多项选择题
A.They are always present in the NAT table.
B.They allow connection to be initiated from the outside.
C.They can be configured with access lists,to allow two or more connections to be initiated from the outside.
D.They require no inside or outside interface markings because addresses are statically defined.
单项选择题 Which single access list statement will combine all four of these statements into a single statement that will have exactly the same effect（）。
单项选择题 All WAN links inside the ABC University network use PPP with CHAP for authentication security. Which command will display the CHAP authentication process as it occur between two routers in the network?（）
单项选择题 根据下图，网络管理员如此配置的RA的原因是？（）