Sometimes ISP (Internet Service Providers ) by Ports for communication to block spam and viruses from spreading across the network. CanYouSeeMe.org is an online Open Port Checker Tool that remotely verifies if a port is open or closed and check to see if a server is running or a firewall or ISP is blocking certain ports.
The interface is simple, Your IP address is identified and just enter port number that you want to check.
