Your host isn't likely to care unless it causes them grief. There are so many scans happening at any given moment I doubt any of the targets will notice yours.

I do vaguely remember one of these, "I scanned the whole internet! It's easy!" stories from years ago where the author wound up receiving an email from someone at Electric Boat who told them, "Please don't portscan us. We're required to call the FBI when it happens." Your host would probably be "very annoyed" if they received one of those, but I doubt anyone cares enough to send such a message nowadays.

>I scanned the whole internet!

This one? http://census2012.sourceforge.net/paper.html

My favorite part is the animated day/night cycle at the end.

Portscan them more so they fix their process.

1 packet going out to 4 billion hosts probably doesn't even matter next to a few 4K video streams.

I expect if author had launched it through CGNAT, someone wouldn't have been pleased. (Correct me if I'm wrong)

Presumably CGNAT implementations have some safeguards to prevent one client from exhausting state tables.

I don't know if the tool is called Massscan (I thought there is a tool called something with rabbit) but I followed a security blog a few years back and since then I had the impression that scanning all ipv4s is basically a solved issue.