This example shows how to open port 3389 (which is used by Remote Desktop service). You need to find out what ports your application is using. For example WEB server (HTTP) is using port80 TCP, PCAnywhere uses ports 5631 TCP and 5632 UDP, etc.
Step 1. Set your computer with static IP address.
Note that the computer you are trying to redirect the traffic to should have static IP address. In our example the computer is set with 192.168.1.2 address. The Default Gateway should also be specified (it should be the router's LAN address: 192.168.1.1).
Step 2. Log into your router.
In order to login to the router start your Internet browser (e.g. Internet Explorer). Ensure that any proxy settings are disabled (in IE look under: Tools > Internet Options > Connection > LAN Settings). Then type the IP address of the router (the default IP address is 192.168.1.1)into the Address field and press "Enter" For example:http://192.168.1.1. After the connection is established, you will be prompted to enter username (the factory setting is "admin") and system password (the factory setting is "admin").
Step 3. Add LAN Client.
You first need to add a client (your Workstation) into the router before you can open any ports. Go to Advanced à LAN Clients. Type in the IP address of your Workstation (in our example it is 192.168.1.2). You can specify the name of this workstation under Host Name(optional). Click Add and then Apply.
Step 4. Adding ports.
Go to Advanced à Port Forwarding(Virtual Server). There is a list of pre-set ports in the router which you can choose from. If your specific application is not listed there, you can add the necessary ports yourself. Select the "User" Category and click on Add button below.
Enter the name for this entry under Rule Name. Then select the necessary protocol (on our case it is TCP). If there is a range of ports to open, specify the starting port under Port Start and the ending port under Port End. If you need to open just one port (like in our example), specify this port in all fields including the Port Map. Click Apply.
Step 5. Opening ports.
Go to Advanced à Port Forwarding (Virtual Server) and under LAN IP select your LAN Client (which we added in Step 3). This is the computer where the required traffic will be redirected to. Select "User" Category and you should see the rule which you have created in Step 4. Select it and then click on Add> to move it to Applied Rules section. Click Apply.
Step 6. Saving settings.
To save the new settings into the router's memory go to Tools à System à Save & Reboot. Click on Save & Reboot button. The router will save the settings and restart.
Now users on the Internet who will be accessing your public IP(in our example it is 126.96.36.199) using the certain application which utilises the specified ports (Remote Desktop with port 3389in our example), will be redirected to the specific computer on your LAN. Please note that from inside your LAN you will not be able to access your server using its public IP address (WAN IP on the router, e.g. 188.8.131.52). You need to use its local IP address instead (192.168.1.2).
Be aware that some Internet Providers are blocking commonly used ports like 80 and 21, hence you will not be able to host a WEB site or FTP site even if you will open the necessary ports in the router.