Port forwarding: how to set up virtual server on Mercusys wireless router?

What is Port Forwarding?

Port forwarding is a way of making your router use a specific port to communicate with certain devices. By setting a specific port for your devices, you are telling your router to always accept requests for those ports and forward data to a device’s private IP address.

In order to understand port forwarding, it helps to understand a little about how routers work first. Your router’s job is to transmit an internet signal to all your devices over a local area network (LAN). To do this, your router assigns each device in your LAN its own local IP address. For example, your computer will have a private IP address like or

Then, on top of that, the applications and services on each device are also assigned a port number. For example, an application on your computer will have an IP address with a port number attached like or

With this unique IP address and port number, your router knows which program or service to send information to. This lets you and others access devices and programs on your LAN over a wide area network (WAN).


Please follow the steps to forward ports on your router.

I want to:

Share my personal website I’ve built in a local network with my friends through the internet.

For example, the personal website has been built on my home PC ( I hope that my friends on the internet can visit my website in some way and the port number is 90. The PC is connected to the router with the WAN IP address


Step 1 Log in to the router’s web management page:

How to log into the web-based interface of the MERCUSYS Wireless AC/AX Router?


Step 2

Click on Advanced->NAT Forwarding->Port Forwarding, then click Add button.


Step 3 In the Service section of this screen, type in the detailed information you confirmed with the service’s provider. For this example, if you want to open port 90 for only one of your devices, you can configure it like below:

Service Name: Select the service you want to use from the View Common Service list. If the View Common Service menu does not list the service that you want to use, you can enter the Service Name manually.

External Port and Internal Port: Select the service you want to use from the View Common Service list, then the External Port and Internal Port will be automatically filled in. If the View Common Service menu does not list the service that you want to use, you can enter the External Port and Internal Port manually. You should verify the port number that the service needs.


1. If you need to input a port range xx-xx when configuring the port forwarding, please leave the internal port empty.

2. The External Port and Internal Port usually can be the same.

Device IP Address: Select the device from the VIEW CONNECTED DEVICES menu. The Device IP Address will be automatically filled in. Or enter the device’s IP address manually in the Device IP Address field.

Protocol: Specify the protocol used for this application from the pull-down list, if you are not sure, choose ALL.


Step 4 Click the Save button to save the settings.

Note: To ensure the Port Forwarding will take effect all the time. You´d better assign a static IP address for your server, because its IP address may change when using the DHCP function. Or you can just do an IP address reservation for the server. To set up the address reservation:

  1. Go to Advanced > Network > DHCP Server and locate the Address Reservation section.
  2. Click Add in the Address Reservation section.

  1. Click VIEW CONNECTED DEVICES and select the device you want to reserve an IP for. Then the MAC and IP Address will be automatically filled in. You can also enter the MAC and IP address of the client device


Step 5 Go to Advanced->Network->Status page and check the WAN IP Address of the router. Now you can try to use the http:// WAN IP:port number (in this example: http:// to visit your personal website.


If the WAN IP Address of the router is not a public IP Address, but a Private IP Address, that means there is another NAT device connected to the WAN port of the Mercusys router, you need to open the service ports on that device as well.

Note For the CG-NAT ISP: Comporium and Direct link - radio service, provide the customer a private IP, that will cause you can’t use the OpenVPN or port forwarding and affect the NAT Type. You can contact the ISP and ask them to offer a Static IP address.

For how to find out the IP Address is a public one or a private one, please refer to this link:



A) If you want to open port 80 for a local device, please change the router’s remote management port (service port) number first since its default number is 80. As for the internal port, 80 is reserved for the local management and cannot be modified although the remote management port has changed.


Go to Advanced->System Tools->Administration, and then change the HTTP Port to other ports such as 8080 and Save.

B) Some models support different External ports and Internal ports. Here we will explain this configuration under different situations.

For example, if you want to open port 90 for only one of your devices, you can configure it like the instruction above.

If you have two or more devices ( & in this example) want the same port to be opened for a certain service, then you will have to use different External Ports.

For the Internal Port, please put in the actual port number (90 in this example), then create different Service port numbers for the two devices (like 9000 and 9001 in this example).

After this configuration, you can access the two devices using different External ports (Service Ports). In this case, you can use WAN IP:9000 to access and WAN IP:9001 to access

If port forwarding fails after you have done all the configurations above, please refer to this link for further troubleshooting: Why port forwarding feature is not working on my router?