Router(config)# line vty 0 4
On user exec mode type enable.When you are on the privilege mode type configure terminal.Upon reaching global config mode you have to type line vty 0 4.Inside the vty line mode type password Please see below example:Router>enableRouter#configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)#line vty 0 4Router(config-line)#password secretRouter(config-line)#exitRouter(config)#exit
telnet
line vty access-class
Type on previllage Mode:- Router(config)#line vty 0 4 Router(config-line)#pass Router(config-line)#password 123 Router(config-line)#login Router(config-line)#exit used for telnet , to take ur PC on telnet through Router..............
router(config-line)#access-class 102 in
VTY means -- virtual TTY (teletype)
router(config)#line vty 0 4router(config-line)#transport input ssh
If you do not configure a vty pass you will not be able to telnet to the switch
RTRA(config)# line vty 0 4 RTRA(config-line)# login RTRA(config-line)# password cisco
Virtual teletype (VTY) is a command line interface (CLI) created in a router and used to facilitate a connection to the daemon via Telnet, a network protocol used in local area networks.To connect to a VTY, users must present a valid password.The VTY interface has three restricted mode commands:VTY View: Enables read-only interface accessVTY Enable: Enables read-write access to the CLIVTY Other: Includes modes like Trivial File Transfer Protocol (TFTP)VTY uses a set of CLI command actions, which depend on the three types of actions CLI can perform:MovementEditingAdvanced
line vty