PC cannot connect to the router
The configuration web page for the router would not be able to show up if the router and your computer are not connected.
If the PC and the router are joined to the network by LAN cables, they would not be able to connect if any of the network cable connections are loose. A possible indicator is that there is no light at the LAN port of the PC. In Windows, if you click the network icon and click to “View network connections”, the LAN port shows “Disconnected”. Please ensure that all the connections are tight.
Sometimes, disconnecting and reconnecting the LAN cable solves connection problems if DHCP is used, because the DHCP server and DNS server are reset. (Also, dis-associating and re-associating to the wireless network has a similar benefit as unplugging and re-inserting the LAN cable.)
The router, the computer, and the gateway must have IP addresses on the same network. For example, if you use a subnet mask of 255.255.255.0 and the gateway IP address is 192.168.3.1, all the IP addresses must be unique and be of the form 192.168.3.X.
Check whether the router and your computer are connected on the same network by running the ping command to ping the IP address of the router.
Alternatively, type the following in the router's Linux terminal: ping 192.168.3.77 (if your computer's IP address is 192.168.3.77 for example.)
They should be able to give the ping responses.
An IP address conflict would cause unstable pings. Switch to another address and ping the conflicting address to check.
If using a Windows computer, you should run the command arp -d * if the network configuration has changed. This is to delete the address resolution protocol (ARP) table in Windows as it may not update fast enough.
If the ping still cannot get responses, try disabling the firewall on your Windows computer. The Windows Firewall on your computer may prevent it from sending back a ping response. Disabling the firewall may be a security risk, so you should take the precaution of disconnecting the Internet first.
PC Ethernet and WiFi adapters
If your PC has both Ethernet and Wifi adapters, they must not have the same subnet. Otherwise, packets from the PC may not be directed to the correct network.
Mobile phone cannot connect
A mobile phone or any Wifi user would not be able to connect to a wireless router if there does not exist a DHCP server on the network. Please make sure that there is one, and only one, DHCP server to assign IP addresses automatically to users. You may refer to Section 5.2.2 DHCP Server to enable the DHCP server for a router. The option is found in Network ➤ Interfaces ➤ LAN ➤ DHCP Server.
Mobile phone connects but cannot access Internet
A mobile phone or any connected Wifi user would not be able to access the Internet if the default gateway is not set correctly on the router. The option for the default gateway is found in Network ➤ Interfaces ➤ LAN ➤ Common Configuration ➤ General Setup ➤ IPv4 gateway. If this router has enabled a DHCP server but the gateway is at a different IP address please add a DHCP option according to Section 5.2.2 DHCP Server. The DNS server should also be set. This option is found in Network ➤ Interfaces ➤ LAN ➤ Common Configuration ➤ General Setup ➤ Use custom DNS servers.
Unresponsive web page
Symptom: The 'XML Parsing Error' may occur if a certain option was changed and the web page did not update in time.
XML Parsing Error.
Solution: Re-enter the IP address into the browser. For example, if the current URL is 192.168.21.1/cgi-bin/luci/;stok=7266f0d55..., delete the right hand side to leave the IP address of 192.168.21.1 and press Enter. This would bring you back to the login page of the device.
Symptom: The router does not respond. Solution: Turn off the router for 10 seconds and then turn it on again.
Resetting to factory default
To reset the router to the factory default settings:
While the power is on, hold down the reset button for 8 seconds and then release.
Another method is to enter the following command into the router's Linux terminal:
mtd -r erase rootfs_data
After a while, the flash would be erased and the router would reboot into its factory default state. The firmware version remains the same as the latest firmware loaded onto the board.
Unable to update firmware onto the board
Tera Term VT cannot upload the images to flash. The possible reason is due to firewall has been turned on. To resolve it, firewall need to be turned off.
After that, the firmware could be successfully updated.