If you ever need to check if a service is running and listening on a specific port on a server, and the server is online and allowing the connection, Telnet can be a great first tool to use to identify a possible issue.
Installing Telnet On a Windows PC
- Open your computer control panel.
- Go to Programs.
- Click Programs and Features.
- Select the “Turn Windows features on or off ” option.
- Check the “Telnet Client” box.
You can also install it from the command line using the command:
To use Telnet, open your command prompt and type in the telnet command using the following syntax:
telnet [hostname or ip address] [port number]
For example, you can telnet into an SMTP server using the following command:
telnet smtp.example.com 587
If the server is up and running, the port is open in the firewall, and the SMTP server is listening correctly at that port, you will be greeted by some text:
To End A Telnet Connection
- Escape Character is ‘CTRL+]’ (CTRL + Right Bracket)
- Type in the word ‘quit’ without single quotes.
- Hit the ‘Enter’ key on your keyboard