Port Forwarding – What is it?

One of the critical reasons for using Port forwarding in Windows; Is that allows you to manage requests sent to your IP through the router. Most networks have a firewall to block incoming ports. The firewall blocks these ports to ensure network security, so access to data and services becomes more difficult without forwarding the Port.

What is Port Forwarding?

Port forwarding, or tunneling, is the behind-the-scenes process of intercepting data traffic headed for a computer’s IP/port combination and redirecting it to a different IP and/or port. A program that’s running on the destination computer (host) usually causes the redirection, but sometimes it can also be an intermediate hardware component, such as a router, proxy server, or firewall.

Of course, even though anyone sending data to a server isn’t aware of what’s going on, the request will still get to its ultimate destination.

How does it work?

Ports are how computers distinguish between multiple services listening on one computer.

Using ports lets a device run a myriad of different processes and services. Each service has its port – for example, email servers usually use port 587 while websites use port 80.

In total, there are more than 65,000 different ports, but only about 1,000 are used regularly. The others can be assigned to the devices or applications of your choice, and this process is called port forwarding.

To fully understand it, you should also know that, thanks to NAT (Network access translation), all the internal devices share the same external IP address.

So, let’s use a little allegory to explain how port forwarding works.

You can think of ports like doors to a house: your computer is at 1234 Daisy Lane and it has about 65,000 doors. If port 22, used for the SSH remote access protocol, is listening, imagine that door 22 on 1234 Daisy Lane is unlocked.

The trouble with NAT is that it provides different addresses internally and externally. To continue the house analogy, imagine that the outside world could only send visitors to Daisy Lane, not specific houses within the neighborhood. If a visitor asks for door 22 on Daisy Lane, the gatekeeper (representing NAT on the router) won’t know which house to send them to.

This is where port forwarding comes in. When you set a few router (or other default gateways) settings, it will be able to send inbound connections to the right computer within the network.

Types of Port Forwarding

There are three main types, each with different intentions and functions.

Local 

Local port forwarding is the most commonly used form of port forwarding which forwards data securely from a client application running on your computer. It allows the user to connect to another server through a secure tunnel and sends the information and data to a specific destination or port. Firewalls that block certain pages can also be bypassed when using local port forwarding.

Remote

This type of port forwarding allows anyone on the remote server to connect to a TCP port. Remote port forwarding is useful in establishing outside access to an internal web server, most often used by remote workers when accessing a secure server from home.

Dynamic

This is rare from port forwarding which allows you to break through a firewall using what’s known as firewall pinholes. It allows clients to establish a secure connection via a “trusted” server that functions as an intermediary, transmitting data to other servers. It can be used to provide additional security for a user connected to an untrusted network, in a coffee shop or hotel, for example.

Is Port Forwarding safe?

Yes and no. You are poking holes in your router by port forwarding. Nothing is ever safe online, and there’s always an underlying risk. On the other hand, you can’t connect to a game server or an external network without applying port forwarding rules. This leaves you vulnerable but only to specific traffic, and if the external device can’t communicate with you, it’s game over for them.

For example, you might have port 443 open for a database connection. Someone trying to FTP into that (which would normally be port 21) can’t communicate with port 443. It’s like trying to fit a square peg in a round hole.

If your router is strong security-wise and can easily dodge DDoS attacks, then opening ports is harmless. You can also use a Virtual Private Network, otherwise known as a VPN, to enhance your encryption level when it comes to port forwarding. A VPN supports both TCP and UDP ports as well as offers secure access to external servers.

Why is Port Forwarding important?

Port forwarding is critical for remote access to items on private networks. Since firewalls exist to keep unwanted visitors out, the visitors you want to get in are going to need a way to do so. Knowing the IP address isn’t enough: Requests need to be directed to the correct port as well. This extra required information helps keep unwanted visitors out and adds a further layer of security against DDoS (Direct Denial of Service) attacks.

Port forwarding functions incredibly well alongside various identity management software. Multi-factor authentication software, single sign-on solutions, and the like create an extra layer of security towards allowing visitors into particularly secure areas like file servers and databases.

Conclusion

Port forwarding allows you to open up a specific service on your computer to receive inboard traffic from the Internet. From video games to remote desktops, it’s a very useful tool. Port forwarding comes with some security considerations, but they can generally be overcome.