How do you use Telnet or SSH to test and access network devices and servers?

1 What is Telnet?

Telnet is a protocol that enables you to establish a plain-text connection to a network device or server over TCP port 23. Using a Telnet client, such as PuTTY or the command prompt, you can send and receive data from the remote device or server. It is useful for testing basic connectivity and performing simple tasks, such as checking the status of a service or rebooting a device; however, it has several drawbacks. Telnet does not encrypt the data, making it vulnerable to eavesdropping and tampering. Additionally, it does not support authentication, meaning anyone can access the device or server without a username or password. Further, it does not support file transfer, limiting the types of operations you can perform.

2 What is SSH?

SSH is a protocol that enables you to establish a secure and encrypted connection to a network device or server over TCP port 22. You can use an SSH client, such as PuTTY or the command prompt, to send and receive data from the remote device or server. SSH is useful for testing connectivity and performing complex tasks, like configuring settings, executing commands, and transferring files. Compared to Telnet, SSH has several advantages. It encrypts the data so it's protected from eavesdropping and tampering. It also supports authentication which requires a username and password or key pair to access the device or server. Additionally, it supports file transfer which allows you to upload and download files between the local and remote systems.

3 How to use Telnet to test and access network devices and servers?

In order to use Telnet to test and access network devices and servers, you need to install a Telnet client, such as PuTTY or the command prompt, on your local system. Then, open the Telnet client and enter the IP address or hostname of the remote device or server you want to connect to. Press Enter or click Open to initiate the connection. If it is successful, you will see a prompt from the remote device or server, such as > or #. After that, you can type commands and interact with the remote device or server. Finally, type exit or quit and press Enter to close the connection.

4 How to use SSH to test and access network devices and servers?

In order to use SSH to test and access network devices and servers, you must first install an SSH client, such as PuTTY or the command prompt, on your local system. Then open the SSH client and enter the IP address or hostname of the remote device or server you want to connect to. Specify the port number (usually 22) and provide authentication credentials. After pressing Enter or clicking Open, if the connection is successful, you will see a prompt from the remote device or server. You can now type commands and interact with the remote device or server. To close the connection, type exit or logout and press Enter.