Everything You Need To Know About VPN Port Forwarding

Last Updated: July 30, 2021

Virtual meetings and remote work are now more common than they used to be, thanks to the advancements in technology. Also, online gaming has become a favorite pastime for a lot of people.

Port forwarding is one important tool you can use either for business or personal activities. With port forwarding, co-workers can access software on a host system remotely. You could also use port forwarding for torrenting. It is available on WiFi routers and VPNs.

So, what exactly is port forwarding, and how does it work? This article will discuss what port forwarding is about, how it works, its setup processes, benefits and risks, and other important information to help you understand it.

What Is a Port?

A port is involved in receiving data sent from one end to another, and it facilitates data flow within your computer or incoming traffic from the internet or a local network. It could also be described as a unique number designated to a protocol. It controls the transmission of data over the web or between computers. For example, data transmitted through HTTPS (Hypertext Transfer Protocol Secure) uses port 443.

Port numbers act like tags used to differentiate between protocols and also prevent data conflicts. A port number is also important for the security of a network because you could prevent a protocol from running on your network by blocking its port.

What Is Port Forwarding?

A computer has over 60,000 ports, and only a fraction of those ports are frequently used. When you assign the free ports to other devices or services, that’s called port forwarding. Programmers, torrents, or businesses usually use port forwarding.

Port forwarding or tunneling is also called port mapping. It redirects incoming connections to selected devices or applications on a private network.  It is the process of intercepting data being transmitted to your IP address and then rerouting it to another location. With a VPN, the location may be that of the VPN server the provider operates.

With a NAT (Network Address Translation) firewall active, another device on the internet that tries to connect to your device will be blocked. NAT facilitates IP address sharing. NAT prevents unsolicited connection requests because they lack port numbers. However, port forwarding allows you to accept unsolicited connections by assigning them with a specific port number. More so, port forwarding makes it possible for devices on specific ports to connect through the firewall and access software and services on the host device.

Most times, VPNs and wifi routers are equipped with default NAT firewalls. When multiple devices are connected to a VPN server or router, they all share a public IP address but still maintain their unique IP addresses.  

As useful as port forwarding can be, you could also be exposed to several risks online if your connection is not properly secure or if a hacker has port details. This is one reason most VPNs don’t support port forwarding.

How Does Port Forwarding Work?

As we said, computers use ports to differentiate between multiple protocols that are active on the system. This allows your computer to run so many protocols and services seamlessly. 

Durin port forwarding, a request is sent across the web and a VPN or router client intercepts the data packet and analyses it to see the header and destination before encrypting the data. The data packet is then forwarded to a new destination.

It’s like a house where everyone uses the same mailing address, but all have separate mailboxes. When the postman delivers all the mail sent to the house, the house manager goes ahead to sort out what mail belongs to who and places it in the right boxes. Outgoing mail also passes through the house manager, who forwards it to the right destination.

Types of Port Forwarding

There are three types of port forwarding that serve different purposes. So it depends on what you want to achieve. The three types of port forwarding are:

Local Port Forwarding

Local port forwarding is the most frequently used type of port forwarding. It forwards data packets securely from a client program (a VPN provider or router) running on your device through an encrypted tunnel and transmits the information to a specified port or destination. Local port forwarding also allows you to bypass firewalls to access certain pages.

Remote Port Forwarding

Remote Port Forwarding permits any device on a remote server to connect to a TCP port. This form of port forwarding comes in handy when you’re trying to create external access to an internal web server. It is very useful for remote staff to log on to a secure server from wherever they are.

Dynamic Port Forwarding

This is a unique form of port forwarding that facilitates firewall bypasses through “firewall pinholes.” It allows you to create a secure connection through a secure server that acts as a middleman, routing data packets to other servers. You can use this as an extra layer of security when you’re connected to an untrusted public network.

How To Set Up VPN Port Forwarding

It is not advisable to use port forwarding when connected to a VPN, but several VPN providers now include port forwarding options. Apart from the added VPN features, you still get the same access and functions of port forwarding.

Many VPN providers don’t support port forwarding because they use NAT firewalls to prevent malicious connections. However, in the course of blocking these unsolicited connections, the firewall might block other connections a user might want. This usually affects users that are into torrenting.

However, some VPNs don’t have a built-in NAT firewall, so you don’t need to port forward. Either way, here are some general steps for port forwarding with a VPN (please note that the precise steps may differ among VPN providers):

  1. Activate port forwarding in the VPN client or your account dashboard.
  2. Indicate what ports should be open on the VPN.
  3. Change the listening port on the program using port forwarding (a torrent client, for example) to match the ports chosen in step two.
  4. Disable UPnP and NAT-PMP in the application settings.

You should be done after the brief steps. You can log on to CanYouSeeMe.org to check if the forwarded port number is working perfectly.

How To Port Forward On a Router

As with VPNs, the setup process for port forwarding depends on the router provider, model, and firmware. However, some general steps should be alike:

  1. Once you’re connected to your router, locate your router admin panel. You could easily do so by entering 192.168.0.1 0r 192.168.1.1 into your web browser’s URL bar.
  2. Type in the admin username and password. If you’ve not already changed your admin details, then details for your router type could be available online.
  3. Navigate to the port forwarding section of the router settings.
  4. Create a port forwarding rule for the devices you want to port forward. For this step, you’ll need their IP addresses and port numbers you want to use.
  5. Once you’re done, save your settings and test run it.

If you’re not familiar with your router settings or how routers work generally, you could avoid port forwarding altogether or hire a professional.

Port Triggering vs. Port Forwarding

Generally, port triggering is actually almost the same thing as port forwarding, but it just works differently. Port forwarding always designates a specific port to a device, but port triggering takes a dynamic approach.

A computer on an internal network connects to an external server via a specific port with port triggering. The router then finds the connection and triggers a port forwarding rule to the internal computer. The data packet is the same as the forwarding rule and then forwarded to the internal computer for a while.

Port triggering is useful, especially when two devices need to use one external port. However, the process of implementing port triggering can be very complex and difficult to use.

Static vs. Dynamic Port Forwarding

In simple terms, static ports don’t change, while dynamic ports change whenever you make a new connection. In terms of security, dynamic ports are recommended because they make it hard for hackers to intercept your connection.

Static ports are easier to use on routers because you don’t have to change your port settings every time you want to establish a network connection. However, with some VPNs, you only get static ports.

Dynamic port forwarding is widely used because it is less complicated to set up and use. The process makes it possible for providers to recycle ports that they didn’t use and assign them to other computers or services. However, you cannot use dynamic port forwarding if you’re after remote access or torrenting because both activities require static ports.

Advantages of Port Forwarding

Port forwarding is possible with routers and VPNs. On both platforms, they offer a variety of benefits such as:

1. Granting Remote Access: It gives you or others the ability to connect to a port associated with a personal or work network remotely. Whether you or co-workers need access, port forwarding makes it possible in short easy steps.

2. Enhanced Torrenting Speeds: With port forwarding, you can seed (upload) or leech (download) from a torrent faster without a NAT firewall blocking your access. However, in reality, you don’t need port forwarding for many torrent sites, including BitTorrent.

3. Hosting Online Games: Port forwarding creates a direct connection with games servers with a specific IP address. This is handy for inviting friends to play games with you, and is also useful if your games are having a difficult time connecting with a game’s server.

4. Bypassing NAT Firewall: Another important use of VPN port forwarding is for bypassing a NAT firewall. If you use a VPN service, there’s a strong probability that the application has a built-in NAT firewall that blocks unsolicited requests. While a NAT firewall is excellent security, it could prevent connections that you might want. Port forwarding allows connections that your firewall could block.

5. Connection Sorting: As we described earlier, ports allow your computer to create a link to protocols and other connections. When your computer tries to receive data, for example, it looks out for a port number to know its destination. This is how your computer avoids sending or receiving data packets through a single port.

Risks of Port Forwarding

Although port forwarding is a very useful tool for many reasons, there are several risks and disadvantages you face with this process. However, these risks depend on why you’re port forwarding and what programs can listen to your ports. Still, here are some of the risks you face:

1. Vulnerabilities to Hacking: Port forwarding exposes you to multiple unsolicited connections. This translates to exposure to hackers because if your friends or colleagues can access your computer remotely, so can a hacker. This is one major reason VPN providers have considered and why only a few allow port forwarding. With the “right” information, hackers could take complete control of your computer.

2. Port Fail: If you’re using a VPN that allows port forwarding, you could experience “port fail” errors that expose you to attack. When your port fails, an attack could see your real IP address, as well as the IP addresses of others connected to your network. Even if others connected to your network don’t enable port forwarding on their devices, they could still be at risk. While several VPN providers protect against this, others may leave you vulnerable.

Conclusion

Port forwarding is an essential tool to make a certain service or file on your computer accessible to others on the internet or a local network. Whether it’s for personal use or business, port forwarding makes sharing easier. However, it has a couple of benefits and several risks you should consider before using it.