Canyouseeme is a a free utility for remotely verifying a port is open or closed. It will be useful for users who wish to check to see if a server is running or a firewall or ISP is blocking certain ports.
can you see me, CanYouSeeMe is open port check tool is a simple but useful web-based utility for figuring port is open or notOpen Port Checker
ports allow software applications to share hardware resources without interfering with each other. Computers and routers automatically manage network traffic traveling via their virtual ports. There are 65,536 ports to choose from.