单项选择题
A.It creates a global address pool for all outside NAT transactions
B.It establishes a dynamic address pool for an inside static address
C.It creates dynamic source translations for all inside local PAT transactions
D.It creates a one-to-one mapping between an inside local address and an inside global address
E.It maps one inside source address to a range of outside global addresses
单项选择题 Which command can be a router to verify the layer 3 path to a host？（）
单项选择题 出于安全考虑，网络管理员需要去防止外网主机PING内网，下面哪个协议应该用access control lists限制掉？（）
单项选择题 A company has a small network，consisting of a single switch and a single router. The switch has been configured with two vlans，and route-on-a-stick is being configured on the router for inter-vlan routing. A trunk is configured to connect the switch to the router.What is the minimum number of router subinterfaces that are required for all the vlans to communicate？（）