With tools such as ZMap and Masscan and general higher bandwidth availability, exhaustive internet-wide scans of full IPv4 address space have become the norm after it was once impractical. Projects like Shodanand Scans.io aggregate and publish frequently updated datasets of scan results for public analysis, giving researchers greater insight into the current state of the internet.

https://blog.talosintelligence.com/2019/03/ipv6-unmasking-via-upnp.html