DavidR
3
Do you have a firewall?
A firewall should stealth your computer from the outside world. So the people running these port scans shouldn’t see your computer and attempt to exploit it.
The same first two groups of the IP address could signify an ISPs service and the the last two groups could be the randomly assigned number assigned to one of its users/members.
There are places where you can do a reverse IP address check, this returns the name of the domain when you enter the numbers IP (e.g. 256.256.256.256) address. Though it is time consuming and not very worthwhile.
Best to stealth you computer from the rest of the Internet and ensure that you OS is fully up to date, plugging these possible exploits when they are patched.