CCNA第四学期章节1-B

哪种说法是对数据链路连接标识符 (DLCI) 的最佳描述？用于标识通过帧中继网络连接的目的路由器的本地地址用于标识虚电路的具有本地意义的地址用于标识路由器和帧中继交换机之间的接口的逻辑地址用于标识 DCE 的逻辑地址2请参见图示。

从该输出可以得到什么结论？Serial 0/0/0 配置了 DLCI 201。

Serial 0/0/0 已启用帧中继逆向 arp 功能。

Serial 0/0/0 配置的 IP 地址为 172.16.4.3。

Serial 0/0/0 已使用frame-relay map ip 172.16.4.3 201 broadcast命令进行配置。

3如果在帧中继多路访问网络上使用 RIP，必须考虑哪些事项？要转发路由更新，必须将frame-relay map命令与关键字broadcast配合使用，以实现地的映射。

必须启用逆向 ARP，以将路由更新广播转化为单播流量，传播至其它帧中继节点。

由于不支持广播流量，无法在帧中继网络上实施 RIPv1。

要转发路由更新，必须启用动态映射。

4请参见图示。

下列关于图中所示输出的说法中哪两项正确？（选择两项。

）本地帧中继接口的 IP 地址是 172.16.1.4。

本地 DLCI 号是 401。

此连接上正在使用逆向 ARP。

此接口处于活动状态，且正在协商配置参数。

此连接上未启用组播。

5当帧中继交换机检测到队列中含有过多待处理帧时，会进行哪三项操作？（选择三项。

）暂停接受超过 CIR 的帧从队列中丢弃设置了 DE 位的帧减少它发往链路的帧的数量与相连的设备重新协商流量控制对来自拥塞链路的所有帧设置 FECN 位对发往拥塞链路的所有帧设置 BECN 位6下列有关帧中继子接口的说法哪一项正确？多点接口会自动转发路由广播，但与点对点子网络相比，这种模式所消耗的 IP 地址较多点对点子接口的作用类似租用线路，且消除了水平分割路由的问题。

带多个 PVC 的接口，每个接口都需要单独的子接口。

CCNA 1 - Chapter 1Posted by beotron at 3:00 PM1. Which of the following descriptions are true regarding the management connections on a Cisco router? (Choose three.)• They are non-network connections.• They are used to connect the router to the rest of the production network.• They are synchronous serial ports.• They are used for initial router configuration.• They are asynchronous serial ports.• They are accessed using their assigned IP address.2. The console port can be used for which of the following? (Choose three.)• debugging.• password recovery.• routing data between networks.• troubleshooting.• connecting one router to another.3. Which of the following describes the function of a WAN?• connects peripherals in a single location.• connects multiple networks in a single building.• provides connectivity on a LAN.• provides connectivity over a large geographic area.4. An internetwork must include which of the following? (Choose three.)• switching.• static addressing.• IETF standardization.• dynamic or static routing.• consistent end-to-end addressing.5. ABC Company just purchased three new routers to start their company network. Which items are needed to establish a terminal session between a PC and the router for the initial configuration? (Choose three.)• straight-through cable.• terminal emulation software.• rollover cable.• RJ-45 to DB-9 connector.• V.35 cable.6.Terminal emulation software, such as HyperTerminal, can be used to configure a router. Which of the following HyperTerminal options shown in the graphic are correctly set to allow configuration of a Ciscorouter? (Choose three.)• bits per second.• data bits.• parity.• stop bits.• flow control.7. Which of the following devices are used in the construction of a WAN? (Choose three.)• hubs.• routers.• communication servers.• transceivers.• modems.• multi-port repeaters.8. Which of the following are functions of RAM? (Choose three.)• contains startup configuration file.• stores routing table.• holds fast switching cache.• retains contents when power is removed.• stores running configuration file.9. Why is a console connection to a router or switch preferred when troubleshooting? (Choose two.) • can be accessed remotely.• does not depend on network services.• displays startup and error messages by default.• does not require special components.10. Which basic components do a router and a standard desktop PC have in common? (Choose three.) • CPU.• hard drive.• input/output interfaces.• keyboard.• monitor.• system bus.11. During the initial configuration of a 2600 series Cisco router, which cable is required for connecting a PC to the console port?• twisted.• crossover.• rollover.• straight.12. A router is composed of many internal components. Which of the following components stores a copy of the router’s configuration file?• metal-oxide memory.• read only memory.• flash memory.• non-volatile random access memory.13. What contains the instructions that a router uses to control the flow of traffic through its interfaces? • packet configuration.• configuration files.• flash memory.• internal components.14. Several Ethernet hosts on a LAN need the gateway services of a Cisco 2500 series router. Which of the following would be needed to physically connect a router to all of the hosts on the LAN? (Choose two.) • a crossover cable between the transceiver on a router and a switch.• a crossover cables between a switch and hosts on a LAN.• a straight-through cable between the auxiliary port on a router and a switch.• a rollover cable between the console port on a router and a switch.• straight-through cables between a switch and hosts on a LAN.• a straight-through cable between the transceiver on a router and a switch.15. Which router component holds the configuration file when power is lost?• volatile random access memory.• read only memory.• non-volatile random access memory.• flash memory.16. Which of the following layers of the OSI model are incorporated in WAN standards? (Choose two.) physical layer.• application layer.• transport layer.• data link layer.• session layer.17. Which of the following are true regarding router interfaces? (Choose three.)• provide temporary memory for the router configuration files.• connect the router to the network for packet entry and exit.• can be on the motherboard or a separate module.• hold the IOS image.• connect the router to LANs and WANs.18. Which of the following tasks can be accomplished through a management connection on a router? (Choose three.)• troubleshooting problems.• monitoring the system.• capturing LAN data packets.• configuring the router.• routing data packets.19. What do routers use to select the best path for outgoing data packets?• ARP tables.• bridging tables.• routing tables.• switching tables.20. Which of the following are functions of NVRAM? (Choose two.)• stores the routing table.• retains contents when power is removed.• stores the startup configuration file.• contains the running configuration file.• stores the ARP table.21. Select the statements that correctly describe flash memory in a 2600 series router? (Choose two.) • holds the startup config uration by default.• can be upgraded with single in-line memory modules.• stores Cisco IOS software images.• stores routing table information by default.• maintains the only copy of an IOS image after the router is booted。

有关下列扩展 ACL 的说法中哪两项正确？（选择两项。

）access-list 101 deny tcp 0.0.0.255 any eq 20access-list 101 deny tcp any eq 21access-list 101 permit ip any any拒绝从网络始发的所有 FTP 流量。

会隐含拒绝所有流量。

会拒绝发往网络的所有 FTP 流量。

会拒绝从网络始发的所有 Telnet 流量。

会允许从网络始发的 Web 流量。

ACL 可使用哪三种参数来过滤流量？（选择三项。

）数据包大小协议簇源地址目的地址源路由器接口目的路由器接口网络管理员需要允许从公司内部发起的会话流量通过防火墙路由器，同时拦截从公司外部发起量。

最适合使用哪种 ACL？动态基于端口的自反基于时间的下列关于 ACL 处理数据包的说法中哪三项正确？（选择三项。

）隐含的deny any会拒绝不符合任何 ACL 语句的所有数据包。

数据包可能被拒绝，也可能被转发，这取决于与该数据包相匹配的语句。

被一条语句拒绝的数据包可能被后续的语句允许。

默认情况下会转发不符合任何 ACL 语句的数据包。

会检查每条语句，直到检测到匹配的语句或到达 ACL 语句列表末尾为止。

会将每个数据包与 ACL 中每条语句的条件相比较，然后才决定是否转发。

请参见图示。

按图中所示的配置，会产生怎样的效果？用户尝试访问网络的主机时会被要求 telnet 至 R3。

与网络上的资源连接的主机空闲超时为 15 分钟。

任何人尝试 telnet 至 R3 时，绝对超时设置均为 5 分钟。

仅在 Serial 0/0/1 上允许 Telnet 访问 R3。

下列关于命名 ACL 的说法，哪两项是正确的？（选择两项。

）只有命名 ACL 才允许注释。

名称可用于帮助标识 ACL 的功能。

命名 ACL 可提供比编号 ACL 更多的具体过滤选项。

某些复杂 ACL（例如自反 ACL）必须在命名 ACL 中定义。

his item references content from the following areas:CCNA Security: Implementing Network Security• 1.3.1 Reconnaissance AttacksWhat is a ping sweep?A ping sweep is a network scanning technique that indicates the live hosts in a range of IP addresA ping sweep is a software application that enables the capture of all network packets sent acrossA ping sweep is a scanning technique that examines a range of TCP or UDP port numbers on a hA ping sweep is a query and response protocol that identifies information about a domain, includindomain.Observable Description Max Value1 correctness of response2 points for Option 10 points for any other option2Which access attack method involves a software program attempting to discover a system password by using an electronic dictbuffer overflow attackport redirection attackDenial of Service attackbrute-force attackIP spoofing attackpacket sniffer attackObservable Description Max Value1 correctness of response2 points for Option 40 points for any other option2How is a Smurf attack conducted?by sending a large number of packets, overflowing the allocated buffer memory of the target deviceby sending an echo request in an IP packet larger than the maximum packet size of 65,535 bytesby sending a large number of ICMP requests to directed broadcast addresses from a spoofed source address on the sameby sending a large number of TCP SYN packets to a target device from a spoofed source addressObservable Description Max Value1 correctness of response2 points for Option 30 points for any other option2A port scan is classified as what type of attack?access attackDenial of Service attackreconnaissance attackspoofing attackObservable Description Max Value1 correctness of response2 points for Option 30 points for any other option2What are the basic phases of attack that can be used by a virus or worm in sequential order?paralyze, probe, penetrate, persist, and propagateprobe, penetrate, persist, propagate, and paralyzepenetrate, persist, propagate, paralyze, and probepersist, propagate, paralyze, probe, and penetrateObservable Description Max Value1 correctness of response2 points for Option 20 points for any other option2What are the three major components of a worm attack? (Choose three.)enabling vulnerabilityinfecting vulnerabilitypayloadpenetration mechanismprobing mechanismpropagation mechanismObservable Description Max Value1 correctness of response Option 1, Option 3, and Option 6 are correct.1 point for each correct option.0 points if more options are selected than required.3Which type of software typically uses a network adapter card in promiscuous mode to capture all network packets that are sent aport scannerping sweeperpacket snifferInternet information queryObservable Description Max Value1 correctness of response2 points for Option 30 points for any other option2An attacker is using a laptop as a rogue access point to capture all network traffic from a targeted user. Which type of attack is ttrust exploitationbuffer overflowman in the middleport redirectionObservable DescriptionMax Value1 correctness of response2 points for Option 30 points for any other option2Which three options describe the phases of worm mitigation? (Choose three.)The containment phase requires the use of incoming and outgoing ACLs on routers and firewalls.The containment phase tracks down and identifies the infected machines within the contained areas.The inoculation phase disconnects, blocks, or removes infected machines.The inoculation phase patches uninfected systems with the appropriate vendor patch for the vulnerability.The quarantine phase terminates the worm process, removes modified files or system settings, and patches the vulnerabilit used to exploit the system.The treatment phase disinfects actively infected systems.ObservableDescriptionMaxValue1 correctness ofresponseOption 1, Option 4, and Option 6 are correct.1 point for each correct option.0 points if more options are selected thanrequired.3Which phase of worm mitigation requires compartmentalization and segmentation of the networdown or stop the worm and prevent currently infected hosts from targeting and infecting other scontainment phaseinoculation phasequarantine phasetreatment phaseObservable Description Max Value1 correctness of response2 points for Option 1 20 points for any other optionWhat is a characteristic of a Trojan Horse?A Trojan Horse can be carried in a virus or worm.A proxy Trojan Horse opens port 21 on the target system.An FTP Trojan Horse stops anti-virus programs or firewalls from functioning.A Trojan Horse can be hard to detect because it closes when the application that launched it closes.Observable Description Max Value1 correctness of response2 points for Option 10 points for any other option2Which two statements are characteristics of a virus? (Choose two.)A virus typically requires end-user activation.A virus has an enabling vulnerability, a propagation mechanism, and a payload.A virus replicates itself by independently exploiting vulnerabilities in networks.A virus provides the attacker with sensitive data, such as passwords.A virus can be dormant and then activate at a specific time or date.Observable Description Max Value1 correctness of response Option 1 and Option 5 are correct.1 point for each correct option.0 points if more options are selected than required.2Which two are characteristics of DoS attacks? (Choose two.)They always precede access attacks.They attempt to compromise the availability of a network, host, or application.They are difficult to conduct and are initiated only by very skilled attackers.They are commonly launched with a tool called L0phtCrack.Examples include smurf attacks and ping of death attacks.Observable DescriptionMaxValue1correctness ofresponseOption 2 and Option 5 are correct.1 point for each correct option.0 points if more options are selected thanrequired.2Which two statements describe access attacks? (Choose two.)Port redirection attacks use a network adapter card in promiscuous mode to capture all network packets that are sent acro Password attacks can be implemented using brute-force attack methods, Trojan Horses, or packet sniffers.Buffer overflow attacks write data beyond the allocated buffer memory to overwrite valid data or exploit systems to execute code.Port scanning attacks scan a range of TCP or UDP port numbers on a host to detect listening services.Trust exploitation attacks can use a laptop acting as a rogue access point to capture and copy all network traffic in a public wireless hotspot.Observable Description Max Value1 correctness of responseOption 2 and Option 3 are correct.1 point for each correct option.0 points if more options are selected than required.2A disgruntled employee is using Wireshark to discover administrative Telnet usernames and passwords. What type of network at describe?Denial of Serviceport redirectionreconnaissancetrust exploitationObservable Description Max Value1 correctness of response2 points for Option 30 points for any other option2Which two network security solutions can be used to mitigate DoS attacks? (Choose two.)virus scanningdata encryptionanti-spoofing technologiesintrusion protection systemsapplying user authenticationObservable Description Max Value1 correctness of response Option 3 and Option 4 are correct.1 point for each correct option.0 points if more options are selected than required.2Users report to the helpdesk that icons usually seen on the menu bar are randomly appearing on their computer screens. What c reason that computers are displaying these random graphics?An access attack has occurred.A virus has infected the computers.A DoS attack has been launched against the network.The computers are subject to a reconnaissance attack.Observable Description Max Value1 correctness of response2 points for Option 20 points for any other option2A network administrator detects unknown sessions involving port 21 on the network. What could be causing this security breachAn FTP Trojan Horse is executing.A reconnaissance attack is occurring.A denial of service attack is occurring.Cisco Security Agent is testing the network.Observable Description Max Value1 correctness of response2 points for Option 10 points for any other option2Which statement accurately characterizes the evolution of network security?Internal threats can cause even greater damage than external threats.Internet architects planned for network security from the beginning.Early Internet users often engaged in activities that would harm other users.Threats have become less sophisticated while the technical knowledge needed by an attacker has grown.Observable Description Max Value1 correctness of response2 points for Option 10 points for any other option2What is considered a valid method of securing the control plane in the Cisco NFP framework?authorization of actionsDHCP snoopingdynamic ARP inspectionlogin and password policyrouting protocol authenticationrole-based access controlObservable Description Max Value1 correctness of response2 points for Option 50 points for any other option2What are two reasons for securing the data plane in the Cisco NFP framework? (Choose two.)to protect against DoS attacksto provide bandwidth controlto force technicians to use SSH and HTTPS when managing devicesto provide a record of who accessed the device, what occurred, and when it occurredto allow users to control the flow of traffic that is managed by the route processor of their network devicesWhich type of security threat can be described as software that attaches to another program tospecific unwanted function?viruswormproxy Trojan HorseDenial of Service Trojan Horse。