ccna考试题库

1、QUESTION 37What are two characteristics of RIPv2? (Choose two.) A. classful routing protocol B. variable-length subnet masks C. broadcast addressing D. manual route summarization E. uses SPF algorithm to compute path Answer: BD Explanation/Reference: A：有类路由协议，错误 B：可变长度子网掩码，正确 C：采用广播地址更新，错误 D：手动路由汇总，

2、正确 E:使用 spf 算法计算路径，错误。 QUESTION 38 Which two Ethernet fiber-optic modes support distances of greater than 550 meters? A.1000BASE-CX B. 100BASE-FX C. 1000BASE-LX D. 1000BASE-SX E. 1000BASE-ZX Answer: CE Explanation/Reference: A：最长距离 25 米 B：最长距离 100 米 C：最长距离 3000 米 D：最长距离 550 米 E：最长距离 70 千米 QUESTION 3

3、9 What two things will a router do when running a distance vector routing protocol? (Choose two.) A. Send periodic updates regardless of topology changes. B. Send entire routing table to all routers in the routing domain. C. Use the shortest-path algorithm to the determine best path. D. Update the r

4、outing table based on updates from their neighbors. E. Maintain the topology of the entire network in its database. Answer: AD Explanation/Reference: 考点：考查距离矢量路由协议特性 A：周期性更新，正确 B：发送整个路由表到整个路由域，错误，只发送给邻居 C：使用 SPF 算法，错误 D：依靠邻居发送更新来更新路由表，正确 E：在数据库中维护整个网络的拓扑。错误 Which command shows if an access list is a

5、ssigned to an interface? A. show ip interface interface access-lists B. show ip access-lists interface interface C. show ip interface interface D. show ip access-lists interface Answer: C Explanation/Reference: QUESTION 42 Refer to the exhibit. Which rule does the DHCP server use when there is an IP

6、 address conflict? A. The address is removed from the pool until the conflict is resolved. B. The address remains in the pool until the conflict is resolved. C. Only the IP detected by Gratuitous ARP is removed from the pool. D. Only the IP detected by Ping is removed from the pool. E. The IP will b

7、e shown, even after the conflict is resolved. Answer: A Explanation/Reference: show ip dhcp conflict 命令可以查看哪些 ip 地址在使用上有冲突。 有冲突的地址不再分配出去。 A：地址被删除直到冲突解决，正确 B:地址保留直到冲突解决，错误 C/D：答案片面。 E：当冲突解决后，地址会被显示。错误。 QUESTION 44 Refer to the exhibit. If number 2 is selected from runs user the when happens what scri

8、pt, setup the setup from a privileged prompt? A. Setup is additive and any changes will be added to the config script. B. Setup effectively starts the configuration over as if the router was booted for the first time. C. Setup will not run if an enable secret password exists on the router. D. Setup

9、will not run, because it is only viable when no configuration exists on the router. Answer: A Explanation/Reference: 0不保存进入 IOS 命令配置模式 1不保存返回设置模式 2保存退出 A：设置和改动被保存到配置脚本 B：为有效地重新开始配置，如果路由器是第一次启动 的配置。 C：如果配置了密码，设置不会运行 D：设置不可用，因为它只能在没有配置存在时才有效 QUESTION 49 Which two statements describe the Cisco implemen

10、tation of VLANs? (Choose two.) A. VLAN 1 is the default Ethernet VLAN. B. CDP advertisements are only sent on VLAN 1002. C. By default, the management VLAN is VLAN 1005. D. By default, the switch IP address is in VLAN 1005. E. VLAN 1002 through 1005 are automatically created and cannot be deleted. A

11、nswer: AE Explanation/Reference: 考点：考查 vlan 知识点。 A：缺省都存在 vlan1，端口都属于 vlan1，正确 B：CDP 信息只发送到 vlan1002，错误，vlan1002是 fddi 网络的 vlan 号。 C：缺省情况交换机 IP 配置在 vlan1005，错误，vlan1005trnet 网络的 vlan 号。缺省在 vlan1 里面。 D：vlan1002-1005 自动生成并不能被删除，正确，他 。vlan 们都是被保留的特殊QUESTION 56 没有理解什么意思 Refer to the exhibit. What does th

12、e (*) represent in the output? A. Packet is destined for a local interface to the router. B. Packet was translated, but no response was received from the distant device. C. Packet was not translated, because no additional ports are available. D. Packet was translated and fast switched to the destina

13、tion. Answer: D Explanation/Reference: 由图中提示信息可以看出，源为 10.10.0.2 已经有个一个转换，所以后续的数据包快速转发。 What are three advantages of VLANs? (Choose three.) A. VLANs establish broadcast domains in switched networks. B. VLANs utilize packet filtering to enhance network security. C. VLANs provide a method of conserving

14、 IP addresses in large networks. D. VLANs provide a low-latency internetworking alternative to routed networks. E. VLANs allow access to network services based on department, not physical location. F. VLANs can greatly simplify adding, moving, or changing hosts on the network. Answer: AEF Explanatio

15、n/Reference: A：VLAN 在交换网络中建立广播域，正确 B：利用 VLAN 的数据包过滤，增强网络的安全性。错误，没有这个特性。 C：提供了在大型网络中的保护 IP 地址的方法。错误 D：提供低延迟互联网络替代路由网络。错误 E：vlan 允许基于逻辑划分的网络访问，不是物理位置。正确。 F：VLAN 可以大大简化添加，移动或更改网络上的主机。正确。 QUESTION 61 An administrator would like to configure a switch over a virtual terminal connection from locations outs

16、ide of the local LAN. Which of the following are required in order for the switch to be configured from a remote location? (Choose two.) A. The switch must be configured with an IP address, subnet mask, and default gateway. B. The switch must be connected to a router over a VLAN trunk. C. The switch

17、 must be reachable through a port connected to its management VLAN. D. The switch console port must be connected to the Ethernet LAN. E. The switch management VLAN must be created and have a membership of at least one switch port. F. The switch must be fully configured as an SNMP agent. Answer: AC E

18、xplanation/Reference: 、路由可达 2，IP、交换机配置 1，VLAN 要想远程管理QUESTION 65 Which router IOS commands can be used to troubleshoot LAN connectivity problems? (Choose three.) A. ping B. tracert C. ipconfig D. show ip route E. winipcfg F. show interfaces Answer: ADF Explanation/Reference: A：测试连通性 D：查看是否有路由 F：查看接口是

19、否可用 QUESTION 64 Which of the following are benefits of VLANs? (Choose three.) A. They increase the size of collision domains. B. They allow logical grouping of users by 允许用户从逻辑上进行分组 function.C. They can enhance network security. D. They increase the size of broadcast domains while decreasing the num

20、ber of collision domains. E. They increase the number of broadcast domains while decreasing the size of the broadcast domains. F. They simplify switch administration. Answer: BCE Explanation/Reference: 考查 VLAN 的特点 A：增加冲突域的大小，错误 B：允许逻辑划分网段，正确 C：增强网络安全，正确。不同 vlan 不能直接通信。 D：当减少冲突域时增加广播域的大小。错误 E：减少广播域的大

21、小时增加了广播域个数。正确。 F:简化交换机管理。答非所问。 QUESTION 71 Which characteristics are representative of a link-state routing protocol? (Choose three.) A. provides common view of entire topology B. exchanges routing tables with neighbors C. calculates shortest path D. utilizes event-triggered updates E. utilizes freq

22、uent periodic updates Answer: ACD Explanation/Reference: 链路状态路由协议有协议特点？ A:提供查看拓扑的命令，正确。show ip ospf database B：邻居之间交换路由信息，错误。交换 LSA C：计算最短路径，正确。 D：利用触发更新，正确 E：利用周期更新，错误。 QUESTION 73 Use the output from the router shown in the graphic above to determine which of the following are correct. (Choose two

23、.) A. Router John uses a link-state routing protocol. B. Router John will receive routing updates on the Serial0/0 interface. C. Router John will receive routing updates on the Serial0/1 interface. D. Router John will send routing updates out the Serial0/0 interface. E. Router John will send routing

24、 updates out the FastEthernet0/0 interface. F. Router John will send routing updates out the Serial0/1 interface. Answer: BD Explanation/Reference: 由图中几处画红线的地方可知只有 s0/0 发送和接受路由信息。 QUESTION 74 2 的次方问题 A national retail chain needs to design an IP addressing scheme to support a nationwide network. The

25、 company needs a minimum of 300 sub-networks and a maximum of 50 host addresses per subnet. Working with only one Class B address, which of the following subnet masks will support an appropriate addressing scheme? (Choose two.) A. 255.255.255.0 B. 255.255.255.128 C. 255.255.252.0 D. 255.255.255.224

26、E. 255.255.255.192 F. 255.255.248.0 Answer: BE Explanation/Reference: 需要至少 300 个子网，每个子网至少 50 台主机。使用一个 B 类地址来划分。 A：最多有 256 个子网，错误 C：只有 64 个子网 D：每个子网只有 30 个可用 IP F：只有 32 个子网 QUESTION 79 What information does a router running a link-state protocol use to build and maintain its topological database? (Ch

27、oose two.) A. hello packets B. SAP messages sent by other routers C. LSAs from other routers D. beacons 信息 received on point-to-point links E. routing tables received from other link-state routers F. TTL packets from designated routers Answer: AC Explanation/Reference: 链路状态路由协议如何维护拓扑数据库？ A：hello 包用于

28、维护邻居关系，正确。 B：错误，没有这个概念。 C：通过其他路由器的 LSA，正确。 D：从点到点链路接收，错误。答案片面 E：从其他路由器接收路由表，错误。相互间不直接发送路由表。 F：从 DR 接受 TTL 包，错误，答非所问。 QUESTION 80 Which statements describe the routing protocol OSPF? (Choose three.) A. It supports VLSM. B. It is used to route between autonomous systems. C. It confines network instabi

29、lity to one area of the network. D. It increases routing overhead on the network. E. It allows extensive control of routing updates. F. It is simpler to configure than RIP v2. Answer: ACE Explanation/Reference: A：支持 VLSM，正确 B：在 AS 之间使用，错误。在 AS 内部使用 C：限制了不稳定网络的范围，正确。通过划分区域实现。 D：增加了网络的开销，错误。 E：允许路由更新控

30、制，正确。 F：比 RIPv2 更容易配置，错误，答非所问。 Which of the following are types of flow control? (Choose three.) A. buffering B. cut-through C. windowing D. congestion avoidance E. load balancing Answer: ACD Explanation/Reference: 流控制有哪些？ A：缓存 B：直通 C：窗口机制 D：拥塞避免 ：负载均衡。EWhat can be determined from the line of show i

31、p route output shown in the exhibit? (Choose two.) 注意 R =rip 管理距离修改 Rout rip Distance 10 A. The next routing update can be expected in 35 seconds. B. The IP address 10.10.10.6 is configured on S0/1. C. The IP address 10.10.10.8 is configured on S0/1. D. This route is using the default administrative

32、 distance. E. The 10.10.10.8 network is two hops away from this router. Answer: DE Explanation/Reference: 考点：考查 RIP 的路由条目。通过 RIP 学习到一条到达 10.10.10.8 的路由，下一跳是10.10.10.6，出接口是 s/1。 A：错误。rip 更新周期为 30s，正常计时器不会超过 30 B：错误，这个 ip 是对端接口 ip C：错误。s0/1 的 ip 无法得知 D：正确，rip 缺省的管理距离是 120 E：正确。 QUESTION 93 Refer to th

33、e exhibit. From RouterA, a network administrator is able to ping the serial interface of RouterB but unable to ping any of the subnets attached to RouterB. Based on the partial outputs in the exhibit, what could be the problem? A. EIGRP does not support VLSM. B. The EIGRP network statements are inco

34、rrectly configured. C. The IP addressing on the serial interface of RouterA is incorrect. D. The routing protocol has summarized on the classful boundary. invalid E. EIGRP has been configured with anautonomous system number. Answer: D QUESTION 97 For what two purposes does the Ethernet protocol use

35、physical addresses? (Choose two.) A. to uniquely identify devices at Layer 2 B. to allow communication with devices on a different network C. to differentiate a Layer 2 frame from a Layer 3 packet D. to establish a priority system to determine which device gets to transmit first E. to allow communic

36、ation between different devices on the same network F. to allow detection of a remote device when its physical address is unknown Answer: AE Explanation/Reference: 考点：考查 mac 地址的作用。 A：在二层唯一确定一台设备，正确 B：是设备在不同的网络中通信，错误，不同网络通信 地址确定。IP 需要通过C：区别二层和三层帧，错误。 D：确定设备的优先级，错误。没有这个功能。 E：是同一网络的不同设备可以通信，正确 F：当不知道远程

37、设备的物理地址时可以查询，错误。不能跨网段。 QUESTION 98 As a frame leaves a Layer 3 device, the Layer 2 encapsulation information is changed from what it was when it entered the device. For what two reasons can this happen? (Choose two.) A. The data is moving from 10BASE-TX to 100BASE-TX. B. The WAN encapsulation type h

38、as changed. C. The data format has changed from analog to digital. D. The source and destination hosts are in the same subnet. E. The source and destination MAC addresses have changed. Answer: BE Explanation/Reference: 考点：数据包转发过程。当数据包离开三层设备时，二层封装哪些信息改变了。 A：从 10M 网络到 100M 网络，错误。带宽改变不会改变数据包封装。 B：广域网封装

39、改变，正确。如从 HDCL 变成 PPP C：数据格式从模拟型号变成数据信号，错误，物理层的信号方式变化不会影响二层数据格式。 D：错误。 E：原蜜 MAC 改变，正确。 QUESTION 99 Which two statements are true regarding EIGRP? (Choose two.) A. Passive routes 简单的说就是：能被路由器路由的协议。例如：IP、IPX、APPLE TALK 等 are in the process of being calculated by DUAL. B. EIGRP supports VLSM, route summ

40、arization, and routing update authentication. C. EIGRP exchanges full routing table information with neighboring routers with every update. D. If the feasible successor has a higher advertised distance than the successor route, it becomes the primary route. E. A query process is used to discover a r

41、eplacement for a failed route if a feasible successor is not identified from the current routing information. Answer: BE Explanation/Reference: A：被动路由在路由进程中由 dual 计算，错误。 B：至此 VLSM，路由汇总，认证，正确 C：每次更新都发送全部的路由信息，错误，增量更新。 D：如果可行后继路由器有一个比后继路由器高的通告距离，它会成为主路由条目，错误。 E：如果不存在 FS，使用查询进程去发现替代失效的路由信息，正确。 What is

42、an appropriate use of a default route? A. to provide routing to a local web server B. to provide routing from an ISP to a stub network C. to provide routing that will override the configured dynamic routing protocol D. to provide routing to a destination that is not specified in the routing table an

43、d which is outside the local network Answer: D Explanation/Reference: 考点：考查缺省路由的特点 A：提供路由到本地 web 服务器，错误 B：提供从 ISP 到末节网络的路由，错误 C：提供优先于动态路由协议的路由，错误。根据最长匹配原则，缺省路由最后才匹配。 D：正确 QUESTION 103 Refer to the exhibit. A junior network engineer has prepared the exhibited configuration file. What two statements a

44、re true of the planned configuration for interface fa0/1? (Choose two.) A. The two FastEthernet interfaces will require NAT configured on two outside serial interfaces. B. Address translation on fa0/1 is not required for DMZ Devices to access the Internet. C. The fa0/1 IP address overlaps with the s

45、pace used by s0/0. D. The fa0/1 IP address is invalid for the IP subnet on which it resides. E. Internet hosts may not initiate connections to DMZ Devices through the configuration that is shown. Answer: BE Explanation/Reference: DMZ 使用公网地址，不需要做 NAT，图中 ACL 第二条错将 DMZ 做了 NAT，因此造成不能访问 QUESTION 111 Refe

46、r to the exhibit. Some 2950 series switches are connected to the conference area of the corporate headquarters network. The switches provide two to three jacks per conference room to host laptop connections for employees who visit the headquarters office. When large groups of employees come from oth

47、er locations, the network administrator often finds that hubs have been connected to wall jacks in the conference area although the ports on the access layer switches were not intended to support multiple workstations. What action could the network administrator take to prevent access by multiple la

48、ptops through a single switch port and still leave the switch functional for its intended use? A. Configure static entries in the switch MAC address table to include the range of addresses used by visiting employees. B. Configure an ACL to allow only a single MAC address to connect to the switch at

49、one time. C. Use the mac-address-table 1 global configuration command to limit each port to one source MAC address. D. Implement Port Security on all interfaces and use the port-security maximum 1 command to limit port access to a single MAC address. E. Implement Port Security on all interfaces and

50、use the port-security mac-address sticky command to limit access to a single MAC address. F. Implement Port Security at global configuration mode and use the port-security maximum 1 command to allow each switch only one attached hub. Answer: D Explanation/Reference: 考点：考查交换机端口安全。题目想实现限制一个端口只接入一台设备。

51、A：配置静态 mac 地址表。错误。无法达到限制效果。 B：配置 ACL 允许同一个时刻仅一个 mac 地址连接到交换机。错误。 C：在全局配置模式使用 mac-address-table 命令限制每个端口一个源 mac 地址。错误，无法实现。 限制一 1maximum 和 securityport 在所有端口使用：D个端口允许一个 mac 地址，正确。 E：部署 port security 和 port-security mac-address sticky 命令，错误，无法实现。 F：在所有端口使用 port security 和 maximum 1限制一个端口允许一个 hub，错误，一个 hub 下面可以接多台 PC。 Running both IPv4 and IPv6 on a router simultaneously is known as what? A. 4to6 routing B. 6to4 routing C. binary routing D. dual-stack routing E. NextGen routing Answer: D Explanation/Reference: 考点：考查 IPv4