Which two of these multicast deployments are most susceptible to attacks from unknown sources?（）

单项选择题What is the default value of the SPT threshold in Cisco routers?（）

A. 0
B. 1
C. 2
D. 4
E. 16
F. infinity

单项选择题To which of these does IP multicast send packets?（）

A. a single host
B. a subset of hosts
C. all hosts sequentially
D. all hosts simultaneously

单项选择题Which of these ports does syslog use to send messages to a syslog server?（）

A.TCP502
B.TCP514
C.TCP520
D.UDP502
E.UDP514
F.UDP520

单项选择题Which of these is a benefit of ESM?（）

A. supports multiple MIBs
B. includesNetFlow, NBAR, and IP SLA software subsystems
C. includesNetFlow, syslog, and IP SLA software subsystems
D. includes a predefined framework for filtering and correlating messages
E. supports two logging processes so output can be sent in standard and ESM format

单项选择题How does ERS use the VLAN tag?（）

A. to provide service internetworking
B. to support transparency for Layer 2 frames
C. as a connection identifier to indicate destination
D. as a mapping to the DLCI in service internetworking
E. to provide a trunk by which all VLANs can navigate from one site to one or multiple sites