Using Fiber Optic Internet on Flint (GL-AX1800) OpenWrt Home Router

Recently switched to CenturyLink for their affordable fiber service, but I don’t want to use the router/modem they provide. Therefore, I figured out how to use fiber with Flint (GL-AX1800) router instead.

When it comes to fiber optic internet, your service provider will install an optical network terminal (ONT) for you. In my case, CenturyLink gave me one ONT and a router, however, I want to use my own router and hook it up using an Ethernet cable capable of fiber-optic speeds. Using your own router might save you money, because many providers charge a monthly fee for supplying rented routers to customers. For me, I prefer the OpenWrt system for online privacy and customization! And, Flint has all I need!

CenturyLink ONT

Flint (GL-AX1800) The ONT installed in my garage

When the CenturyLink technician visits you to set up the service, you should ask the person to write down the PPPoE username and password before he or she leaves. The username is usually, and the password is randomly generated.

Kits for AX1800

Flint (GL-AX1800) All parts and components

Step 1: Set up Flint (GL-AX1800) and get into LuCi interface

Fiber Optic Flint

Plug the fiber internet cable into WAN

I could follow the instructions to set up Flint easily. After that, I logged into the web admin panel via its default LAN IP ( and then go to MORE SETTINGS > Advanced to install LuCi interface. LuCi is the default web interface of OpenWrt. When it’s installed, you can visit LuCi via a link, where you might need to enter your admin password again.

Step 1 Install LuCi

Step 2 Click Link

STEP 2: Set up VLAN Tagging on WAN

To use fiber-optic internet, we need to use a feature called VLAN tagging. The ISP technicians usually don’t tell you much details, but I googled it out that CenturyLink uses 201 as VLAN ID. VLAN tagging is located in Network > Interface > WAN, and then click “Edit”.

Step 3 Edit Wan

You will see the General Setup page of WAN, where you need to choose PPPoE protocol and add your PAP/CHAP username and password. The technician told me that the username is just the name part without “”. I just did what he said and then click “Save & Apply”.

Step 4 Save Input In Setup

Then we go to the Physical Settings tab to find the option called Custom Interface. If your ISP uses xx as VLAN ID, you just need to input “eth0.xx” and xx is the VLAN ID number. As I mentioned, CenturyLink uses VLAN Tag 201 on WAN, so I input “eth0.201” and then click “Save & Apply”.

Step 5 Click Customer Interface

These are all the steps. If it doesn’t work right away, you might need to reboot the router to let the new settings take effect.

About GL.iNet

GL.iNet builds network hardware and software solutions that bring affordable and secure network connectivity to families and businesses all over the world. We work with a wide range of industries, solving everyday internet problems in offices, and providing complex networking solutions such as smart buildings and IoT Networks. At GL.iNet, We believe all successful businesses build upon a strong and secure foundation, which is why our highest priority is perfecting network security and reliability for our partners.