1. [单选题]为了使配置私有IP的设备能够访问互联网，应采用的技术是()
A. NAT
B. VLAN
C. ACCESS-LIST
D. DDR
2. [单选题]“ipaccess-group”命令在接口上缺省的应用方向是什么"（）。
A. in
B. 具体取决于接口应用哪个访问控制列表
C. out
D. 无缺省值
3. [单选题]IP地址为：192.168.50.70，掩码为：255.255.255.248，则该IP地址所在子网的子网号为（）
A. 192.168.50.32
B. 192.168.80.64
C. 192.168.50.96
D. 192.168.50.71
4. [单选题]命令“ping127.0.0.1”的功能是（）
A. 测试网卡是否正常
B. 测试网关是否正常
C. 测试TCP/IP协议是否正常
D. 测试介质是否正常
5. [多选题]The Ezonexam network administrator needs to determine what LAN devices to install on the Ezonexam network. What are two advantages of using Layer 2 Ethernet switches over hubs? (Choose two)
A. Allowing simultaneous frame. transmissions
B. Increasing the size of broadcast domains
C. Increasing the maximum length of UTP cabling between devices
D. Filtering frames based on MAC addresses
E. Decreasing the number of collision domains
