If you do not configure a vty pass you will not be able to telnet to the switch
vty 0
USb or AUX
Router(config)# line vty 0 4
5
line vty access-class
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
Configure an IP address on the relevant network interface and bring it up. Configure a password on at least on vty line and give the login command.
It will require you to SSH to the router rather than telnet. You will have to use a program like Putty or some other SSH client.
router>enable router#configure terminal router(config)#line vty 0 4 router(config-line)#password cisco router(config-line)#login to configure router with telnet you must set up password or secret for privilieged mode.
The correct answer is:C"The switch Default tp allowing telnet connections only"SOme one gave me the wrong answer but this is the correct one
VTY means -- virtual TTY (teletype)
.to disable the router vty lines