ccna考试题库

1、WORD格式QUESTION 37What are twocharacteristicsof RIPv2? (Choosetwo.)A. classful routingprotocolB. variable-lengthsubnet masksC. broadcast addressingD. manual route summarizationE. uses SPF algorithm tocompute pathAnswer: BDExplanation/Reference:A：有类路由协议，错误B：可变长度子网掩码，正确C：采用播送地址更新，错误D：手动路由汇总，正确E: 使用 spf

2、 算法计算路径，错误。QUESTION 38Which two Ethernet fiber-optic modes support distances of greater than 550 meters? A.1000BASE-CXB. 100BASE-FXC. 1000BASE-LXD. 1000BASE-SX专业资料整理WORD格式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 39What two thin

3、gs will a router do when running adistance vectorrouting protocol? (Choose two.)A. Send periodicupdatesregardless oftopologychanges.B. Send entire routingtableto allrouters intherouting domain.C. Use theshortest-path algorithmto thedetermine best path.D. Update the routingtablebased on updates fromt

4、heir neighbors.E. Maintainthetopologyofthe entirenetworkinits database.Answer: AD专业资料整理WORD格式Explanation/Reference:考点：考察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 commandshows if an access list is assigned to an interface?A. show ip interfac

5、e interface access-listsB. show ip access-lists interface interfaceC. show ip interface interfaceD. show ip access-lists interfaceAnswer: CExplanation/Reference:QUESTION 42Refer to the exhibit. Which rule does the DHCPserveruse when thereisan IP address conflict?专业资料整理WORD格式A. The address is removed

6、 from the pool untilconflict isresolved.B. The address remains in the pool until theconflict is resolved.C. Only the IPdetectedby Gratuitous ARP isremoved from the pool.the专业资料整理WORD格式D. Only the IP detected by Ping is removed from the pool.E. The IP will be shown, even after the conflictis resolved

7、.Answer: AExplanation/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: 地址保存直到冲突解决，错误C/D：答案片面。E：当冲突解决后，地址会被显示。错误。QUESTION 44Refer to the exhibit. If number 2 is selected from the setup script, what happens when the user runs专业资料整理WORD格式setupfrom a privileged promp

8、t?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 will not run, because it is only viablewhen no

9、configuration exists on the router.Answer: AExplanation/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：为有效地重新开场配置，如果路由器是第一次启动的配置。专业资料整理WORD格式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 49Which two statements describe the Cisco implementation of VLANs? (Choose two.) A. VLAN 1 is t

10、he default Ethernet VLAN.B. CDPadvertisements are only sent on VLAN1002. C. By default, the managementVLAN is VLAN1005. D. By default, the switch IP address is in VLAN 1005.E. VLAN 1002 through 1005 are automatically created and cannot be deleted.Answer: AEExplanation/Reference:考点：考察 vlan 知识点。A：缺省都存

11、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，他们都是被保存的特殊 vlan 。专业资料整理WORD格式QUESTION 56没有理解什么意思Refer to the exhibit. What does the (*) represent in the output?A. Packet is de

12、stined 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 destination.Answer: DExplanation/Reference:由图中提示信息可以看出，源

13、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? (Choosethree.)A. VLANsestablishbroadcastdomains in switchednetworks.专业资料整理WORD格式B. VLANs utilizepacket filtering to enhancenetwork security.C. VLANs provide a method of conserving IPaddresses in large networks.D. VLANs provide alo

14、w-latencyinternetworkingalternative to routed networks.E. VLANs allow access tonetwork servicesbasedon department,notphysical location.F. VLANscan greatlysimplifyadding,moving, orchanging hosts on the network.Answer: AEFExplanation/Reference:A：VLAN在交换网络中建立播送域，正确B：利用 VLAN的数据包过滤，增强网络的平安性。错误，没有这个特性。C：提

15、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专业资料整理WORD格式An administratorwould liketo configurea switchover a virtualterminalconnectionfrom locationsoutsideof the local LAN. Which of the following arerequiredin order forthe switcht

16、o be configuredfrom a remotelocation? (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 must be reachable through a port connected to its management VLAN.D. The switch console

17、 port must be connected to the Ethernet LAN.E. The switch managementVLANmust be created and have a membership of at least one switch port.F. The switch must be fully configured as an SNMP agent.Answer: ACExplanation/Reference:要想远程管理 VLAN，1、交换机配置 IP ，2、路由可达专业资料整理WORD格式QUESTION 65Which router IOS comm

18、ands can be used to troubleshoot LAN connectivity problems? (Choose three.)A. pingB. tracertC. ipconfigD. show ip routeE. winipcfgF. show interfaces Answer: ADFExplanation/Reference:A：测试连通性D：查看是否有路由F：查看接口是否可用QUESTION 64Which of the following are benefits of VLANs? (Choose three.)A. They increase the

19、 size of collision domains. B. They allow logical grouping of users by function. 允许用户从逻辑上进展分组专业资料整理WORD格式C. They canenhance network security.D. They increase the size of broadcast domainswhile decreasing the number of collision domains. E. They increase the number of broadcast domainswhile decreasin

20、g the size of the broadcast domains.F. They simplify switch administration.Answer: BCEExplanation/Reference:考察 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：增强网络平安，正确。不同vlan 不能直接通信。D：当减少冲突域时增加播送域的大小。错误E：减少播送域的大小时增加了播送域个数。正确。F: 简化交换机管理。答非所问。QUESTION 71Which characteristics are representative of a link-state rou

21、ting protocol? (Choose three.)A. provides common view of entire topologyB. exchanges routing tables with neighborsC. calculates shortest path专业资料整理WORD格式D. utilizes E. utilizesevent-triggered updates frequent periodic updates专业资料整理WORD格式Answer: ACDExplanation/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。

22、show ip ospf database B：邻居之间交换路由信息，错误。交换 LSAC：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 73Use the output from the router shown in thegraphicabove to determine which of the followingare correct .(Choose two.)专业资料整理WORD格式A. Router John uses a link-state routing protocol.B. Router John willreceiverouti

23、ngupdates on theSerial0/0 interface.C. Router John willreceiveroutingupdates on theSerial0/1 interface.D. Router John willsend routingupdatesouttheSerial0/0 interface.E. Router John willsend routingupdatesoutthe专业资料整理WORD格式FastEthernet0/0 interface.F. Router John willsend routingupdates out theSeria

24、l0/1 interface.Answer: BDExplanation/Reference:由图中几处画红线的地方可知只有s0/0发送和承受路由信息。QUESTION 742的次方问题A national retail chain needs to design an IP addressing schemeto support a nationwide network. Thecompany needs a minimum of 300 sub-networks anda maximum of 50 host addressesper subnet.Working with only on

25、e Class B address, which ofthe following subnet masks will supportanappropriateaddressing scheme ? (Choose two.)A. 255.255.255.0B. 255.255.255.128C. 255.255.252.0D. 255.255.255.224E. 255.255.255.192专业资料整理WORD格式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

26、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 IPF：只有 32 个子网QUESTION 79What information does a router running alink-stateprotocoluse to buildand maintainitstopologicaldatabase? (Choose two.)A. hello packetsB. SAP messages sent by other routersC. LSAs from other routersD. beacons 信息 receivedon point-to-pointli

27、nksE. routingtablesreceivedfrom other link-stateroutersF. TTL packets fromdesignated routersAnswer: AC专业资料整理WORD格式Explanation/Reference:链路状态路由协议如何维护拓扑数据库？A：hello 包用于维护邻居关系，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承受 TTL包，错误，答非所问。QUESTION 80Which statement

28、s describe the routing protocol OSPF? (Choose three.)A. It supports VLSM.B. Itis used to route between autonomous systems .C. Itconfinesnetwork instabilityto one area ofthe network.D. Itincreasesroutingoverhead on the network.E. It allows extensive control of routingupdates .F. It is simpler to conf

29、igure than RIP v2.Answer: ACEExplanation/Reference:专业资料整理WORD格式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X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. bufferingB. cut-throughC. windowingD. congestion avoidan

30、ceE. load balancing Answer: ACD Explanation/Reference:流控制有哪些？A：缓存B：直通C：窗口机制D：拥塞防止E：负载均衡。专业资料整理WORD格式What can be determined from the line of show iprouteoutputshown in the exhibit?(Choose two.)专业资料整理WORD格式注意 R =rip Rout rip Distance 10管理距离修改专业资料整理WORD格式A. The next routing update can be expected in 35

31、 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 distance.E. The 10.10.10.8 network is two hops away fromthis router.Answer: DEExplanation/Reference:专业资料整理WORD格式考点：考察 RIP的路由条目。通过 RIP学习到一条到

32、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 30B：错误，这个 ip 是对端接口 ipC：错误。 s0/1 的ip 无法得知D：正确， rip 缺省的管理距离是 120E：正确。QUESTION 93Refer to the exhibit. From RouterA, a network administrator is able to ping the serial interface of RouterBbut unable to ping any of the subnets atta

33、ched to RouterB. Based on the partial outputs in the exhibit, whatcould be the problem?专业资料整理WORD格式A. EIGRP does not support VLSM.B. The EIGRP network statements areincorrectlyconfigured.C. The IP addressing on the serial interface of RouterA is incorrect.D. The routing protocol has summarized on th

34、e classful boundary.E. EIGRP has been configured with aninvalid专业资料整理WORD格式autonomous system number.Answer: DQUESTION 97For what two purposes does the Ethernet protocol use physical addresses? (Choose two.)A. to uniquely identify devices at Layer 2 B. to allow communication with devices on a differe

35、nt networkC. to differentiate a Layer 2 frame from a Layer 3 packetD. to establish a priority system to determinewhich device gets to transmit firstE. to allow communication between different devices on the same networkF. to allow detection of a remote device when its physical address is unknown Ans

36、wer: AEExplanation/Reference:考点：考察 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，不同网络通信需要通过 IP 地址确定。专业资料整理WORD格式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：当不知道远程设备的物理地址时可以查询，错误。不能跨网段。QUESTION 98As a frame leaves a Layer 3 device, the Layer 2encapsulation information ischanged from what itw

37、aswhen it entered the device.For what two reasonscan this happen? (Choose two.)A. The data is moving from 10BASE-TX to 100BASE-TX.B. The WAN encapsulation type has 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

38、and destinationMACaddresses havechanged.Answer: BEExplanation/Reference:专业资料整理WORD格式考点：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：广域网封装改变，正确。如从HDCL变成 PPPC：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 99Which two statements are trueregardingEIGRP?(Choo

39、se 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. EIGRPsupports VLSM, route summarization, and routing update authentication.C. EIGRPexchanges full routing table information with neighboring routers with every update.D. If the feasi

40、ble successor has a higheradvertised distance than the successor route, it becomes the专业资料整理WORD格式primary route.E. A query process is used to discover a replacement for a failed route if a feasible successor is notidentifiedfrom the currentroutinginformation.Answer: BEExplanation/Reference:A：被动路由在路由

41、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 anappropriateuse of a default route?A. to providerouting to a local web serverB. to provide routingfrom an ISP to a stub networkC. to provide routing that willo

42、verridetheconfigured dynamic routing protocolD. to provideroutingto a destinationthatis notspecifiedin the routing table and which isoutside the local专业资料整理WORD格式networkAnswer: DExplanation/Reference:考点：考察缺省路由的特点A：提供路由到本地 web效劳器，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。根据最长匹配原那么，缺省路由最后才匹配。D：正确QUEST

43、ION 103Refer to the exhibit.A junior network engineerhas preparedthe exhibited configuration file.What twostatementsare trueof the planned configurationfor interface fa0/1? (Choose two.)专业资料整理WORD格式A. The two FastEthernet interfaces will requireNATconfiguredon two outsideserialinterfaces.B. Address

44、translation on fa0/1 is not requiredfor DMZ Devices to access the Internet.C. The fa0/1 IP addressoverlapswith the spaceused by s0/0.D. The fa0/1 IP address isinvalidfor the IPsubnet on which it resides.E. Internethosts maynot initiateconnectionstoDMZ Devices through the configuration that isshown.A

45、nswer: BE专业资料整理WORD格式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 111Refer to the exhibit. Some 2950 series switchesare connected to the conference area of thecorporateheadquarters network . The switchesprovidetwo tothree jacks per conference room to host laptopcon

46、nections foremployees who visit theheadquarters office. When large groups ofemployees come fromotherlocations,thenetwork administratoroftenfindsthathubs have been connected to walljacksin theconferenceareaalthough the portson theaccesslayer switches were notintendedto supportmultipleworkstations.Wha

47、t actioncould thenetwork administratortaketo preventaccess by multiple laptops through asingle专业资料整理WORD格式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 byvisiting employees.B.

48、Configure an ACL to allow only a single MACaddress to connect to the switch at one time.C. Use the mac-address-table 1 globalconfiguration command to limit each port to onesource MACaddress.专业资料整理WORD格式D. Implement Port Securityon allinterfacesanduse the port-securitymaximum1 commandto limitportacce

49、ss to a single MAC address.E. Implement Port Securityon allinterfacesanduse the port-securitymac-address stickycommandtolimit access to a single MAC address. F. Implement Port Security at global configuration mode and use the port-security maximum 1 commandto allow each switch only one attached hub.Answer: DExplanation