In this tutorial, we will be using the SSH client command line utility on the Linux operating system. After that, the router will notice that you want to connect to port 21 and forward your connection request to the server on 192.168.1.10 address because of enabling the port forwarding option. When you want to connect to your home FTP server from the internet, you will first connect to the router that is on 200.X.X.X. Let’s say your router has a public IP address of 200.X.X.X. How does port forwarding enable outside connection now? For example, if you have set up an FTP server in your home, and the FTP service is running on port 21 with the server having an IP address of 192.168.1.10 – you will use this private IP address and port 21 in your router to set up port forwarding. When setting up port forwarding, you will specify the port of the service and the private IP address of the device that the service is running on (server). Even though all routers are different in how their user interface is organized, you will find this option with relative ease. You can do this by finding out the private IP address of the router/gateway and browsing to that address using a web browser. To set up the port forwarding, you will have to access the control panel or interface of the router. Most modern routers support port forwarding. This way the router will know where (or which IP address) to send the traffic to when the connection requests from outside networks are asking to connect to that specific port. The idea is that you will specify the port number for the service and tie it to the IP address of the server in your router or the gateway. Port forwarding is also known as port mapping. This is where the concept of port forwarding comes in handy. However, your router has no way of knowing where to send this data forward. Now, if you were to initiate a connection from the outside network or the internet, the connection will come to your router at first using the public IP of the router.

Imagine you have a home server set up in your home network, and you want to connect to the server from outside of your home network.Ĭhances are, your home network will be hidden from the public internet because it is behind your router, and the router will have the public IP facing the internet. In simple terms, port forwarding allows users from the internet or public network to connect to a host or a server that is behind a router or a firewall within a private network. Port forwarding is a kind of network address translation in which packets are redirected from one IP address and port combination (socket) to another while passing through a network gateway – a router or firewall. This means the SSH application/service runs on port 22 by default and all the data received or sent by the SSH application/service comes to or goes out from port 22. For example, the SSH service has a default port of 22. These network endpoints are made with the IP address and the port is called a network socket.ĭifferent applications/services have different ports that they use for communication. In short, the IP address and ports work together to create a network endpoint that sends and receives data from other network endpoints. If you want to learn more about ports and understand how they operate, take a look at this article on IP addresses, basic concepts and terms explained. The operating system creates different logical ports for different applications/services to communicate over the network. Since we want to cover port forwarding in this article, you must know how the ports function, why, and how port forwarding is done. When to use the Dynamic Port Forwarding?.

When to use the Remote Port Forwarding?.Remote Port Forwarding or Reverse Tunneling.

Types of SSH Tunneling or SSH Port Forwarding.

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