Virtual teletype definition
Virtual teletype (VTY) is a command line interface that gives users access to a device’s control plane, most often in network devices like routers and switches. By using it, administrators can configure, manage, and monitor the device remotely.
VTY lines are logical interfaces of a device. It means they don’t correspond to a physical port but are created in the device’s software. When a user connects to a device using a remote protocol, for example, SSH or Telnet, the device allocates a VTY line to that session. Each VTY line can accommodate one remote session at a time.
See also: command-line interface
Advantages of using VTY lines
- VTY allows for remote configuration and monitoring of devices, so you don’t need physical access for management tasks.
- Network devices support multiple VTY lines, which allows several administrators to manage the device simultaneously.
- VTY sessions can be secured using authentication and encryption, especially when using protocols like SSH.
Disadvantages of using VTY lines
- The number of VTY lines is finite. Once all lines are occupied, new sessions have to wait.
- If not secured correctly, VTY can be an entry point for cybercriminals. This is a major concern when using older protocols like Telnet, which don’t encrypt data.
- For beginners, CLI and VTY might have a steep learning curve compared to graphical interfaces.