1. [单选题]某台PC，能ping通路由器，但不能telnet到路由器，可能的原因是（）
A. PC的IP地址设置错误
B. 路由器端口IP设置错误
C. 路由器端口处于关闭状态
D. telnet密码未设置
2. [单选题]路由器上，命令“show int s0”的显示结果为：Serial0 is up,line protocol is down出现该结果的可能原因是（）
A. 端口处于关闭状态
B. 物理端口被烧毁
C. 两端设备协议不一致
D. 路由表中无路由
3. [单选题]Your network uses the172.12.0.0 class B address. You need to support 459 hosts per subnet, while accommodating the maximum number of subnets. Which mask would you use?
A. 255.255.0.0.
B. 255.255.128.0.
C. 255.255.224.0.
D. 255.255.254.0.
E. None of the above
4. [单选题]配置路由器时，封装PPP协议的命令是：()
A. encap ppp
B. ppp
C. group ppp
D. int ppp
5. [单选题]查看E0端口配置信息的命令是：()
A. show access-list
B. show ip route
C. show version
D. show interfacee0
6. [单选题]路由器上“水平分割”的功能是：()
A. 分离端口
B. 阻止路由环路
C. 简化配置
D. 方便故障处理
7. [单选题]The IP network 210.106.14.0 is subnetted using a /24 mask. How many usable networks and host addresses can be obtained from this?
A. 1 network with 254 hosts
B. 4 networks with 128 hosts
C. 2 networks with 24 hosts
D. 6 networks with 64 hosts
E. 8 networks with 36 hosts
8. [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
9. [单选题]During the boot sequence, a Ezonexam 2800 series router needs to locate and load an operating system. What is the default order the router uses to find an operating system?
A. ROM, TFTP server, Flash
B. Flash, TFTP server, ROM
C. Flash, NVRAM, TFTP server
D. Flash, ROM, TFTP server
E. Flash, TFTP server, RAM
10. [单选题]RIP路由协议认为“网络不可到达”的跳数是：()
A. 8
B. 16
C. 24
D. 100
