What is Port Forwarding?

If you are not a networking expert, there are some basic concepts that you should understand before you can fully understand the concept of port forwarding . Do not worry, I’ll explain everything simply and quickly!

Before diving into port forwarding, I want to answer some of the questions you might ask.

The port forwarding is a method to make it accessible to computers on the Internet a computer on the private network (such as your computer), even if you are behind a router.

It is commonly used to host video game servers, peer to peer downloads and VOIP applications, voice over IP. There are many other reasons for port forwarding, these are just a few examples.

What is a door?

The ports are virtual paths on which information is transferred over the Internet. There are 65,536 ports to choose from. A good analogy is to think of doors as well as many telephone lines.

What are the commonly Used Ports?

Every program installed on your computer that uses the internet is programmed to send its packages through specific ports. Sometimes the ports are arbitrarily selected by the software programmers, but other times the programmers use a standard port depending on the functionality of the software. Here are some examples of standard door uses:

HTML pages: port 80
FTP file transfer: port 21
POP3 e-mail: port 110
MSN Messenger: port 6901 and ports 6891-6900
For more information on ports that use specific programs, see our PORT FORWARDING port list . You’ll find the ports you need to forward for any application, including Minecraft and uTorrent.
Now that you have a basic knowledge, let’s clarify the concepts well!
Every device on the Internet has at least one IP address.
Each IP address is associated with many ports. When a computer sends data to another computer, it sends it from a port of an IP address to a port of an 192.168.l.254 IP address.
A port can only be used by one program at a time.

With these simple, clear concepts, let’s talk about NAT now . NAT, or Network Address Translation, is a technology that allows each device in the internal network to have its own IP address. While each device in the internal network has its own IP address, from the outside, every request from all these devices seems to come from the same visible IP address publicly assigned by the ISP.

Let’s say you want to open the first page of our site on your PC. For example, when you click on this link to our site, 19216811.info , the request does not go directly to the Internet. Instead, the request goes to your router, which takes note of which internal device is requesting the information, your PC; then the router sends the request to the Internet. When my web server responds (ie the server where this website is present), your router will know exactly which internal device to pass the answer to, ie your PC.

It works exactly the same in reverse! When a computer on the Internet requires, for example, a web page from the IP address, the router must understand which internal device is a web server so that it can fill the request. NAT can handle these requests under certain circumstances. For the rest, you need to know port forwarding .

Fortunately, you already have almost all the information you need. What happens if the router does not know on which internal device a web server is running? All you have to do is say: « Router, send all requests for web pages to my server ». This is what you should say if this were Star Trek, but we are not there yet, so for now you have to access the configuration page of your router and indicate which services are running on which internal devices.

For example … Do you have an FTP server running on an internal computer with an IP address of ?

Configure your router to forward all requests entering port 21 to .

Do you need your internal web server to be accessible to the public? Configure the port forward on port 80.

Of course, you can get complicated if you want, but for the most part it’s just that easy.


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