思科认证考试CCNA考试模拟题集锦171题及答案

1、思科认证考试（）考试模拟题集锦(1-71题)及答案19及答案1. OxNx During a TFTP transfer using Cisco Routers what is the numeric value, in decimal, of the destination port field of the User Datagram Protocol (UDP) header? a) 96 b) 47 c) a random number above 1024 d) 69 e) none of the above 2. CxNx What is the standard encapsul

2、ation method used by Cisco routers for the Internet Protocol (IP) on its Ethernet interfaces? a) SNAP b) ARPA c) NOVELL-ETHER d) DARPA e) Ethernet_802.3 3. CxNx What will be the correct command on a Cisco router to set the IP address of an interface assuming you are at the "router(config-if)#&q

3、uot; prompt? a) ip address b) ip address c) ip d) ip e) none of the above 4. CxNx Which commands will display the IP addresses of all interfaces on a Cisco Router? (Choose all that apply) a) show ip route b) show ip address c) show ip inter

4、face d) show interface e) display ip addresses 5. CxNx Which of the following commands will display the contents of the ARP cache of your Cisco router? a) show ip arp cache b) show ip route c) show ip arp d) show arp e) there is no way to display the ARP cache 6. CxNx Reverse Address Resolution Prot

5、ocol (RARP) is the process: a) Where an IP host resolves its IP address by broadcasting its MAC address to the network and a BOOTP server assigns it an IP address. b) Where an IP host resolves its MAC address by broadcasting to the local network its IP address. c) Where an IP host tries to resolve t

6、he MAC address of a destination by sending a network broadcast. The destination responds to the broadcast with its MAC address. d) Where an IP host resolves a destination IP address by sending a broadcast on the local network and the destination host responds with its IP address. e)There is no such

7、process. 7. OxNx Which of the following applications requires the connection-oriented layer four protocol, TCP? (Choose all that apply) a) Telnet b) FTP c) TFTP d) SNMP e) none of the above 8. RxNx Which of the following are link state Routing Protocols. (Choose all that apply.) a) IP b) OSPF c) RIP

8、 d) EIGRP e) IS-IS 9. CxNx Of the following commands, identify the correct one for clearing the IP arp table in memory of the router. a) clear ip arp-cache b) clear ip arp-table c) clear arp-cache d) clear arp-table e) clear arp-ram 10. CxNx Which of the following explains the correct definition of

9、administrative distance as it pertains to Ciscos IOS? a) The process by which routers select an administrator for an autonomous system. b) The process where a router will select the best path to a destination network. c) The process where a router will distance itself from other routers due to its l

10、ack of administrative experience. d) The process where a router will prioritize routing protocols so that in the event two routing protocols have conflicting next hop addresses, the routing protocol with the lowest administrative distance will take priority. e) The process where a router will priori

11、tize routing protocols so that in the event two routing protocols have conflicting next hop addresses, the routing protocol with the highest administrative distance will take priority. 11. ExNx Collisions occur when a) multiple packets are placed on a serial link b) multiple stations listen for traf

12、fic and transmit at the same time c) when multiple tokens are on a ring simultaneously d) beaconing process takes place 12. RINx How many subnets are possible with a Class C address and a subnet mask of 52? a) 32 b) 30 c) 60 d) 62 e) 4 13. RxNx What commands will list all protocols that

13、 are currently being routed? (Choose all that apply.) a) show ip protocol b) show protocol c) show run d) show start e) All of the above 14. xxNx Which of the following are true of access lists? a) Access list should have at least one permit statement. b) The last configured line should always be a

14、permit statement. c) Every access-list will implicitly deny all traffic. d) Access-lists are processed top down. e) All of the above. 15. xxNx If the access-group command is configured on an interface and there is no access-list created which of the following is most correct? a) An error message wil

15、l appear. b) The command will be executed and deny all traffic out. c) The command will be executed and permit all traffic out. d) The command will be executed and permit all traffic in and out. e) The command will be executed and deny all traffic in and out. 16. xxNx What is the result of the comma

16、nd? " access-list 101 permit tcp any 55 established" a) telnet sessions will be permitted regardless of the source address b) telnet sessions will be denied regardless of the source address c) telnet sessions will be denied if initiated from any address other than 172.1

17、6.0.0 network d) telnet sessions will be permitted to the network only e) telnet sessions will be denied to the network only 17. xxNx Which is generally true of the location of access-lists? (Choose all that apply.) a) Standard lists will most likely be placed close to the dest

18、ination. b) Standard lists will most likely be placed close to the source. c) Extended lists will most likely be placed close to the destination. d) Extended lists will most likely be placed close to the source. e) It does not matter. 18. RxNx Which of the following is most correct? a) IP is to TCP.

19、 as IPX is to SPX. b) RTMP is to Appletalk as IP RIP is to IP. c) NLSP is to IPX as OSPF is to IP. d) a is true. e) b is true. f) a & b are true. g) c is true. h) b & c are true. i) a, b and c are true. 19. ExNx If Host A sends a packet to Host B over ethernet and Host B is not active: a) Th

20、e packet will time out. b) The packet will be removed by Host A. c) The NVRAM of Host B will remove the packet. d) The packet will "die" when it reaches the terminator. e) The packet will be removed by the token monitor. Coding Key and Information The first character represents the categor

21、y of question. A - ATM B - Bridging C - Cisco specific E - Ethernet F - Frame relay H - HDLC I - FDDI N - ISDN O - OSI model P - PPP R - Routing S - Switching T - Token ring X - X.25 x - Not applicable The second character represents protocol. A - Appletalk B - Banyan Vines D - Decnet I - IP L - Dia

22、l on Demand N - NLSP O - OSPF X - IPX x - Not Applicable The third character represents the certification that the question will help you prepare for. N - CCNA Exam #640-407 P - CCNP Advanced Cisco Router Configuration (ACRC) Exam 640-403 Cisco LAN Switch Configuration (CLSC) Exam #640-404 Cisco Mon

23、itoring and Troubleshooting Dial-up Services Exam #640-405 Cisco Internetworking Troubleshooting ( CIT) Exam #640-406D - CCDA & CCDP Cisco Design Specialist Exam #9E0-004 Cisco Internetwork Design#640-025We will reserve the fourth character for future use. As an example, when you come across a q

24、uestion coded "BXDx", it signifies a question that will help you gain the CCDA or CCDP certification. CCNA试题1-19答案1. OxNx During a TFTP transfer using Cisco Routers what is the numeric value, in decimal, of the destination port field of the User Datagram Protocol (UDP) header? a) 96 b) 47

25、c) a random number above 1024 d) 69 e) none of the above Answer d) 69 Here is a sampling of other port numbers and the application they are associated with. The first 8 of these protocols are automatically forwarded through the router by using the helper-address command Trivial File Transfer (TFTP)

26、(port 69) Domain Name System (port 53) IEN-116 Name Server (port 42) Time service (port 37) NetBIOS Name Server (port 137) NetBIOS Datagram Server (port 138) Boot Protocol (BootP) client and server datagrams (port 67) TACACS service (port 49) Simple Mail Transfer Protocol (25) File Transfer Protocol

27、 (21) Simple Network Management Protocol (161)  2. CxNx What is the standard encapsulation method used by Cisco routers for the Internet Protocol (IP) on its Ethernet interfaces? a) SNAP b) ARPA c) NOVELL-ETHER d) DARPA e) Ethernet_802.3 Answer b) ARPA SNAP is the default encapsulation for a to

28、ken ring interface NOVELL-ETHER is the default encapsulation for a ipx interface.  3. CxNx What will be the correct command on a Cisco router to set the IP address of an interface assuming you are at the "router(config-if)#" prompt? a) ip address b) ip address 1.

29、1.1.1 c) ip d) ip e) none of the above Answer a) ip address If you are not in the configuration mode, the ip address can be set by using the setup mode. Configuring interface Ethernet0/0: Is this interface in use? yes: Configure IP on this interfac

30、e? yes: IP address for this interface : Number of bits in subnet field 16: 16 Class A network is , 16 subnet bits; mask is /24 Take note when using the setup mode the mask is configured using the number of subnet bits.  4. CxNx Which commands will display the IP add

31、resses of all interfaces on a Cisco Router? (Choose all that apply) a) show ip route b) show ip address c) show ip interface d) show interface e) display ip addresses Answer c) show ip interface d) show interface Examples of each of these commands are shown below: Router_A#sh int e0/0Ethernet0/0 is

32、up, line protocol is upHardware is AmdP2, address is (bia 0010.7b15.bd41)MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255Encapsulation ARPA, loopback not set, keepalive set (10 sec)ARP type: ARPA, ARP Timeout 04:00:00Last input never, output 00:00:06, output hang neverLast clea

33、ring of "show interface" counters neverQueueing strategy: fifoOutput queue 0/40, 0 drops; input queue 0/75,0 drops5 minute input rate 0 bits/sec, 0 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec0 packets input, 0 bytes, 0 no bufferReceived 0 broadcasts, 0 runts, 0 giants,0 throt

34、tles, 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort0 input packets with dribble condition detected127 packets output, 11802 bytes, 0 underruns0 output errors, 0 collisions, 2 interface resets0 babbles, 0 late collision, 0 deferred0 lost carrier, 0 no carrier0 output buffer failures,

35、0 output buffers swapped outRouter_A#sh ip int e0/0Ethernet0/0 is up, line protocol is upAddress determined by non-volatile memoryMTU is 1500 bytesHelper address is not setDirected broadcast forwarding is enabledOutgoing access list is not setInbound access list is not setProxy ARP is enabledSecurit

36、y level is defaultSplit horizon is enabledICMP redirects are always sentICMP unreachables are always sentICMP mask replies are never sentIP fast switching is enabledIP fast switching on the same interface is disabledIP multicast fast switching is enabledRouter Discovery is disabledIP output packet a

37、ccounting is disabledIP access violation accounting is disabledTCP/IP header compression is disabledProbe proxy name replies are disabledGateway Discovery is disabledPolicy routing is disabledNetwork address translation is disabled5. CxNx Which of the following commands will display the contents of

38、the ARP cache of your Cisco router? a) show ip arp cache b) show ip route c) show ip arp d) show arp e) there is no way to display the ARP cache Answer c) show ip arp Example: Router_A#sh ip arp Protocol Address Age(min) Hardware Address Type Interface Internet - 0010.7b15.bd50 ARPA FastEthe

39、rnet1/0 Internet - 0010.7b15.bd41 ARPA Ethernet0/0  6. CxNx Reverse Address Resolution Protocol (RARP) is the process: a) Where an IP host resolves its IP address by broadcasting its MAC address to the network and a BOOTP server assigns it an IP address. b) Where an IP host resolves

40、its MAC address by broadcasting to the local network its IP address. c) Where an IP host tries to resolve the MAC address of a destination by sending a network broadcast. The destination responds to the broadcast with its MAC address. d) Where an IP host resolves a destination IP address by sending

41、a broadcast on the local network and the destination host responds with its IP address. e)There is no such process. Answer a) Where an IP host resolves its IP address by broadcasting its MAC address to the network and a BOOTP server assigns it an IP address. Choice C describes Address Resolution Pro

42、tocol (ARP). A host never has to resolve its own MAC address. The MAC address is burned into the Network Interface card. When the host is booted the MAC address will be loaded into memory.  7. OxNx Which of the following applications requires the connection-oriented layer four protocol, TCP? (C

43、hoose all that apply) a) Telnet b) FTP c) TFTP d) SNMP e) none of the above Answer a) Telnet b) FTP TFTP and SNMP use layer 4 UDP.  8. RxNx Which of the following are link state Routing Protocols. (Choose all that apply.) a) IP b) OSPF c) RIP d) EIGRP e) IS-IS Answer b) OSPF e) IS-IS A link sta

44、te routing protocol advertises, to its neighbors, the state of the link when the state of the link changes. A distance vector routing protocol advertises its routing table periodically.  9. CxNx Of the following commands, identify the correct one for clearing the IP arp table in memory of the r

45、outer. a) clear ip arp-cache b) clear ip arp-table c) clear arp-cache d) clear arp-table e) clear arp-ram Answer c) clear arp-cache If you have changed an ip address or a NIC card on a host you might use this command to reset the cache.  10. CxNx Which of the following explains the correct defi

46、nition of administrative distance as it pertains to Ciscos IOS? a) The process by which routers select an administrator for an autonomous system. b) The process where a router will select the best path to a destination network. c) The process where a router will distance itself from other routers du

47、e to its lack of administrative experience. d) The process where a router will prioritize routing protocols so that in the event two routing protocols have conflicting next hop addresses, the routing protocol with the lowest administrative distance will take priority. e) The process where a router w

48、ill prioritize routing protocols so that in the event two routing protocols have conflicting next hop addresses, the routing protocol with the highest administrative distance will take priority. Answer d) The process where a router will prioritize routing protocols so that in the event two routing p

49、rotocols have conflicting next hop addresses, the routing protocol with the lowest administrative distance will take priority. Cisco uses administrative distances (AD) to measure the reliability of the routing protocol. The lower the (AD) the more reliable the protocol. Router_C#sh ip routeCodes: C

50、- connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGPi - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, *

51、 - candidate defaultU - per-user static route, o - ODRGateway of last resort is not set/24 is subnetted, 2 subnetsC is directly connected, Serial1C is directly connected, Serial0I /8 100/8576 via , 00:00:09, Serial1100/8576 via , 00:00:19,

52、Serial0The 100 in bold is the administrative distance for IGRP.A partial list of administrative distances is included below:Protocol ADEIGRP 90IGRP 100 OSPF 110RIP 120BGP 180If a router hears a IP RIP and a IGRP update for the same network the router will discard the rip information. IP RIP uses hop

53、 count as its metric, while IGRP uses a composite metric including bandwidth and load, speed is the primary consideration.  11. ExNx Collisions occur when a) multiple packets are placed on a serial link b) multiple stations listen for traffic and transmit at the same time c) when multiple token

54、s are on a ring simultaneously d) beaconing process takes place Answer b) multiple stations listen for traffic and transmit at the same time Collisions is a term that is used in an ethernet environment. Ethernet can be described as a listen then transmit scenario. First a station will listen for tra

55、ffic if no traffic is sensed then a transmission will take place. If two stations transmit at the same time collisions will occur. The first station to detect the collision sends out a jamming signal to alert all stations a collision has occurred. At this point these stations set up a random interva

56、l timer when the timer expires re-transmission will occur. Token ring is a token passing process a station can transmit only when he has the token. There never can be multiple tokens on the ring. Early token release allows up to two data frames to be transmitted on a token ring LAN at the same time.

57、 Collisions do not occur on a token ring. Because of the point to point nature of serial links collisions do not occur. Beaconing is a term used in a token passing environment.  12. RINx How many subnets are possible with a Class C address and a subnet mask of 52? a) 32 b) 30 c) 60 d) 62 e) 4 Answer d) 62 The above mask is using 6 bits to describe subnets. The formula used to determin