CCNA题库.docx

1、CCNA题库CCNA题库QUESTION 1Which two features did WPAv1 add to address the inherent weaknesses found in WEP? (Choose two.)A.a stronger encryption algorithmB.key mixing using temporal keysC.shared key authenticationD.a shorter initialization vectorE.per frame sequence countersAnswer: BESection: (none)Expl

2、anation/Reference:QUESTION 2Which two Ethernet fiber-optic modes support distances of greater than 550 meters?A.1000BASE-CXB.100BASE-FXC.1000BASE-ZXD.1000BASE-SXE.1000BASE-LXAnswer: CESection: (none)Explanation/Reference:QUESTION 3What could be possible causes for the “Serial0/0 is down” interface s

3、tatus? (Choose two.)A.a layer 1 problem existsB.the bandwidth is set too lowC.a protocol mismatch existsD.an incorrect cable is being usedE.there is an incorrect IP address on the Serial 0/0 interfaceAnswer: ADSection: (none)Explanation/Reference:QUESTION 4Both switches are using a default configura

4、tion. Which two destination addresses will Host 4 use to send data to Host 1? (Choose two.)A.the IP address of Host 1B.the IP address of Host 4C.the MAC address of Host 1D.the MAC address of Host 4E.the MAC address of the Fa0/0 interface of the R1 routerF.the MAC address of the Fa0/1 interface of th

5、e R1 routerAnswer: AFSection: (none)Explanation/Reference:QUESTION 5What 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 shortes

6、t-path algorithm to the determine best path.D.update the routing table based on updates from their neighbors.E.maintain the topology of the entire network in its database.Answer: ADSection: (none)Explanation/Reference:QUESTION 6What are two characteristics of RIPv2? (Choose two.)A.classful routing p

7、rotocol.B.variable-length subnet masks.C.manual route summarization.D.broadcast addressing.E.uses SPF algorithm to compute path.Answer: BCSection: (none)Explanation/Reference:QUESTION 7What are two characteristics of Frame Relay point-to-point subinterfaces? (Choose two.)A.they require a unique subn

8、et within a routing domain.B.they create split-horizon issues.C.they emulate leased lines.D.they require the use of NBMA options when using OSPF.E.they are ideal for full-mesh topologies.Answer: ACSection: (none)Explanation/Reference:QUESTION 8A wireless client cannot connect to an 802.11b/g BSS wit

9、h a b/g wireless card. The client section of the access point does not list any active WLAN clients. What is a possible reason for this?A.the clients IP address is on the wrong subnet.B.the incorrect channel is configured on the client.C.the SSID is configured incorrectly on the client.D.the client

10、has an incorrect pre-shared key.Answer: CSection: (none)Explanation/Reference:QUESTION 9What occurs on a Frame Relay network when the CIR is exceeded?A.all UDP traffic is marked discard eligible and a BECN is sent.B.all traffic exceeding the CIR is marked discard eligible.C.all TCP traffic is marked

11、 discard eligible and a BECN is sent.D.all TCP traffic is marked discard eligible.Answer: BSection: (none)Explanation/Reference:QUESTION 10A network administrator must configure 200 switch ports to accept traffic from only the currently attached host devices. What would be the most efficient way to

12、configure MAC-level security on all these ports?A.Have end users e-mail their MAC addresses. Telnet to the switch to enter the switchport-port security mac-address command.B.Use the switchport port-security MAC address sticky command on all the switch ports that have end devices connected to them.C.

13、Visually verify the MAC addresses and then telnet to the switches to enter the switchport-port security mac-address command.D.Use show mac-address-table to determine the addresses that are associated with each port and then enter the commands on each switch for MAC address port-security.Answer: BSec

14、tion: (none)Explanation/Reference:QUESTION 11What is the difference between a CSU/DSU and a modem?A.A CSU/DSU converts digital signals from a router to a phone line; a modem converts analog signals from a router to a phone line.B.A CSU/DSU converts digital signals from a router to a leased line; a m

15、odem converts digital signals from a router to a phone line.C.A CSU/DSU converts analog signals from a router to a phone line; a modem converts digital signals from a router to a leased line.D.A CSU/DSU converts analog signals from a router to a leased line; a modem converts analog signalsfrom a rou

16、ter to a leased line.Answer: BSection: (none)Explanation/Reference:QUESTION 12Which three options are valid WAN connectivity methods? (Choose three.)A.L2TPv3B.ATMC.WAPD.PPPE.HDLCAnswer: BDESection: (none)Explanation/Reference:QUESTION 13Which protocols are found in the network layer of the OSI refer

17、ence model and are responsible for path determination and traffic switching?A.WANB.networkC.routingD.LANAnswer: CSection: (none)Explanation/Reference:QUESTION 14Data transfer is slow between the source and destination. The quality of service requested by the transport layer in the OSI reference mode

18、l is not being maintained. To fix this issue, at which layer should the troubleshooting process begin?A.networkB.presentationC.sessionD.physicalE.transportAnswer: ASection: (none)Explanation/Reference:QUESTION 15Which layer in the OSI reference model is responsible for determining the availability o

19、f the receiving program and checking to see if enough resources exist for that communication?A.transportB.presentationC.networkD.sessionE.applicationAnswer: ESection: (none)Explanation/Reference:QUESTION 16A company implements video conferencing over IP on their Ethernet LAN. The users notice that t

20、he network slows down, and the video either stutters or fails completely. What is the most likely reason for this?A.modulationB.packet switching exchange (PSE)C.reliable transport protocol (RTP)D.quality of service (QoS)E.minimum cell rate (MCR)Answer: DSection: (none)Explanation/Reference:QUESTION

21、17What must be set correctly when configuring a serial interface so that higher-level protocols calculate the best route?A.delayB.bandwidthC.loadD.reliabilityAnswer: BSection: (none)Explanation/Reference:QUESTION 18When configuring a serial interface on a router, what is the default encapsulation?A.

22、Frame-relayB.HDLCC.Atm-DxiD.LAPBE.PPPAnswer: BSection: (none)Explanation/Reference:QUESTION 19Which command displays CPU utilization?A.show protocolsB.show processC.show versionD.show systemAnswer: BSection: (none)Explanation/Reference:QUESTION 20Which command is used to debug a ping command?A.debug

23、 tcpB.debug icmpC.debug ip icmpD.debug packetAnswer: CSection: (none)Explanation/Reference:QUESTION 21Which command is used to see the path taken by packets across an IP network?A.show ip routeB.tracerouteC.show routeD.trace ip routeAnswer: BSection: (none)Explanation/Reference:QUESTION 22Which comm

24、and would you configure globally on a Cisco router that would allow you to view directly connected Cisco devices?A.cdp enableB.cdp runC.enable cdpD.run cdpAnswer: BSection: (none)Explanation/Reference:QUESTION 23If IP routing is enabled, which two commands set the gateway of last resort to the defau

25、lt gateway? (Choose two.)A.ip route 0.0.0.0 0.0.0.0 172.16.2.1B.ip default-route 0.0.0.0 0.0.0.0 172.16.2.1C.ip default-network 0.0.0.0D.ip route 172.16.2.1 0.0.0.0 0.0.0.0E.ip default-gateway 0.0.0.0Answer: ACSection: (none)Explanation/Reference:QUESTION 24Which command is used to configure a defau

26、lt route?A.ip route 172.16.1.0 255.255.255.0 0.0.0.0B.ip route 0.0.0.0 0.0.0.0 172.16.2.1C.ip route 0.0.0.0 255.255.255.0 172.16.2.1D.ip route 172.16.1.0 255.255.255.0 172.16.2.1Answer: BSection: (none)Explanation/Reference:QUESTION 25A system administrator types the command to change the hostname o

27、f a router. Where on the Cisco IFS is that change stored?A.NVRAMB.FLASHC.RAMD.ROME.PCMCIAAnswer: CSection: (none)Explanation/Reference:QUESTION 26Which command is used to load a configuration from a TFTP server and merge the configuration into RAM?A.copy TFTP: running-configB.copy running-config: TF

28、TP:C.copy TFTP: startup-configD.copy startup-config: TFTP:Answer: ASection: (none)Explanation/Reference:QUESTION 27Which command is used to copy the configuration from RAM into NVRAM?A.copy startup-config: running-config:B.copy running-config startup-configC.copy startup config running configD.copy

29、running config startup configE.write terminalAnswer: BSection: (none)Explanation/Reference:QUESTION 28Your ISP has given you the address 223.5.14.6/29 to assign to your routers interface. They have also given you the default gateway address of 223.5.14.7. After you have configured the address, the r

30、outer is unable to ping any remote devices. What is preventing the router from pinging remote devices?A.the default gateway is not an address on this subnet.B.the IP address is the broadcast address for this subnet.C.the default gateway is the broadcast address for this subnet.D.the IP address is an