How to Troubleshoot WAN Configuration When Internet Cannot be Accessed

Introduction
This document describes how to troubleshoot the configurations when Internet was connected but there was no available network.
 
Prerequisites
1. a UTT Business Router (hereinafter shorted as “the Router"), such as UTT router N518W, AC750W, AC750GW, AC1220GW, ER518, ER840G and ER4240G. Firmware Version: 3.0.0 or above
2. a PC/laptop connected to the Router wirelessly or through an Ethernet cable
 
Troubleshooting
Login the router Web GUI and check WAN Configuration.
 
1. Check the Gateway IP Address, Subnet Mask and Gateway will be filled automatically by the system once you enter the IP Address in the bar. (Default Gateway is 192.168.x.1 if IP Address start with 192.168.x.x, here takes gateway IP 192.168.20.250 as an example).
 
2. Check the Operation Mode, usually Internet access should work with NAT Mode.
 
3. Check the interface bandwidth and select proper negotiating rate at Interface Mode (auto-negotiation may be not compatible with, please configure this manually based the bandwidth the ISP gives you).