Final answer:
Virtual terminals refer to protocols like Telnet or SSH that provide remote command-line access. SSH, using port 22, is preferred over Telnet, using port 23, due to its secure encryption, making it less susceptible to security threats.
Step-by-step explanation:
In the context of network computing, the term virtual terminals usually refers to virtual terminal protocols like Telnet or Secure Shell (SSH), which are used to gain text-based access to a remote system's command-line interface. Virtual terminal sessions are established through special numbered ports on the server that listen for incoming connections.
For example, Telnet typically uses port 23. This is a non-secure protocol because it transmits data, including passwords, in plain text. On the other hand, SSH, which uses port 22 by default, is a security-oriented protocol that encrypts all the data sent over the connection, making it far less susceptible to eavesdropping or interception.
Given its security advantages, SSH is generally the preferred protocol for remote access. Administrators and users alike prioritize secure communication, which SSH provides, thus making it more favored over Telnet for most purposes.