I have Sygate Personal Firewall running on my PC, which is connected to the Internet via a Netgear NAT router (RT314).
I am occasionally getting popups saying that Sygate detected a port scan, and when I do a backtrace, I can see that they're coming from various places "outside" my network.
The main reason for this post is that I'm curious, and I don't understand how that can be happening, because in the Netgear router, I don't have any ports mapped to my machine's internal IP address at all, and I definitely don't have the ports that are being reported by Sygate mapped in the router.
So, my question is "How can these port scans, on those ports, which are not mapped in the Netgear router, be getting through to my PC?". I thought that if I didn't map a given port in the Netgear, that the router would have nowhere to route any traffic on any unmapped ports?