An nmap scan (WAN side) on my Netgear R7000 router indicates that there are two ports open: 80/tcp (http) and 1720/tcp (h323q931). My method to perform a WAN side scan on the router is to access the Internet through a hotspot on my smartphone to place myself on a separate network and run nmap against the public IP address for my router's network (nmap -Pn (public IP address)).
To make matters more interesting, a GRC ShieldsUP scan indicates all ports are closed. UPnP is not enabled (i.e. the box us UNchecked) and I have not enabled port forwarding for any ports. I have rebooted the router and run the scan from separate Windows and MAC computers (connected to the separate network created through my phone's hotspot) with the same results every time i.e. 80 and 1720 are open.
And to add even more to the confusion, the router's logs do not record any attempts to scan the ports i.e. the logs category "Known DoS attacks and Port Scans" shows no entry for either the nmap or GRC scans.
Nighthawk R7000 AC1900 Router
I would greatly appreciate any help and insight into whether there is a security vulnerability here i.e. the ports are exposed and open to exploit, or if something else is going on that leads nmap to designate these ports as "open". Also, any information on why the logs are not recording these scan attempts would also be appreciated. Thank you in advance.