Port scans through NAT router?

Hi,

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?

Thanks,
Jim
Received on Tue Feb 7 20:58:00 2006