I rented a $6 server, gave it a fresh IPv4 address nobody had used before, and started a stopwatch. The first unsolicited packet arrived 3.77 seconds after the listener came up. It was a TLS ClientHello aimed at port 8443, from a host in a Linode range, and it landed before the machine had finished its second minute of existence. Seventy-five minutes later I had 1,212 events from 84 addresses across 15 ports. The interesting part turned out not to be the speed. It was that counting the s...