When utilizing Nmap to scan for open ports, my go-to commands are typically variations like nmap -A, nmap -O, nmap -p, and nmap -p-. However, I've frequently encountered filtered or ignored states for most of the ports, particularly on networks with robust filtration and firewall systems. Despite trying several Metasploit services (although not exhaustively), none have yielded exploitable vulnerabilities, suggesting a high level of network security. Despite this, I'm curious if there are known methods for bypassing such stringent filtration measures, So I can better expand my penetration field's horizon.