A. It configures a router to send all packets out interface serial 0/0.
B. It configures a router to block routing updates from being sent out interface serial 0/0.
C. It configures a router as a firewall, blocking all unauthorized packets from exiting serial 0/0.
D. It configures a router to send all packets for unknown destination networks out interface serial 0/0.
E. It configures a router to drop all packets for which the destination network is unknown.

A. It is used to validate the sources of VTP advertisements sent between switches.
B. It is used to access the VTP server to make changes to the VTP configuration.
C. It allows two VTP servers to exist in the same domain, each configured with different passwords.
D. It is the password required when promoting a switch from VTP client mode to VTP server mode.
E. It is used to prevent a switch newly added to the network from sending incorrect VLAN information to the other switches in the domain.