Explain the Difference Between a Filtered and a Closed Port
If a port is closed you know that either the device is not listening on the port or that there is a firewall blocking it. Occasionally a service will respond with a UDP packet proving that it is open. Nmap Null Scan How To Use Nmap Nmap Tutorials Port Scanning Tutorial Scan Tutorial Cyber Security 46 Excel Conditional Formatting. . Go to Firewall Control Panel by selecting startRun and type firewallcpl. Ports can be closed in this context filtered through the use of a firewall. IT administrators should consider blocking closed ports with a firewall where they would then become filtered ports. The computer responds and asks if there is anything it can do for you. The port is also marked filtered if an ICMP unreachable error type 3 code 1 2 3 9 10 or 13 is received. Next I tried to use the UDP scan. When you scan a port and its determined to be filtered or stealthed it means your scanner didnt get any respon...