Which one of the following protocols uses both UDP and TCP ports for the transport layer operation?（）

多项选择题Which of the following protocols utilize UDP as the layer 4 transport mechanism?（）

A.TACACS
B.Telnet
C.SMTP
D.SNMP
E.HTTP
F.TFTP

多项选择题Which of the protocols below use TCP at the transport layer?（）

A.TFTP
B.SMTP
C.SNMP
D.FTP
E.HTTP
F.HTTPS

单项选择题You have just configured a static default route on router TK1. What is the purpose of a default route?（）

A. It is a route to be used when the routing protocol fails.
B. It is a route configured by an ISP that sends traffic into a corporate network.
C. It is a route used when a packet is destined for a remote network that is not listed in the routing table.
D. It is a route manually configured for a specific remote network for which a routing protocol is not configured.
E. It is used to send traffic to a stub network.

多项选择题Some of the TestKing routers have been configured with default routes. What are some of the advantages of using default routes?（）

A. They establish routes that will never go down.
B. The keep routing tables small.
C. They require a great deal of CPU power.
D. The allow connectivity to remote networks that are not in the routing table.
E. They direct traffic from the Internet into corporate networks.

单项选择题How does route poisoning work with holddown timers to prevent routing loops?（）

A. Information learned from one source is not distributed back to that source.
B. Routing updates from the poisoned source are ignored until a holddown timer expires.
C. Failed routes are advertised with infinite metrics.
D. New routing updates are ignored until the network has converged.
E. A route is marked as unavailable when its time-to-live is exceeded.