Recently, there was a telecom activity that offered free fiber optic modems and set-top box devices. So, I signed up for a 20Mbps fiber optic plan from the telecom company. The stability and speed of this new connection is much better than the previous ADSL broadband I was using. However, due to some tinkering needs, I had to use port forwarding. I have a Xiaomi Mini router at home, but unfortunately, the port forwarding feature in the router settings didn't work at all. At first, I thought this feature was just for show, but after searching online, I found out that it was due to limitations imposed by the telecom company. So, let's go through the steps of configuring port mapping on the telecom modem.

1. Change the public IP address

Dial 10000 and ask the customer service to check whether your fiber optic connection has a public or private IP address. If it's a private IP address, ask them to change it to a public IP address and restart the modem for the changes to take effect.

2. Disable the wireless function on the modem

The modem has a built-in wireless function, but it's not very useful for port mapping. To enable port mapping, we need to disable this function and use the wireless function of the router instead. Open a browser and go to http://192.168.1.1/. Enter the username and password (which can be found on the back of the modem). Go to the "Network" tab, select "WLAN Settings" and then "Advanced Wireless Settings" on the left. Uncheck the "Enable Wireless Network" option and click "OK". Note that the steps may vary depending on the model of your modem. In my case, the model is TEWA-500E.

3. Change the modem's connection mode

Go to the telecom company's official website (http://www.189.cn/) and log in with your broadband account and password. Go to "My Services" -> "Broadband Service Inquiry" -> "Modify Router Bridge" -> Change it to "Bridge Mode". Note: You need to remember your broadband account and password for this step, as you will need to use PPPoE dial-up on the router to connect to the internet after making this change.

4. Set up PPPoE auto-dialing on the router

After changing to bridge mode, the modem no longer has routing functions. Connect the modem's LAN port to the router's WAN port. The router will detect the internet connection type. It used to be dynamic, but now it should be set to PPPoE auto-dialing. In the settings of the Xiaomi router, go to "Common Settings" -> "Internet Settings" -> "Connection Type" -> select "PPPoE" and enter your broadband account and password. Set it to auto-dial.

5. Port mapping

After completing the above steps, you should be almost done. Now you can set up port mapping without any issues. The method for port forwarding may vary depending on the router model, so you can search online for specific tutorials. To check your public IP address, you can refer to this tutorial: How to change your public IP address. Also, keep in mind that your public IP address may change when you reconnect, so you may consider using DDNS (Dynamic DNS) functionality. You can search online for more information.

Some content references: Changing default settings of telecom modems. Special thanks to the author for sharing.