Giving URL to the clients with a port number is a complicated move by non-techy users and/or clients when accessing a website on their browsers or when accessing an application. It will be difficult for some also to remember port numbers. A ‘not-very nice’ move when giving URLs to clients is saying, “Please access https://www.example.com:1111” where ‘1111’ is the port number. So instead of letting your users or clients visit a website or access an application with a specific port, why not opt for just allowing them to remember only the domain name – example.com – and the rest of the work will be done by you as an administrator?

What is Port Forward?

What is a port in computer networking? A port is not a physical connection but it’s a logical connection that is used by programs and services to exchange information. Ports uniquely identify these programs and services that are running on a computer.

Port Forwarding is redirecting external inbound service requests to the correct internal computer on a private network. It also allows the users to access a specific URL without even bothered of what additional port to enter along with the URL because it will be the administrator’s job. By using Simple DNS Plus, you don’t just have a DNS server, but also a TCP Port Forwarder which is very helpful in this case of simply assigning and redirecting to a new port number instead of changing the URL.

Benefits of Port Forwarding

Port forwarding is the best way to safeguard your public IP address. If you only have a single public IP address, it allows you to let most of your applications be accessed over the internet securely. You just have to create multiple subdomains for your applications on your DNS and assign different ports each. This means that it allows you to use a single public IP address for all external communications on the Internet while assigning multiple servers and/or applications with different local IPs and ports on your private network. By doing so, you can hide from the internet or client-side what services are actually running on internally and limit access to and from your network.

On the other hand, port forwarding also helps in assigning ports for the applications which are transparent to the users over the internet and changing ports anytime without notifying users or clients. In managing one’s network, there will be times when administrators may have to change ports for testing, or any other possible network-related circumstances which can affect the access of the users over the internet if not properly configured. But with port forwarding, users can access your applications over the internet smoothly not knowing of the changes being made locally by network administrators.

TCP Port Forwarding with Simple DNS Plus

Simple DNS Plus has its simple TCP Port Forwarder plug-in. If the Simple DNS Plus server is connected to both the internet and on your local network (LAN), this can be used to forward connections from the internet to a server on the LAN.

On the Plug-In Settings” tab, there are a few settings you have to enter:

  • Listen on IP address. This is the IP address that the plug-in listens to for inbound connections.
  • Listen on TCP port. This is the TCP port that the plug-in listens to for inbound connections.
  • Connect to host. This is the server host name or IP address where the inbound connections will be redirected to.
  • Connect to TCP port. This is the TCP port of the server where the inbound connections will be redirected to.
  • Max. connections. This is the number of maximum connections that can be forwarded at the same time.
  • Idle time-out. If enabled, the connection will be lost or closed if reached the maximum time (either in seconds, minutes, hours or days) of idling or no data sent on both incoming and outgoing connections.

Figure 1 TCP Port Forwarder Plug-In Instance

This is also applicable for redirecting ports for your applications on your private network when local ports are modified for it to be accessed both publicly or privately.

Simple DNS Plus can also let you view the number of current connections, total connections, and the bytes transferred from clients to host and vice versa. There is also an activity log that will show individual connections that are accepted and closed. Simple DNS Plus’ TCP Port Forwarder has a very friendly user interface which makes it easier to understand and configure.

Figure 2 TCP Port Forwarder Connection Details

Figure 3 Simple DNS Plus Activity Log