To scan the IPv4 Internet, I used the tool [`masscan`](https://github.com/robertdavidgraham/masscan) by security researcher Robert Graham. He has extensively made use of `masscan` in the security research he does. It provides latency measurements up to the millisecond.
I wrote a configuration file to run `masscan` on the entire Internet with the included exclusion list, and scan the top 5 open ports according to [speedguide.net](https://www.speedguide.net/ports_common.php). It is stored as `scan.conf`. I started the scan with:
This produces the output file `scan.bin`. You might want to make use of shards to scan only a portion of the internet per file as scanning the entire internet will produce a huge file that cannot be parsed unless you have enough RAM available.
To associate an IP address with a country, a geolocation lookup database must be used. I used two sources of geolocation databases; Maxmind's GeoLite2, and Webnet77's IPToCountry; to test the accuracy of either database.