However, this is not enough. For the test to be successful, the target computer must be “listening” for requests on that port. If not, you will surely see that the port is blocked, despite having opened it in the router.

A simple way to force a Windows PC to listen on a specific port is the portable and lightweight program Port Listener, from the developer RJL Software. You run it, enter the port you want the program to listen on and press “Start”. It is likely that a Windows Firewall window will appear, which you must “Accept” to give the program permission to establish a link with the outside world.

Only after listening to Port Listener, enter any of the online pages to test open ports (I usually use yougetsignal.com for TCP ports and ipvoid.com for UDP ports), enter the port you are testing and click on «Check». You should see something similar to the illustration above: «Port 1234 is open on 123.123.123.123″

My port is still closed

Before explaining the causes of this, you must first be completely sure that you have forwarded the port or ports correctly on your router. This tutorial may not be enough for this, since it is quite general, so you should review a correct tutorial on how to do it on your particular router model.

Firewall

Some devices, such as Windows PCs, incorporate their own barrier or Firewall that is responsible for preventing unauthorized incoming connections from the Internet. Normally the programs and games you install should configure authorization rules in the Firewall during the installation process, so that they do not prevent incoming connections to function properly. However, if this is not the case or you are not sure, you can temporarily disable the Firewall and test if you have a successful connection through the open port. If so, you can manually create the necessary access rule in the Firewall, so that you should not have it completely disabled.

Double NAT

What is Double NAT: Source: Ubisoft

The most likely cause that the ports you have opened on the router appear closed, despite having tested them correctly as I indicated above, is that you are under a Double NAT Internet service. This simply means that you are not directly connected to the Internet, but there is a second router up front (“Second Router” in the illustration). In other words, even if you have opened ports on your router, this second router will be working as an additional “wall”, which is why they cannot see you from the Internet through the port you opened.

To find out if you have an Internet service with Double NAT, you must go to the configuration of your router and look for an option similar to “WAN Information”. Click on the Internet connection that appears (if it is the case) and check that the IP address in the “IP Address” field matches the IP address that they show you online pages like these. If the IP no is the same, so you have a double NAT connection. If it is the same, then luckily you have a simple NAT or public IP, which I will mention later.

The solution to Double NAT would be to carry out a procedure similar to that indicated, but this time considering the two routers. That is, in the second router, the port redirection should point to the IP of your router. However, that second router is surely under the control of your Internet provider or ISP, which is why you will have to arrange with their technical service to carry out this procedure.

Public IP

The other solution to double NAT is to request a public IP from your Internet provider. This change turns your double NAT into single or single NAT. In other words, the second router that I mentioned “disappears”, so that your router connects directly to the Internet and there are no more barriers in between that prevent “seeing” or “listening” through the redirected ports.

The disadvantage of public IP is that it usually has an additional monthly cost to what you already pay for Internet service. For example, in Ecuador some ISPs charge 5 and another 10 dollars. This is a relatively good price compared to other ISPs that only assign you a public IP if you buy a corporate plan, which usually costs double or triple that of a domestic plan.

References: Wikipedia, Ubisoft, Netgear

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