You wish to increase the security of all of the routers within your network. What can be done to secure the virtual terminal interfaces on a router?

A. Administratively shut down the interface.
B. Physically secure the interface.
C. Create an access list and apply it to the virtual terminal interfaces with the
access-group command.
D. Configure a virtual terminal password and login process.
E. Enter an access list and apply it to the virtual terminal interfaces using the access-class
command.

Answer: D, E


Explanation:
There are a total of 5 logical Virtual terminal interfaces in a Cisco router (lines 0-4) and they are used for remote access into the device via telnet. Configuring these interfaces correctly with a login and password information can be used for security, as each user will be prompted for a password in order to obtain access. A second method is to use the "access-class" command. Combined with an access list, this command can be used to specify the hosts or networks that will be allow access to the device.

Incorrect Answers:
A. Virtual terminal interfaces are logical interfaces that can not be manually shut down.
B. Virtual terminal lines are logical interfaces that reside within a router, so there is nothing that can be physically secured.
C. This command is used with access-lists for LAN and WAN interfaces, but is not used for the VTY lines.