1. [单选题]介质工作在OSI的哪一层（）
A. 物理层
B. 数据链路层
C. 网络层
D. 传输层
2. [单选题]如果把路由器的某个端口的IP配置为：192.168.10.64，掩码配置为：255.255.255.248，则该端口（）
A. 能和其他设备正常通信
B. 会变成“administratively down”状态
C. 端口被烧毁
D. 出现错误提示，配置命令执行失败
3. [单选题]A Ezonexam technician is troubleshooting connectivity problems between two routers that are directly connected through the serial line. The technician notices that the serial line is up but cannot see any neighbors displayed in the output of the show cdp neighbors command.In which OSI layer is the problem most likely occurring?
A. Physical
B. Data link
C. Network layer
D. Transport layer
E. Application layer
4. [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
5. [单选题]为了禁止网络210.93.105.0ftp到网络223.8.151.0，允许其他信息传输，则能实现该功能的选项是：()
A. access-list 1 deny 210.93.105.0.0.0.0.0.0
B. access-list 100 deny tcp 210.93.105.0 0.0.0.255 223.8.151.0 0.0.0.255 eq ftp
C. access-list 100 permit ip any any
D. access-list 100 deny tcp 210.93.105.0 0.0.0.255 223.8.151.00.0.0.255 eq ftp access list 100 permit ip any any
