Port Forwarding or port mapping is a technique that is widely used to redirect computer traffic through selected ports between LAN computers (Local network), and remote computers (Internet).
In short, it is a process that allows you to send your network traffic through a port number of your choice and make it accessible for others on the local network or the Internet.
Usually, a VPN or proxy program is used to make this redirection. Still, it can also be done via hardware components such as a router, proxy server, or a firewall.
Learn about What is Port Number?
Port Mapping, exists in several forms. The most commonly used forms are mentioned below:
Local port forwarding is the most commonly used compared to other types of port forwarding. It is usually employed to send data from a different client application on the same system. With Local Port Forwarding, you can connect from your local computer to another server easily. You can also get around firewalls that are blocking certain web pages by using local port forwarding.
Remote port forwarding enables applications which are on the server side of Secure Shell (SSH) connection to access services on the SSH’s client side. There are other proprietary tunneling schemes as well that utilize remote port forwarding for the same general purpose.
In simple words, remote port forwarding lets you connect from the server side of a tunnel to a remote network service which is located at the tunnel’s client side.
Dynamic Port Forwarding lets you traverse through a firewall or NAT by using firewall pinholes. The goal of this method is to allow clients to connect securely with a trusted server which is acting as an intermediary for sending/receiving data to one or many destination servers.
To send any request over the internet, packets of data are created and sent over the internet. These packets contain the details of your request, which also includes the destination of your computer or device.
Normally, a network router examines the header of an IP packet before sending it to any linked and appropriate interface. It, in turn, then sends the data to the destination that’s in the header.
But Port forwarding changes things a bit. In port forwarding, the intercepting application (your VPN client) reads the packet header, notes down the destination, and then rewrites the header information before sending it to another computer or server—one which is different from the computer/server you intended.
That secondary host destination may be a different server using a different IP address, a different port, or a completely different combination of the two. In case of a VPN or proxy, this secondary destination are usually the servers employed by the provider which mask or cover your original IP address.
The following example will help in explaining how the port forwarding feature works.
In the following example, IP Address 184.108.40.206 sends a request to 220.127.116.11 on Port 90. An intermediary host—18.104.22.168—intercepts the packets, rewrites the packet headers and sends them on to IP Address 22.214.171.124 on Port 9090:
|Makes a request to||Actually sends to|
The host, 126.96.36.199, responds to this request, sending it to 188.8.131.52. Then 184.108.40.206 rewrites the packet—indicating that the response is from 220.127.116.11—and sends it to 18.104.22.168:
|Sends its response to||Forwards the response to|
As far as 22.214.171.124 is concerned, it has sent a request to 126.96.36.199 on Port 90 and has received a response back from 188.8.131.52 on Port 90. But this isn’t what actually happened. The traffic never really touched 184.108.40.206. But, because of the way the packets were rewritten, 220.127.116.11 sees that it has gotten a response from 18.104.22.168.
The perceived destination is always from the perspective of the requesting computer. As you can see in the diagram: despite 22.214.171.124 becoming the real-time destination for traffic from 126.96.36.199, the destination for all traffic (as far as the requesting host knows) is 188.8.131.52.
You can learn more about how Port forwarding works via the video below:
Port Forwarding feature comes in pretty handy in lots of stuff that we do at home or at work. The following are some important use cases of Port Forwarding:
Are you having trouble getting your favorite multiplayer games or chat program to connect to the Internet? Does your tablet’s Web browser fail despite being connected to a Wi-Fi network? Your problem may be a blocked port on your router, and that’s easy to fix.
Your router stands between your devices and the Internet, making sure that any data coming in and going out is directed properly.
Imagine your router as a wall that keeps out unwanted and harmful traffic while opening ports to permit useful traffic such as Web pages, games, and file-sharing programs. Ports are like doors in the wall reserved only for useful traffic, and your router does a good job of automatically configuring most of the ports you need to safely use the Internet.
In some cases, however, you need to tell your router to open up a certain port so a program won’t be blocked. This is where you’ll need PureVPN’s Port forwarding feature.
There are many reasons why you’ll need PureVPN’s port forwarding add-on. It’s a known fact that VPNs and Port Forwarding don’t usually work together. If you want to use Port Forwarding, you will have to turn off your VPN service. But this will expose you to online threats of all kinds.
This is where PureVPN’s port forwarding add-on comes in. Using this add-on will let you use Port Forwarding and PureVPN simultaneously.
Similarly, Port forwarding does not work on your PC. But with PureVPN add-on, it will work on your PC as well.
Port forwarding is an excellent way to preserve the privacy of your public IP addresses. In a world where hacking and surveillance are pretty common, it is necessary for netizens to employ measures which keep their original IP address hidden.
Hackers or surveillance agencies can find a lot about you if they manage to trace your IP address. They’ll be able to track your browsing activities and have your browsing history at their disposal. They may also be able to hack into your browsers directly or monitor any emails, messages, or content you send via your network.
Port forwarding protects you from all these hassles. Your devices and servers remain protected from unwanted access, while your activities remain hidden from all kinds of spies and hackers. Port forwarding is transparent to the end user, while it adds an extra layer of security to networks.
Similarly, port forwarding is beneficial for those who want to stick to a single IP address when using the internet. These can be entrepreneurs or people working for a corporate entity. They usually subscribe to a dedicated IP via a VPN provider and utilize the port forwarding feature to connect with that particular unique IP address.
Port forwarding is also useful for those who want to run a Web server or gaming server on a single network. Those wishing to connect to this network can easily do so via the port forwarding feature.
PureVPN gives you access to Port Forwarding feature while also ensuring that you remain safe in the process. Any data that you send to and from your device remains 100% protected and safe. And no matter how hard a hacker tries, your online communications remain hidden and secure with the best encryption methods.
So what are you waiting for? Try PureVPN now and use Port Forwarding without being exposed to its vulnerabilities.
You can check if your port is open or not through port checking services like CanYouSeeMe.org and ismyportopen.com.
A big problem with the manual setup of Port forwarding feature via your router is that your online communications are not as safe as you think they are. There are plenty of vulnerabilities that come across those who use Port forwarding without any added security measures in place.
Port forwarding is the biggest security issue in our industry. How do we rid ourselves of easy yet evermore challenging in the age of #IoT?— Hagai (@HagaiFeiner) October 24, 2016
Port triggering is similar to port forwarding except for a few key differences. When you set up port triggering, it closes the port that you have chosen. This port shall only open when it is triggered by an outbound communication. The port will then close after a specified period of time once the outbound communication that triggered the port opening ends.
This is helpful in increasing the security of the connection because it gives control to the local device to open the connection, or otherwise keeps the port shut. This helps in removing the risks associated with port forwarding when a port remains open for a long time even when it’s not under use.
As you may know already, some applications and games require certain ports to be opened to function successfully. Port forwarding and port triggering can both be used for allowing devices to access services outside the network. However, their processes are slightly different.
Port forwarding allows external connections for an indefinite period of time, so it’s considered less safe as the ports are left open on the router. Port triggering, however, allows external connections for a specific period of time, thereby making it more secure and flexible than its counterpart.
UPnP, also known as Universal Plug and Play, is a protocol that solves some of the security issues raised by port forwarding. It allows apps on your devices to open ports when needed and close them once they’re done. It’s more convenient as it saves you from the hassle of opening and closing ports manually.
Finding and opening ports on your router is easy. Follow the steps: