1. [单选题]Which of the following statements about internet is (are) correct?Ⅰ.Each host in internet only has a IP address.
A. Ⅱ.It is possible to have multiple names corresponding to the same IP address.
B. Ⅲ.In users' points, Internet means a virtual network.
C. None
D. Ⅰ and Ⅱ
E. Ⅱ and Ⅲ
F. All
2. [单选题]Cisco PIX 525防火墙用于实现内部地址和外部地址吲定映射的配置命令是______。
A. nat
B. static
C. global
D. fixup
3. [单选题]存储器映象编址，也称为统一编址，其特点是
A. 有专用的I/O指令
B. 无专用的I/O指令
C. I/O译码电路简单
D. 执行I/O读操作时间较短
