单项选择题
Which IPsec security protocol should be used when confidentiality is required？（）
A.AH B.MB5 C.PSK D.ESP
多项选择题 Which two subnetworks would be included in the summarized address of 172.31.80.0 /20? （）
单项选择题 Which command can you use to manually assign a static IPV6 address to a router interface？（）
多项选择题 For what two purposes does the Ethernet protocol use physical addresses? （）
