A scan over at
https://www.grc.com of my freshly installed WNDR4500 of the common ports revealed that while the ports are indeed stealthed, GRC reports that:
Unsolicited Packets: RECEIVED (FAILED) — Your system's personal security countermeasures unwisely attempted to probe us in response to our probes. While some users believe that "tracking down" the source of Internet probes is useful, experience indicates that there is little to gain and potentially much to lose. The wisest course of action is to simulate nonexistence — which your system has failed to do. Your counter-probes immediately reveal your system's presence and location on the Internet.
Can /will any one from Netgear's team explain/elaborate on what is taking place? Only router I've ever had which does this.