TCP 3 - Port Protocol Information and Warning!
Some common uses for port 81/tcp include web administration (cobalt cube), web proxy servers, McAfee Framework Service, TigerVPN (servers speed check), etc. If you're not running web services on this port, keep in mind it is also used by some trojans: How to Delete TCP IP Port: 5 Steps (with Pictures) - wikiHow Oct 03, 2019 TCP and UDP ports used by Apple software products Aug 27, 2019
What Is Port 443?
TCP Port Scanner, Online Port Scan, Port Scanning | IPVoid
Most Cyber Attacks Focus on Just Three TCP Ports
Some common uses for port 81/tcp include web administration (cobalt cube), web proxy servers, McAfee Framework Service, TigerVPN (servers speed check), etc. If you're not running web services on this port, keep in mind it is also used by some trojans: How to Delete TCP IP Port: 5 Steps (with Pictures) - wikiHow Oct 03, 2019