Why would you use that Remoteboot thing when you can do the same with Wake on Lan? Many routers have it in their web interface. To my surprise I can even wake up my Macbook via wifi (from sleep mode, didn't try complete power off).
WOL depends on sending a "magic packet" which is not transmittable out of the LAN. It is an Ethernet packet with the MAC of the card, and not TCP/IP, so will not traverse a router. Enabling a router to respond to WAN commands is not considered a good idea, there you really do want a very good security protocol, otherwise scans will find it and things happen afterwards.
Sleep as well ( depending on the actual level) just means the screen is off, and the system is running at the lowest speed the processor can run at, along with all RAM swapped out and most applications not given any processing time, the processor only responding to interrupts and the hard drive being commanded to idle. Low power state, not off.
I hope the OP is implementing very good security on the device, as it will either be open to packets via a DMZ on a router, or will be internet visible. Checking the sending side is within an acceptable network block ( reduce the sites that can attack to the IP block of the main user) along with using a good long password or PKI communications are really needed. There are enough vulnerable IOT devices out there already.