The other day, I was working on a friend's computer, when a Symantec error popped up: "The traffic from IP address xx.xxx.x.xx has been blocked for 600 seconds." When I investigated, the logs showed it was a port scan attack from another computer on the network (private network, but a lot of people on it). Further investigation revealed it was actually my computer in the other room that was sending the port scans. Since then, I've run several anti-malware programs on my computer, and every one has come out negative (well, some tracking cookies, but nothing big). I've tried Malwarebytes, Spybot S&D, Avast, Superantisyware, and Hitman Pro (all with completely updated definitions). Is there another possible, legitimate source for these port scans, or should I keep downloading and running other anti-malware programs?
Thanks!