Just tested WOL SMS utility with RUT9XX_R_00.06.04.5 firmware version and can confirm that functionality should be working.
Router should both send WOL packet to specified MAC address and reply to this SMS command indicating that WOL packet was sent.
- If you are using older firmware, try to upgrade router's firmware to the latest one. Latest firmware can be downloaded from here.
- If you are using latest firmware, make sure that correct MAC address is entered in SMS Utility rule (with ":" as separation symbol). Also make sure that you are sending correct specified "SMS text" with appropriate selected authorization. Example: If you have specified the following settings:
"wol" SMS message should be send to the router (i.e. without administrator's password or serial number)