The Reset button is located on the back of your CUJO device just above the ethernet cable sockets.

The Reset button is used to perform a Factory reset procedure.

Factory reset (DHCP server reset)*

Factory reset procedure for firmware versions from 6007 and up:
  1. Hold the reset button for 10 seconds until the eyes start alternating and then release it.
  2. Wait for approximately 2 minutes for CUJO to reset.

* Applicable to all firmware version up from 6007. For firmware versions 5003 and below the reset procedure is different. Please see HERE.