Re: How can I shake off this guy ?
OK I have a couple suggestions.
First, fail2ban or similar. Protect your computer from the inside, always.
Second, a cheap appliance router/firewall. Defense in depth, and as long as you're careful they have a huge benefit because they just don't have much on them to exploit, which can be used to attack your network.
Third, something I can't really imagine why somebody else didn't say: Contact your ISP. If you're in the USA, then this sort of thing is illegal and the appropriate people will look into it if somebody complains. I've done it 3 times now over the years with scans that were especially pesky, and they all stopped shortly after they were reported. Whether it happened because my ISP put in a firewall rule of some sort, or somebody got a visit from law enforcement I don't know nor do I care.
I know it sounds ridiculous, you can't police the whole net right? But as in real life, the cops can't come if they don't get a call.
Help stamp out MBR partitions. Use GPT instead!