What is the difference between the WiFi password and the admin password?

The WiFi password (also called network key) is what you use to connect WiFi devices to the modem router's network. This password is unique to your device and is printed on the product label on the bottom of the modem router. The admin password is what you use to log in to the modem router's web interface at http://www.routerlogin.net to change settings. The default admin password is password.