Telnet is a legacy protocol for remotely connecting to a networked computer. If you’re having trouble connecting to a remote computer with your Telnet client, the following steps may help you troubleshoot the problem.

Bad network address

If you’re having trouble connecting with Telnet, first, verify the address you are attempting to telnet to is valid. One way you can verify that the address is valid and active is by pinging the computer or device. If you cannot ping the address, the address is wrong or you have network settings prohibiting you from getting to that address.

Telnet is not encrypted, and is considered insecure. Anyone listening to your network traffic can intercept the information, including passwords, communicated over a Telnet connection. If possible, use SSH instead. Contact the administrator of the remote computer to inquire about the possibility of using SSH instead of Telnet. Or, if you are the administrator of the remote computer, we strongly recommend you install and use a free SSH server, such as OpenSSH.

Verify the port you are using is correct. By default, the telnet port should be 23. However, some network administrators or users may change the telnet port to a different address for security reasons.

Telnet port 23 not open on remote computer or device

By default, many operating systems disable port 23 and telnet access on a computer. For you to telnet to a computer, that port must be open and the telnet service must be enabled on the computer.

Permission settings prohibiting telnet

Verify you have the permissions to telnet from your computer over the network and to another computer. Verify no firewalls between you and the computer or device you tried connecting to are being blocked. Also, verify telnet service is enabled on both computers.

Port 23 may be disabled because of security reasons. Telnet is unsecure and passes all information including username and password as plaintext. If port 23 is closed, try using SSH instead of Telnet.

  • PuTTY, a Telnet and SSH client for Windows.
  • Telnet help and support.