Eeekkk....

but scanning 12.216.171 should bouce my request from my isp's router back to mine
Nope....

Your router has two addresses the LAN, (local) on 192.168.1.1 and a WAN, (public), xxx.xxx.xxx.xxx. A packet destined for the WAN address from the local network will not pass through the router, it doesn't need to since it really reached the device at the LAN port. The device will recognize at the LAN port that the packet has reached it's destination and report back from there hence you see the HTTP management port open.

As jinxy said, get someone you trust at a remote location to scan the WAN address - the HTTP server should go away - if it doesn't then you have remote management turned on.... That is considered a bad thing......