Which protocol is used for securely accessing and managing network devices over an unsecured network?

The protocol used for securely accessing and managing network devices over an unsecured network is SSH, or Secure Shell. SSH provides a secure channel over an unsecured network by using encryption to protect the data transmitted between the client and the server. This prevents unauthorized users from eavesdropping or tampering with the communication, which is crucial when managing network devices that may be vulnerable to attacks.

In contrast, other protocols mentioned do not offer the same level of security. FTP (File Transfer Protocol) transmits data in plain text, making it susceptible to interception. HTTP (Hypertext Transfer Protocol) is also insecure for data transmission because it does not encrypt traffic, allowing potential attackers to view sensitive information. Telnet, like FTP and HTTP, is not secure for remote connections because it also sends data, including passwords, in an unencrypted format, exposing it to the risk of interception.

By choosing SSH, users can ensure that their interactions with network devices remain confidential and secure, protecting both the data being transmitted and the devices being managed.