This tool will Identify wether the port is open or not.
If the port is open, The output will be: Success Port 80 is Open and Danger Port 1 is Closed if not.
Input your IP or Domain on the first field (without http/https) and desired port on port field.
Example: google.com or 127.0.0.1 and port 80.
Server Applications use well-known ports such as 80, 443, etc. (well-known ports). Almost all of the ports on 80 (HTTP packets) uses for the webserver and 443 (https) for encrypted traffic. User registered ports(1024-49151) is used on p2p applications such as torrent, skype, etc.
To request a webpage from the internet, we need to use port 80 because it is the default port listener of the web. The port also needs to be open by the firewall so the request can go out. Ports also can be used on DNS or IP addresses because when you request via DNS:port, the computer will automatically translate it into IP address:port.