How to use Telnet command to check if network IP and Port is accessible through your internet connection. Follow the step below to check.
Step 1: Go to command prompt Go to Start>Run>Type cmd and press ENTER. Or you can go to Start>All programs>Accessories>Command Prompt
Step 2: Once in command prompt get the IP and Port of the network you would like to test whether it is accessible. For example IP: 192.168.3.5 and Port: 9011. Then use telnet command as follow
Telnet 192.168.3.5 9011 and hit ENTER. You will see black screen with blinking cursor which indicate that the network IP and port is accessible.
If the network IP and port is not accessible it will show connection failed on the command prompt. See screen shot.