When troubleshooting network connectivity issue on customers there are times you need to do quick double check on connectivity such as ensure client has access to specific TCP port to remote host or IP. One easy way to perform those TCP connectivity checks is by using Telnet client. However, it can be a little time consuming going to the GUI process to add Telnet Client feature on Windows 7 and later operation system. One easy way to do it is to install Telnet Client feature via command line.
You can do that by typing the following elevated command:
dism /online /Enable-Feature /FeatureName:TelnetClient
Now using Telnet client you can test and check if the remote system has TCP open or closed, just by typing:
Tenet <Destination IP> TCP_Port
Telnet 10.1.1.1 80 (It will check if TCP 80 is open in the remote System)
After using it to perform connectivity tests, Telnet client can be removed by using the following elevated command:
dism /online /Disable-Feature /FeatureName:TelnetClient
That is it and happy troubleshooting!