Serious security issues?

[anon]

Your ISP is as responsive as mine

I'd say you download PeerBlock or P2PFire and block the offending IP if your firewall doesn't have that capability.

[Keikan]

I also thought about calling the hosting service the IP is from and reporting it.

Actually my ISP's tone was more like "Yea...so what?"

The thing most puzzling is, it's happening on 2 computers at the same time and sometimes the scanning will take a 5-10 min break.