# Router default passwords and usernames Always try using a blank username or a blank password, in combination with all the possible usernames / passwords. Try using the full MAC address of the device as a password. Try using the same password as that of the Wi-Fi. If you have physical access to the router, look for any stickers with passwords on them: anything labeled `key`, `wireless key`, `WPA Key`, `password`, etc. Try using the serial number found on bottom of the router as a password.