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思科认证考试(CCNA)考试模拟题集锦(1-71题)及答案

思科认证考试（ＣＣＮＡ）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) 96b) 47c) a random number above 1024d) 69e) none of the above2. [CxNx] What is the standard encapsulation method used by Cisco routers for the Internet Protocol (IP) on it’s Ethernet interfaces?a) SNAPb) ARPAc) NOVELL-ETHERd) DARPAe) Ethernet_802.33. [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 1.1.1.1 255.255.255.0b) ip address 1.1.1.1c) ip 1.1.1.1d) ip 1.1.1.1 255.255.255.0e) none of the above4. [CxNx] Which commands will display the IP addresses of all interfaces on a Cisco Router? (Choose all that apply)a) show ip routeb) show ip addressc) show ip interfaced) show interfacee) display ip addresses5. [CxNx] Which of the following commands will display the contents of the ARP cache of your Cisco router?a) show ip arp cacheb) show ip routec) show ip arpd) show arpe) there is no way to display the ARP cache6. [CxNx] Reverse Address Resolution Protocol (RARP) is the process:a) Where an I P host resolves it’s IP address by broadcasting it’s MAC address to the network and a BOOTP server assigns it an IP address.b) Where an IP host resolves it’s MAC address by broadcasting to the local network it’s 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 it’s 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 it’s IP address.e)There is no such process.7. [OxNx] Which of the following applications requires the connection-oriented layer four protocol, TCP? (Choose all that apply)a) Telnetb) FTPc) TFTPd) SNMPe) none of the above8. [RxNx] Which of the following are link state Routing Protocols.(Choose all that apply.)a) IPb) OSPFc) RIPd) EIGRPe) IS-IS9. [CxNx] Of the following commands, identify the correct one for clearing the IP arp table in memory of the router.a) clear ip arp-cacheb) clear ip arp-tablec) clear arp-cached) clear arp-tablee) clear arp-ram10. [CxNx] Which of the following explains the correct definition of administrative distance as it pertains to Cisco’s 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 it’s 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 will 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.11. [ExNx] Collisions occur whena) multiple packets are placed on a serial linkb) multiple stations listen for traffic and transmit at the same timec) when multiple tokens are on a ring simultaneouslyd) beaconing process takes place12. [RINx] How many subnets are possible with a Class C address and a subnet mask of 255.255.255.252?a) 32b) 30c) 60d) 62e) 413. [RxNx] What commands will list all protocols that are currently being routed? (Choose all that apply.)a) show ip protocolb) show protocolc) show rund) show starte) All of the above14. [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 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 will 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 command?" access-list 101 permit tcp any 172.16.0.0 0.0.255.255 established"a) telnet sessions will be permitted regardless of the source addressb) telnet sessions will be denied regardless of the source addressc) telnet sessions will be denied if initiated from any address other than 172.16.0.0 networkd) telnet sessions will be permitted to the 172.16.0.0 network onlye) telnet sessions will be denied to the 172.16.0.0 network only17. [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 destination.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. 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) The 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 InformationThe first character represents the category of question.A - ATMB - BridgingC - Cisco specificE - EthernetF - Frame relayH - HDLCI - FDDIN - ISDNO - OSI modelP - PPPR - RoutingS - SwitchingT - Token ringX - X.25x - Not applicableThe second character represents protocol.A - AppletalkB - Banyan VinesD - DecnetI - IPL - Dial on DemandN - NLSPO - OSPFX - IPXx - Not ApplicableThe third character represents the certification that the question will help you prepare for.N - CCNA Exam #640-407P - CCNPAdvanced Cisco Router Configuration (ACRC) Exam 640-403Cisco LAN Switch Configuration (CLSC) Exam #640-404Cisco Monitoring and Troubleshooting Dial-up Services Exam #640-405Cisco Internetworking Troubleshooting ( CIT) Exam #640-406D - CCDA & CCDPCisco Design Specialist Exam #9E0-004Cisco Internetwork Design#640-025We will reserve the fourth character for future use.As an example, when you come across a question 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) 96b) 47c) a random number above 1024d) 69e) none of the aboveAnswerd) 69Here 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 commandTrivial File Transfer (TFTP) (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 (21)Simple Network Management Protocol (161)2. [CxNx] What is the standard encapsulation method used by Cisco routers for the Internet Protocol (IP) on it’s Ethernet interfaces?a) SNAPb) ARPAc) NOVELL-ETHERd) DARPAe) Ethernet_802.3Answerb) ARPASNAP is the default encapsulation for a token 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 1.1.1.1 255.255.255.0b) ip address 1.1.1.1c) ip 1.1.1.1d) ip 1.1.1.1 255.255.255.0e) none of the aboveAnswera) ip address 1.1.1.1 255.255.255.0If 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 interface? [yes]:IP address for this interface [10.10.10.1]: 10.10.10.1Number of bits in subnet field [16]: 16Class A network is 10.0.0.0, 16 subnet bits; mask is /24Take note when using the setup mode the mask is configured using the number of subnet bits.4. [CxNx] Which commands will display the IP addresses of all interfaces on a Cisco Router? (Choose all that apply)a) show ip routeb) show ip addressc) show ip interfaced) show interfacee) display ip addressesAnswerc) show ip interfaced) show interfaceExamples of each of these commands are shown below: Router_A#sh int e0/0Ethernet0/0 is up, line protocol is upHardware is AmdP2, address is0010.7b15.bd41(bia 0010.7b15.bd41)Internet address is 10.10.10.1/24MTU 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 clearing 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 throttles, 0 input errors, 0 CRC,0 frame, 0 overrun, 0 ignored,0 abort0 input packets with dribblecondition 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, 0 outputbuffers swapped outRouter_A#sh ip int e0/0Ethernet0/0 is up, line protocol is upInternet address is 10.10.10.1/24Broadcast address is 255.255.255.255Address determined bynon-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 enabledSecurity 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 sameinterface is disabledIP multicast fast switching is enabledRouter Discovery is disabledIP output packet accounting is disabledIP access violation accounting isdisabledTCP/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 the ARP cache of your Cisco router?a) show ip arp cacheb) show ip routec) show ip arpd) show arpe) there is no way to display the ARP cacheAnswerc) show ip arpExample:Router_A#sh ip arpProtocol Address Age(min) Hardware Address Type InterfaceInternet 1.1.1.2 - 0010.7b15.bd50 ARPA FastEthernet1/0Internet 10.10.10.1 - 0010.7b15.bd41 ARPA Ethernet0/06. [CxNx] Reverse Address Resolution Protocol (RARP) is the process:a) Where an IP host resolves it’s IP address by broadcasting it’s MAC address to the network a nd a BOOTP server assigns it an IP address.b) Where an IP host resolves it’s MAC address by broadcasting to the local network it’s IP address.c) Where an IP host tries to resolve the MAC address of a destination by sending a network broadcast. The dest ination responds to the broadcast with it’s 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 it’s IP address.e)There is no such process.Answera) Whe re an IP host resolves it’s IP address by broadcasting it’s MAC address to the network and a BOOTP server assigns it an IP address.Choice C describes Address Resolution Protocol (ARP). A host never has to resolve it’s 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? (Choose all that apply)a) Telnetb) FTPc) TFTPd) SNMPe) none of the aboveAnswera) Telnetb) FTPTFTP and SNMP use layer 4 UDP.8. [RxNx] Which of the following are link state Routing Protocols.(Choose all that apply.)a) IPb) OSPFc) RIPd) EIGRPe) IS-ISAnswerb) OSPFe) IS-ISA link state routing protocol advertises, to it’s 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 router.a) clear ip arp-cacheb) clear ip arp-tablec) clear arp-cached) clear arp-tablee) clear arp-ramAnswerc) clear arp-cacheIf 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 definition of administrative distance as it pertains to Cisco’s 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 it’s 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 will 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.Answerd) 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.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 - 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 - OSPFNSSA 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, * -candidate defaultU - per-user static route, o - ODRGateway of last resort is not set172.16.0.0/24 is subnetted, 2 subnetsC 172.16.1.0 is directly connected,Serial1C 172.16.2.0 is directly connected,Serial0I 10.0.0.0/8 [100/8576] via 172.16.1.1,00:00:09, Serial1[100/8576] via 172.16.2.1, 00:00:19,Serial0The 100 in bold is the administrativedistance for IGRP.A partial list of administrative distances is included below:Protocol ADEIGRP 90IGRP 100OSPF 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 count as it’s metric, while IGRP uses a composite metric including bandwidth and load, speed is the primary consideration.11. [ExNx] Collisions occur whena) multiple packets are placed on a serial linkb) multiple stations listen for traffic and transmit at the same timec) when multiple tokens are on a ring simultaneouslyd) beaconing process takes placeAnswerb) multiple stations listen for traffic and transmit at the same timeCollisions 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 traffic 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 interval 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. 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 255.255.255.252?a) 32b) 30c) 60d) 62e) 4Answerd) 62The above mask is using 6 bits to describe subnets. The formula used to determine the number of subnets (not including the all 0’s or all 1’s subnet) is 2n - 2 were n is the number of subnet bits. This is the number to use when configuring a ip address with the setup dialog.13. [RxNx] What commands will list all protocols that are currently being routed? (Choose all that apply.)a) show ip protocolb) show protocolc) show rund) show starte) All of the aboveAnswerb) show protocolc) show runShow ip protocol will show just the ip routing protocols that are currently configured. Show start may or may not show the current routed protocols.Below is the output of show protocolRouter_B#show protocolGlobal values:Internet Protocol routing is enabledAppletalk routing is enabledBRI0 is administratively down, line protocol is downBRI0:1 is administratively down, line protocol is downBRI0:2 is administratively down, line protocol is downSerial0 is administratively down, line protocol is downSerial1 is administratively down, line protocol is downSerial2 is administratively down, line protocol is downSerial3 is administratively down, line protocol is downTokenRing0 is administratively down, line protocol is down14. [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 permit statement.c) Every access-list will implicitly deny all traffic.d) Access-lists are processed top down.e) All of the above.Answere) All of the above.Every access list has an implicit deny all at the end. What would the need be to create a access list with just deny statements. Access-list are processed from the top down therefore the order of each statement could be critical, for instance suppose you created an access list and the first line was a permit any and the next line was a deny. Since it’s top down processing a packet would be permitted to pass on the first line and the second line would never be executed. An extended list will give you a "match count" that will help in determining what the most efficient order should be.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 will 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.d) The command will be executed and permit all traffic in and out.There are two steps to use an access list .1. Create the list2. Place the access list on a interfaceThe analogy I use in class is:Suppose you reside in a gated community. The community is not protected until you hire the guard and then place him at the gate. If you hire the guard and never place him at the gate all traffic will be permitted. When there is no access list on an interface it is implicit permit anyWhen an access list is placed on a interface it is implicit deny any16. [xxNx] What is the result of the command?" access-list 101 permit tcp any 172.16.0.0 0.0.255.255 established"a) telnet sessions will be permitted regardless of the source addressb) telnet sessions will be denied regardless of the source addressc) telnet sessions will be denied if initiated from any address other than 172.16.0.0 networkd) telnet sessions will be permitted to the 172.16.0.0 network onlye) telnet sessions will be denied to the 172.16.0.0 network onlyAnswerc) telnet sessions will be denied if initiated from any address other than 172.16.0.0 networkThe secret to this question is the key word "established." Established means that the packet will be permitted unless it is the first part of the three way handshake. Recall that when we initiate a TCP connection we have no ACK. How can we acknowledge a sequence number from the other side when we have not established a session with him?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 destination.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.Answera) Standard lists will most likely be placed close to the destination.d) Extended lists will most likely be placed close to the source.A standard list will only check the source address. It makes no difference where the packet is going. If you place a standard list close to the source you could very well be denying that traffic to go to other destinations. An extended list can be placed close to the source because we can permit or deny traffic based upon the source and destination address. This insures that only traffic we wish to have denied is denied.18. [RxNx] Which of the following is most correct?a) IP is to TCP. 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.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) The 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.Answerd) The packet will "die" when it reaches the terminator.２０—３９及答案20. [TxNx] If Host A sends a packet to Host B over token ring, and Host B is not active: a) The 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.21. [TxNx] If Host A sends a packet to Host B over token ring: Host A dies after transmitting, and Host B is not active:a) The 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 Active monitor.22. [FxNx] BECN and FECN are:a) Used to provide keepalives in a Frame Relay environmentb) Used to provide error checking in a Frame Relay environmentc) Used to provide congestion information in a Frame Relay environmentd) Used to provide flow control parameters in a Frame Relay environmente) BECN and FECN are not used in a Frame Relay environment.23. [RxNx] Which of the following are benefits of a Link-State routing protocol? (Choose all that apply.)a) Allows the use of a more robust addressing scheme.b) Allows for a larger scalable networkc) Reduces convergence timed) Allows "supernetting"e) All of the above.24. [OxNx] Which of the following are reasons for the OSI model?a) Standardizes interfacesb) Allows modular engineeringc) Facilitates learning and teachingd) All of the above.25. [RxNx] Which of the following is NOT a ROUTING protocol:a) OSPFb) RIPc) IPXd) EIGRP26. [RxNx] Which statement is NOT true about link state protocols:a) Link state advertisements are sent to all routers in an area.b) Each router executes the SPF algorithm.c) Link state routers keep a topological database of the network.d) Link state routers include the originating router s routing table.e) Link state routers know of possible alternate paths to a particular network.27. [RxNx] Which of the following would NOT appear in a routing table?a) Next hop addressb) Interface Port referencesc) MAC addressd) Network addresse) Metrics28. [OxNx] Which statement is true of the Datalink OSI layer ?a) 802.3 is the MAC sub layer.b) No such thingc) MAC sublayer provides the connection to the network layer.d) MAC sublayer uses SAPS to access the network layer.e) SAP sublayer uses the MAC layer to access the LAN medium.29. [RINx] Given the IP address of 193.243.12.43 and a subnet mask of 255.255.255.128, what is the subnet address?a) 194.243.12.32b) 193.243.0.0c) 194.243.12.43d) 193.243.12.128e) None of the above.30. [CxNx] Cisco uses a naming convention to identify frame types. Which four of the following mappings are correct?Cisco_name = Common_namea) cisco_II = Ethernet_IIb) arpa = Ethernet_IIc) sap = Ethernet_802.3d) sap = Ethernet_802.2 LLCe) Novell Ether = Ethernet_802.2 LLCf) cisco_802 = Ethernet_802.2 LLCg) snap = Token Ring Snaph) snap = Ethernet_SNAP31. [RxNx] In order to communicate throughout an internetwork, which of the following are required. Choose Two.a) The use of a routable protocol such as NetBEUI or LATb) A hierarchical naming scheme server such as DNSc) A host file at each communicating deviced) A two part network addressing scheme such as Network/Hoste) The use of a routable protocol such as IP or IPXf) The use of a routable protocol such as TCP or IPX32. [CxNx] What is the default route on an IP network? Choose one.a) This is the route that will be chosen first by IP for delivery of a datagram.。

ccna考试试题库

ccna考试试题库CCNA（Cisco Certified Network Associate）考试是思科认证网络专家的初级认证，主要测试考生在网络基础、路由、交换、无线和安全等方面的知识。

以下是一些模拟CCNA考试的试题和答案：1. 什么是子网掩码，它有什么作用？答案：子网掩码是一种IP地址的附加信息，用于指定IP地址中网络部分和主机部分的界限。

它的作用是允许路由器区分IP地址中的网络地址和主机地址，从而实现不同网络之间的路由。

2. 描述静态路由和动态路由的区别。

答案：- 静态路由：由网络管理员手动配置的路由信息，不随网络结构的变化而自动调整。

- 动态路由：由路由器根据网络拓扑的变化自动生成和更新的路由信息。

3. 什么是VLAN，它有什么好处？答案： VLAN（虚拟局域网）是一种在交换机上划分不同网络的技术，即使物理上连接在同一交换机上，也可以属于不同的VLAN。

VLAN的好处包括提高安全性、减少广播域、提高网络管理的灵活性等。

4. 简述TCP和UDP的区别。

答案：- TCP（传输控制协议）：提供可靠的、面向连接的传输服务，有流量控制和拥塞控制机制。

- UDP（用户数据报协议）：提供不可靠的、无连接的传输服务，适用于对实时性要求高的应用。

5. 什么是DHCP，它的作用是什么？答案： DHCP（动态主机配置协议）是一种网络管理协议，用于自动分配IP地址和其他网络配置信息给网络中的设备。

它的作用是简化网络配置，避免IP地址冲突。

6. 什么是NAT，它在网络中扮演什么角色？答案： NAT（网络地址转换）是一种技术，允许多个设备共享一个公共IP地址与互联网通信。

它在网络中扮演的角色是节省IP地址资源，隐藏内部网络结构。

7. 什么是STP（生成树协议）？答案： STP（生成树协议）是一种网络协议，用于在局域网中防止网络环路的产生。

通过创建一个无环的逻辑拓扑，STP确保网络的稳定性和可靠性。

8. 描述OSPF（开放最短路径优先）协议的工作原理。

思科第九章考试题及答案

思科第九章考试题及答案一、单项选择题（每题2分，共20分）1. 在思科网络技术中，以下哪个协议用于在IP网络中自动发现网络设备？A. SNMPB. CDPC. RADIUSD. TACACS+答案：B2. 动态路由协议RIP使用哪种度量标准来确定最佳路径？A. 跳数B. 带宽C. 延迟D. 负载答案：A3. 以下哪个命令用于在思科路由器上启用密码加密？A. service password-encryptionB. enable secretC. line vty 0 4D. service config答案：A4. 哪种类型的VLAN可以跨越多个交换机？A. 静态VLANB. 动态VLANC. 本地VLAND. 远程VLAN答案：B5. 在思科路由器上，哪个命令用于查看当前的路由表？A. show ip routeB. show ip interface briefC. show running-configD. show ip protocols答案：A6. 以下哪个命令用于在思科交换机上创建一个新的VLAN？A. vlan databaseB. configure terminalC. switchport mode accessD. vlan 10答案：D7. 在思科设备上，哪个命令用于查看设备的IOS版本？A. show versionB. show running-configC. show startup-configD. show ip interface brief答案：A8. 哪种类型的ACL可以基于时间来过滤流量？A. 标准ACLB. 扩展ACLC. 时间ACLD. 命名ACL答案：C9. 在思科设备上，以下哪个命令用于关闭接口上的CDP？A. no cdp enableB. no cdp runC. no cdp timerD. no cdp transmit答案：B10. 以下哪个协议用于在思科设备上进行远程登录？A. SSHB. TelnetC. HTTPD. FTP答案：A二、多项选择题（每题3分，共15分）1. 以下哪些命令用于在思科设备上配置静态路由？（多选）A. ip routeB. route ipC. ip staticD. ip route 0.0.0.0答案：A, D2. 以下哪些协议用于在思科网络中实现VTP？（多选）A. VTPB. CDPC. SNMPD. RADIUS答案：A, B3. 在思科设备上，以下哪些命令用于配置DHCP服务？（多选）A. ip dhcp poolB. ip dhcp excluded-addressC. ip dhcp serverD. ip dhcp relay答案：A, B4. 以下哪些命令用于在思科设备上配置NAT？（多选）A. ip nat inside source staticB. ip nat outside source staticC. access-listD. ip nat pool答案：A, C, D5. 在思科设备上，以下哪些命令用于配置端口安全？（多选）A. switchport port-securityB. switchport port-security maximumC. switchport port-security violationD. switchport port-security mac-address答案：A, B, C三、简答题（每题5分，共20分）1. 描述思科设备上如何配置端口镜像。

思科python考试题库和答案

思科python考试题库和答案****1. 以下哪个是Python中的合法变量名？- A. 2variable- B. variable-name- C. variable_name- D. variable!name**答案：C**2. Python中的哪个关键字用于定义函数？- A. class- B. def- C. function- D. method**答案：B**3. 在Python中，以下哪个是正确的字符串？ - A. "Hello, World!"- B. 'Hello, World!'- C. `Hello, World!`- D. Both A and B**答案：D**4. Python中的列表和元组有什么区别？- A. 列表可以修改，元组不可以- B. 元组可以修改，列表不可以- C. 列表和元组都可以修改- D. 列表和元组没有区别**答案：A**5. 如何在Python中创建一个空字典？- A. {}- B. []- C. ()- D. None**答案：A**6. 在Python中，以下哪个是正确的注释方式？ - A. // This is a comment- B. # This is a comment- C. /* This is a comment */- D. Both A and B**答案：B**7. Python中的`if`语句后面必须跟一个冒号吗？ - A. 是- B. 否**答案：A**8. 在Python中，以下哪个是正确的列表推导式？ - A. [x for x in range(10)]- B. (x for x in range(10))- C. {x for x in range(10)}- D. Both A and C**答案：A**9. Python中如何实现循环遍历列表中的每个元素？ - A. 使用`for`循环- B. 使用`while`循环- C. 使用`foreach`循环- D. Both A and B**答案：A**10. 在Python中，以下哪个是正确的条件语句？ - A. if x > 0 then print("Positive")- B. if x > 0: print("Positive")- C. if x > 0 print("Positive")- D. Both B and C**答案：B**11. Python中如何定义一个类？- A. class MyClass:- B. define MyClass- C. class MyClass = {}- D. Both A and C**答案：A**12. 在Python中，如何将一个整数转换为字符串？ - A. str(123)- B. int("123")- C. float("123")- D. Both A and B**答案：A**13. 在Python中，以下哪个是正确的导入模块的方式？ - A. import os- B. include os- C. load os- D. Both A and B**答案：A**14. Python中的`None`代表什么？- A. 空值- B. 零- C. 布尔值False- D. 字符串"None"**答案：A**15. 在Python中，以下哪个是正确的异常处理语句？ - A. try: pass except: pass- B. try: pass except Exception: pass- C. try: pass catch: pass- D. Both A and B**答案：B**16. Python中如何定义一个空集合？- A. set()- B. {}- C. []- D. None**答案：A**17. 在Python中，以下哪个是正确的文件打开模式？ - A. 'r'- B. 'w'- C. 'a'- D. All of the above**答案：D**18. Python中如何实现函数的参数默认值？- A. def func(a, b=10): pass- B. def func(a=10, b): pass- C. def func(a, b): b = 10- D. Both A and C**答案：A**19. 在Python中，以下哪个是正确的列表切片操作？ - A. my_list[1:5]- B. my_list[1..5]- C. my_list[1, 5]- D. Both A and C**答案：A**20. Python中如何实现元组解包？- A. a, b = (1, 2)- B. a = b = (1, 2)- C. a = (1, 2)[0]- D. Both A and C**答案：A**21. 在Python中，以下哪个是正确的字典推导式？ - A. {x: x**2 for x in range(5)}- B. [x: x**2 for x in range(5)]- C. {x: x**2 for x in range(5)} = {}- D. Both A and B**答案：A**22. Python中如何实现列表的排序？- A. my_list.sort()- B. sorted(my_list)- C. Both A and B- D. None of the above**答案：C**23. 在Python中，以下哪个是正确的生成器表达式？ - A. (x for x in range(10))- B. [x for x in range(10)]- C. {x for x in range(10)}- D. Both A and B**答案：A**24. Python中如何实现三元条件表达式？- A. x if condition else y- B. if condition: x else y- C. x = y if condition else z- D. Both A and C**答案：A**25. 在Python中，以下哪个是正确的装饰器使用方式？ - A. @decorator- B. decorator()- C. @decorator()- D. Both A and C**答案：D**这些题目涵盖了Python的基础知识点，包括变量命名、数据类型、控制流、函数、类、模块导入、异常处理等，适合作为思科Python考试的题库和答案。

思科期末考试及答案

思科期末考试及答案一、单选题（每题2分，共20分）1. 思科公司（Cisco）成立于哪一年？A. 1984年B. 1985年C. 1986年D. 1987年答案：A2. 以下哪个不是思科公司的主要业务领域？A. 网络设备制造B. 网络安全C. 云计算服务D. 个人电脑制造答案：D3. 思科的网络操作系统（IOS）是基于哪种操作系统开发的？A. UNIXB. LinuxC. WindowsD. Solaris答案：A4. 思科的CCNA认证主要涉及哪个领域的知识？A. 网络安全B. 无线网络C. 网络基础D. 数据中心技术答案：C5. 思科的CCNP认证主要涉及哪个领域的知识？A. 网络安全B. 无线网络C. 网络基础D. 企业级网络架构答案：D6. 思科的CCIE认证是思科认证体系中的哪个级别？A. 入门级B. 中级C. 高级D. 专家级答案：D7. 思科的SD-WAN技术主要解决什么问题？A. 网络安全B. 无线网络覆盖C. 广域网优化D. 数据中心管理答案：C8. 思科的Meraki产品线主要提供什么类型的解决方案？A. 网络安全B. 无线网络C. 广域网优化D. 云管理网络设备答案：D9. 思科的ASA防火墙系列主要提供什么功能？A. 入侵检测B. 防火墙C. 负载均衡D. 无线接入控制答案：B10. 思科的Prime Infrastructure管理平台主要提供什么功能？A. 网络安全管理B. 无线网络管理C. 网络设备配置D. 网络性能监控答案：D二、多选题（每题3分，共15分）11. 思科的网络设备包括哪些类型？A. 路由器B. 交换机C. 无线接入点D. 防火墙答案：ABCD12. 思科的CCNA认证课程通常包括哪些内容？A. 网络基础B. 网络设备配置C. 网络故障排除D. 网络安全答案：ABC13. 思科的CCNP认证课程通常包括哪些内容？A. 路由技术B. 交换技术C. 网络安全D. 网络自动化答案：ABCD14. 思科的SD-WAN解决方案可以提供哪些优势？A. 降低广域网成本B. 提高网络性能C. 简化网络管理D. 提高网络安全性答案：ABCD15. 思科的Meraki产品线可以提供哪些类型的设备？A. 无线接入点B. 交换机C. 安全设备D. 云管理平台答案：ABCD三、判断题（每题2分，共20分）16. 思科公司是由斯坦福大学的两位教授创立的。

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思科认证考试题库 CCNA640-802 V13题库试题分析题库讲解:吴老师(艾迪飞CCIE实验室首发网站: 1、 What are two reasons that a network administrator would use access lists? (Choose two、) A、 to control vty access into a router B、 to control broadcast traffic through a router C、 to filter traffic as it passes through a router D、 to filter traffic that originates from the router E、 to replace passwords as a line of defense against security incursions Answer: AC 解释一下:在VTY线路下应用ACL,可以控制从VTY线路进来的telnet的流量。也可以过滤穿越一台路由器的流量。 2、 A default Frame Relay WAN is classified as what type of physical network? A、 point-to-point B、 broadcast multi-access C、 nonbroadcast multi-access D、 nonbroadcast multipoint E、 broadcast point-to-multipoint Answer: C 解释一下:在默认的情况下,帧中继为非广播多路访问链路。但就是也可以通过子接口来修改她的网络的类型。

3．Refer to the exhibit、 How many broadcast domains exist in the exhibited topology? 思科认证考试题库 A、 one B、 two C、 three D、 four E、 five F、 six Answer: C 解释一下:广播域的问题,在默认的情况下,每个交换机就是不能隔离广播域的,所以在同一个区域的所有交换机都在同一个广播域中,但就是为了减少广播的危害,将广播限制在一个更小的范围,有了VLAN的概念,VLAN表示的就是一个虚拟的局域网,而她的作用就就是隔离广播。所以被VLAN隔离了的每个区域都表示一个单独的广播域,这样一个VLAN中的广播的流量就是不能传到其她的区域的,所以在上题中就有3个广播域了。

4、 A single 802、11g access point has been configured and installed in the center of a square office、 A few wireless users are experiencing slow performance and drops while most users are operating at peak efficiency、 What are three likely causes of this problem? (Choose three、) A、 mismatched TKIP encryption B、 null SSID C、 cordless phones D、 mismatched SSID E、 metal F、 antenna type or direction

Answer: CEF 6、 The command frame-relay map ip 10、121、16、8 102 broadcast was entered on the router、 Which of the following statements is true concerning this command?

A、 This command should be executed from the global configuration mode、思科认证考试题库 B、 The IP address 10、121、16、8 is the local router port used to forward data、 C、 102 is the remote DLCI that will receive the information、 D、 This command is required for all Frame Relay configurations、 E、 The broadcast option allows packets, such as RIP updates, to be forwarded across the PVC、 Answer: E 解释一下:关于命令 frame-relay map ip 10、121、16、8 102 broadcast ,这个命令用于手工静态添加一条映射,到达10、121、16、8的流量封装一个DLCI号为102,而且这条PVC就是支持广播的流量的,比如RIP的更新包。因为在默认的情况下,帧中继的网络为非广播的,而RIP在其上就是无法发包的。

8.Which of the following are associated with the application layer of the OSI model? (Choose two、)

A、 ping B、 Telnet C、 FTP D、 TCP E、 IP Answer: BC 解释一下:在OSI 7层模型中位于应用层的应用有telnet 与 ftp 这两种应用。 9、 For security reasons, the network administrator needs to prevent pings into the corporate networks from hosts outside the internetwork、 Which protocol should be blocked with access control lists?

A、 IP B、 ICMP C、 TCP D、 UDP Answer: B 解释一下:PING命令利用ICMP协议的echo,与 echo-replay两个报文来检测链路就是否连通的。所以如果要阻止PING的流量到网络,就只要过滤掉ICMP的应用就可以了。

10.Refer to the exhibit、 The network administrator has created a new VLAN on Switch1 and added host C and host D、 The administrator has properly configured switch interfaces FastEthernet0/13 through FastEthernet0/24 to be members of the new VLAN、 However, after the network administrator completed the configuration, host A could communicate with host B, but host A could not communicate with host C or host D、 Which commands are required to resolve this problem? 思科认证考试题库 A、 Router(config)# interface fastethernet 0/1、3 Router(config-if)# encapsulation dot1q 3 Router(config-if)# ip address 192、168、3、1 255、255、255、0 B、 Router(config)# router rip Router(config-router)# network 192、168、1、0 Router(config-router)# network 192、168、2、0 Router(config-router)# network 192、168、3、0 C、 Switch1# vlan database Switch1(vlan)# vtp v2-mode Switch1(vlan)# vtp domain cisco Switch1(vlan)# vtp server D、 Switch1(config)# interface fastethernet 0/1 Switch1(config-if)# switchport mode trunk Switch1(config-if)# switchport trunk encapsulation isl Answer: A 解释一下:这就是一个多VLAN间通讯的问题,虽然都同在一台交换机上,但就是由于处在不同的VLAN中,而导致了不同VLAN中的主机就是不能通讯的。这时我们就需要借助与trunk与三层的路由功能了,在交换机与路由器之间封装TRUNK,这样可以允许交换机间的二层的通讯,但就是由于两个VLAN就是划分到不同的网段中的,因此需要借助路由器的路由功能来实现三层的可达,可以将VLAN中的主机的网关指定为路由器与该VLAN相连的子接口的地址,这样VLAN中的数据包就都会发往网关,而由网关来进行进一步的转发。

在这个题中,题目给出了路由器的的子接口的网段,而又给出了VLAN 2与路由器相连的接口