How to determine if a port is open or blocked using telnet
Procedure Steps
OnGuard must have certain ports available for use (unblocked) in order to function correctly.
Telnet must be available. To enable, locate the Control Panel. Select Programs. Select Programs and Features. Select "Turn Windows features on or off". Once the box loads, locate Telnet Client and check the box next to it and select OK.
Once the software installs it will be available in Command line for use.
To test a port from any computer on the network using telnet:
1) Click Start, and then click Run.
2) Type cmd then click [OK] to open the Command Prompt window.
3) At the command prompt, type telnet servername> port number>
Note: Replace servername> with the computer name of the OnGuard server and port number> with the number of the port you wish to test. For example to test the Communication Server RPC port on a server named Cranberry you would type:
telnet cranberry 4001
4) Telnet will attempt to make a connection to the computer and port specified.
- If the port you are testing is open, the cursor will continue to flash in the upper right corner of the command prompt window.
- If the port is closed or blocked, you will get a connection failed message after a few seconds.
Note: Telnet may be disabled and/or blocked on Port 23, consult your IT administrator for more information.
