What is vty?

VTY is an acronym for Virtual Teletype. In Cisco IOS-based networking, VTY lines refer to the virtual access points for Telnet and SSH remote connections to a router or switch. The VTY lines are used by network administrators to remotely connect to a device using a command line interface for tasks such as configuration, troubleshooting, and monitoring. A Cisco device typically has up to five VTY lines (0-4) available for remote user connections, and each VTY line allows one user to connect at a time. The VTY line configuration includes settings such as login authentication, privilege levels, idle timeouts, and SSH encryption options.