A penetration tester ran an Nmap scan on an Internet-facing network device with the -F option and found a few open ports. To further enumerate, the tester ran a...

A penetration tester ran an Nmap scan on an Internet-facing network device with the -F option and found a few open ports. To further enumerate, the tester ran another scan using the following command: nmap -O -A -sS -p- 100.100.100.50
Nmap returned that all 65,535 ports were filtered
Which of the following MOST likely occurred on the second scan?