CCNA4 v4.0 Final Practical
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培训讲义1培训讲义2000@1632002 年5 月上海2目录前言 (5)第一章介绍 (8)1.1 什么是 (8)1.2 学习内容及目标 (8)1.3 学习基础 (9)1.4 考试申请 (9)第二章课程介绍 (11)2.1 课程特点 (11)2.2 课程目标 (11)2.3 预备知识 (12)2.4 课程安排 (12)2.5 推荐书目 (13)第三章 (15)3.1 提出背景 (15)3.2 模型的提出意义 (16)3.3 模型 (17)3.3.1 物理层 (18)3.3.2 数据链路层 (19)3.3.3 网络层 (20)3.3.4 传输层 (21)3.3.5 会话层 (23)3.3.7 应用层 (24)3.4 数据封装 (25)3.5 模型 (26)3.6 产品选择 (26)第四章a (27)4.1 路由器 (27)4.1.1 路由器硬件构成 (28)4.2 ( ) (29)4.2.1 界面 (30)4.2.2 常用命令 (30)4.2.3 外部配置方式 (32)4.2.4 常用快捷键 (32)4.2.5 (32)4.2.6 (33)4.2.7 口令恢复 (34)32 (36)第五章1900 (36)5.1 ()技术 (37)5.2 的三个功能 (38)5.3 () (40)5.3.1 的步骤 (41)5.3.2 (42)5.3.3 的转发模式 (43)5.4 的配置 (44)5.5 虚拟局域网 (44)5.5.1 什么是? (44)5.5.2 (帧封装技术) (46)5.5.3 () (47)5.5.4 (49)5.5.5 配置 (50)3— (52)第六章 (52)6.1 概述 (52)6.2 地址划分 (56)6.2.1 基本知识 (56)6.2.2 子网划分 (59)6.2.3 一些配置 (59)第七章 (61)7.2 路由分类 (63)7.3 路由协议分类 (65)7.3.1 (65)7.3.2 最佳路由选择 (66)7.3.3 维护路由表 (66)7.3.4 的形成与克服 (67)7.3.5 配置和 (68)第八章 (70)8.1 为什么要使用 (70)8.2 分类 (70)8.3 配置原则 (71)8.4 正确使用 (71)8.5 配置 (72)8.5.1 使用控制访问 (74)4第九章 (75)9.1 广域网 (75)9.1.1 几种常用术语 (76)9.2 几种典型第二层封装协议 (76)9.3 (79)9.3.1 和 (80)9.4 配置 (81)第十章 (82)10.2 三种协议 (84)10.3 的两种接入方法 (84)10.4 配置 (84)10.5 配置按需拔号路由 (85)10.5.1 配置的步骤 (85)第十一章 a (87)11.1 (87)11.2 术语 (88)11.3 常用查看命令 (94)第十二章实验部分 (95)5前言写一本适合喜欢网络新手的培训讲义一直是我的一个想法我接触网络有7 个年头了从最初的3.1下的网络建设开始直到今天的以设备为主的大型网络中间经历了与大多数人一样的学习过程95 年在大学上计算机网络专业的研究生时由于自己本科学的是卫星通信可以说当时对计算机网络一点感觉都没有当初计算机普及率跟现在是不能相提并论的更别说网络了那时能在导师手下独用一台486已经可以在同学中招摇过市了记得有一次在实验室导师让我将一个文件从另外一台机器拷到他的机器上我折腾了半天也不会用脑子里面的计算机网络知识除了其它一点都没有帮上忙当时我就觉得为什么在书本上学的那么多的理论知识可到实际生活中却一点都用不上也许这也正是许多网络新手最初对网络的感觉――神秘不可捉摸看到许多介绍网络知识的书本感到它们要么是面广泛泛而谈看完之后原来是自己都会的东西要么就是点深讲了一大通理论和复杂的算法后除了空白还是空白98 年参加单位超大型网络建设接触了大量网络设备6尤其是路由器喜欢没有别的原因就是因为简捷好用可靠而且它也是一个将理论转换为实际的理想平台对了我不是任何形式的代理我说的只是自己摸索设备的一些心得2001 年年初与一个朋友聊天得知他已是什么了又告诉我什么是以前也了解一些认证情况但从来没有一个实际的全面的认识于是下定决心去考触摸一下认证的感觉过了之后感觉到对自己的工作确实很有帮助提高和纠正了自己在工作中的经验好吧再去考也过了我从到全部是自己学习的只是从网上了许多学习资料而且也得到了许多人的帮助细化了将许多深奥的理论以浅显的方式表述出来理顺和加深了自己对一些网络概念的理解这里我觉得看英文版书要比看中文版书好当然是我的一个目标但是费用是我的一个最大问题我相信许多网络人的共同目标就是何时拿下与朋友们煮酒论英雄!这是一句美国西点军校的名言它告诉我们要勇敢地面对明天因为最困难的日子都过去了还有什么不能坚持下去希望就在前方我想这就是我们在寒冷的冬天的最好的慰籍在此献给所有同行们7我在一个网络培训中心做过讲师用的是教材是公司的幻灯片形式的讲义它没有展开网络知识只是归纳出重要概念和纲目来从严格意义上讲它不能算是一个好的教材所以我结合自己的实际情况和已有的一些资料写了这本讲义由于网络知识涉及面广内容新其中一定有不少不当之处和表达不清的地方希望大家给我批评指正就当是给一个朋友提个醒2002 年5 月25 日上海8第一章介绍1.1 什么是认证分为三个层次分别为认证网络工程师() 初级认证—认证资深网络工程师中级认证—认证互联网工程师() 高级认证1.2 学习内容及目标从学习内容上可分为四大部分主要内容包括网络协议理论基础协议广域网协议局域网广域网解决方案涉及到的内容均为目前中小型网络解决方案中所必需的知识通过认证的工程师将具备如下技能• 安装配置以及运行500 个网络节点规模的网络系统• 能够胜任的路由器管理能力9• 已获得全球500 大企业的认可和接受• 是各跨国公司和电子商务企业所急需的人才• 移民及出国留学可获得技术加分是升职加薪寻找丰厚工作待遇的有力凭证1.3 学习基础只要具有一定的英语基础和基本的计算机应用知识拥有高中以上的学历就可开始的学习课程的特点是入门的起点不高但随着课程的逐步深入您将学习到更高层次的知识与技能最后成为计算机网络应用的高级人才因此是否具有渴望掌握先进网络知识的愿望积极的学习态度以及希望从事计算机网络行业成为高级网络人才的理想是能否学会课程的前提条件当然如果具有良好的基础会达到事半功倍的效果1.4 考试申请至少提前一天个人到考试中心申请认证考试1.5 目标人群10对产品或网络不太熟悉的客户渠道经销商对产品和服务不太了解的网络技术人员中小型企业网的网络管理员在中大型企业中执行桌面支持工作的网络技术支持人员为小型企业环境提供网络设备安装和第一线支持的网络技术人员希望获取授证的人员希望获取授证的人员11第二章课程介绍2.1 课程特点介绍在多协议互连网络中配置交换机和路由器所需的概念命令和相关实验通过讲解讨论演示练习(和实验设计)能够为中小型企业确定和推荐最佳解决方案该课程提供技术支持人员所需的关于产品安装配置以及故障排除方面的知识2.2 课程目标• 确定集线器以太网交换机或路由器的最佳使用环境• 确定多种互连的设备的网络中的地址协议以及链路连接状态• 根据给定的网络设计指标互连交换器和路由器• 在路由器上正确配置各种路由协议和广域网技术• 配置访问列表对网络设备或网段的访问权限以及常规网络流量实施控制12• 检查交换机路由器及其网络服务和协议的运作情况是否符合给定的网络指标2.3 预备知识参加课程应具有基本的网络概念并且接触过或网络建议学员最好具有网络环境里的工作经验详细的预备知识包括对如下内容的基本了解• 常用的网络术语和拓扑结构• 基本的网络设备例如集线器网桥路由器交换机)• 二进制和十六进制的运算及与十进制数字转换( 最好掌握但并非必须要求)• 网络模型• 访问或• 应用95 运行多个应用程序2.4 课程安排课程时间为5 天或10 个晚上具体如下13课次内容备注第一晚1,2 介绍第一天第二晚3,4(操作命令)课程介绍I n t e r n e t 介绍网络基础知识回顾O S I 原理T C P / I P 原理等第第三晚5(路由器组成)二天第四晚6(交换机的工作原理)网络互连配置I O S 基本命令网络环境管理的基本命令; 交换机基本概念第第五晚7()三天第六晚8 地址划分交换机V L A N T C P / I P 的配置T C P / I P 的配置续第第七晚9 路由协议四天第八晚10R I P I R G P O S P F 路由协议工作原理第九晚12,13,14(第五天第十晚实验(实验配置见图) W A N 的配置I S D N 的配置帧中继的配置等2.5 推荐书目在考试之前推荐几本好一点的学习用书结合会达到事半功倍的效果141 思科网络技术学院教程(上,下册)78 元中文版人民邮电出版社特别适合初学者内容通俗易懂3 考试认证考试(640-507)指南83 元(含光盘)中文版人民邮电出版社的考试用书内容覆盖了考试的全部内容也有许多内容已经超出了的考试要求4 因为考试是全英文的所以最好在考试之前再仔细将研读英文版用书目前较流行的英文版用书有3.0 封面有一个骑士头像5 3.1―― 路由交换模拟强烈推荐能完成学习中遇到的绝大部分命令6 3――考试模拟器强烈推荐虽然里面没有所谓的真题但试题内容全部覆盖了的内容是考前巩固已学知识的利器7 出版的学习用书推荐我是用它过的5 官方培训幻灯片15第三章知识点123 ’s 54)5)6)’s7)8)9)3.1 提出背景在70年代网络得到了迅速的发展和应用在当时的情况下已经变成一个非常巨大的网络但是由于各种原因许多网络的设计采用不同的硬件和软件造成一个必然结果就是不同的16网络之间互相不兼容互相不能通信为了解决这个问题国际标准化组织认识到只有制定一个网络模型才能让所有网络设计人员设计出的网络能够互相通信协同工作基于此于1984年提出参考模型即我们常讲到的七层协议国际标准化组织是一个代表了130个国家的标准化组织的集体总部设在瑞士的日内瓦的目标是制定国际技术标准以促进全球信息交换和无障碍贸易你可能认为该组织应被简称为但并不意味着是一个首字母缩略字实际上在希腊语中意味着平等通过这个词汇表达了组织对标准的贡献3.2 模型的提出意义模型的主要目的就是为不同的网络提供互相兼容互相通信在网络领域我们虽然看不见一个网络中两个节点是如何通信的亦可用一个模型对通信过程进行描述通常用来描述网络通信的模型称为开放系统互连模型通过的学习您知道模型的七层结构以及各层之间如何相互作用每层具有的功能当然学习模型不足以成为一个网络专家但是熟悉模型是你17成为网络专家的必要条件3.3 模型在20世纪80年代早期即开始致力于制定一套普遍适用的规范集合以使得全球范围的计算机平台可进行开放式通信创建了一个有助于开发和理解计算机的通信模型即开放系统互连模型模型将网络结构划分为七层即物理层数据链路层网络层传输层会话层表示层和应用层每一层均有自己的一套功能集并与紧邻的上层和下层交互作用在顶层应用层与用户使用的软件如字处理程序或电子表格程序进行交互在模型的底端是携带信号的网络电缆和连接器总的说来在顶端与底端之间的每一层均能确保数据以一种可读无错排序正确的格式被发送注意组成网络部件的组合方式常被描述成它的体系结构体系结构这个词在网络领域反映了这样一个事实就像一幢建筑物包括了许多不同的但被集成在一起的部件电缆服务器协议客户机应用程序网络接口卡等等模型是对发生在网络中两节点之间过程的理论化描述它并不规定支持每一层的硬件或软件的模型但你学习到的有关网络的每件事均能对应于模型中的一层因此不仅应了解各层的名字而且应了解它们的功能及层之间相互作用的方法18图3- 1 描绘了模型层结构应用层()表示层()会话层()传输层()网络层()数据链路层( )物理层()图3 1 模型层结构3.3.1 物理层物理层是模型的最低层或第一层该层定义网络连接机械电气性能定义了包括物理连网媒介如电缆连线连接器在物理层上传输的是0 或1 比特流工作在这一层的典型网络设备为集线器术语第一层协议和物理层协议均是指描述电信号如何被放大及通过电线传输的标准区别以下两个概念*,; ,.19*..连接在上所有计算机处于一个中在中采用()技术避免的发生具体见2-20页3.3.2 数据链路层数据链路层是模型的第二层控制网络层与物理层之间的通信此层数据叫作帧数据链路层的主要功能是将从网络层接收到的数据分割成特定的可被物理层传输的帧,见图3 - 2 示出了802.3的数据帧图(6B)(6B)(6B) (2B) (46-1500B)(4B)图3-2 802.3 帧结构工作在此层的网络设备有如网桥或交换机由于它们要对帧解码并使用帧将数据发送到正确的接收方所以它们工作在数据链路层的以太网()是应用数据链路层技术的一个实例20在层常会提到即地址地址固化在网卡的中所以以简称常见的写法为00-50-04243 地址分为两大部分前24字节为厂商号加上后24字节的厂商自己分配号目的就是为了保证在全世界不会出现同样地址的网卡3.3.3 网络层网络层即模型的第三层关系到子网的运行控制主要功能是将网络地址翻译成对应的物理地址并决定如何将数据从发送方路由到接收方例如一个计算机有一个地址10.34.99.12 和一个物理地址00-60-97-3973 这种编址方案就好像说某某人的姓名和他的身份证号码相对应一样即使还有其他许多人也叫某某但他们的身份证号码是唯一的我们经常提到的地址也称作就定义在网络层地址32字节长分为网络号部分和主机号两部分常见地址的写法为16.100.1.86 对地址的详细讨论见8在网络层要区别与两个概念所谓的是指路由协议如21而是指或协议网络层通过综合考虑发送优先权网络拥塞程度服务质量以及可选路由的花费来决定从一个网络中节点到另一个网络中节点的最佳路径由于网络层处理路由而路由器因为即连接网络各段并智能指导数据传送属于网络层在网络中路由是基于编址方案使用模式以及可达性来指引数据的发送网络层协议还能补偿数据发送传输以及接收的设备能力的不平衡性为完成这一任务网络层对数据包进行分段和重组分段即是指当数据从一个能处理较大数据单元的网络段传送到仅能处理较小数据单元的网络段时网络层减小数据单元的大小的过程重组过程即是重构被分段的数据单元工作在此层的网络设备有路由器或具有第三层交换功能的交换机此层数据叫作数据包3.3.4 传输层传输层负责确保数据可靠顺序无错地从网络A点到传输到网络B点A B点可能在也可能不在相同的网络段上如果没有传输层数据将不能被接受方验证或解释所以传输层常被认为是模型中最重要的一层传输协议同时进行流量控制或是基于接22收方可接收数据的快慢程度规定适当的发送速率除此之外传输层按照网络能处理的最大尺寸将较长的数据包进行强制分割例如以太网无法接收大于1500字节的数据包发送方网络节点的传输层将数据分割成较小的数据片同时对每一数据片安排一序列号以便数据到达接收方节点的传输层时能以正确的顺序重组该过程即被称为排序在网络中传输层发送一个应答信号以通知发送方数据已被正确接收如果数据有错传输层将请求发送方重新发送数据同样假如数据在一给定时间段未被应答发送方的传输层也将认为发生了数据丢失从而重新发送它们工作在传输层的一种服务是协议族中的(传输控制协议) 另一项传输层服务是协议集的在传输层引入两个重要概念面向连接服务和无连接服务即和是在通信前先建立, 这样保证了数据传输的而是不建立连接就传输所以有更少的但不能保证数据的所以我们传要用而网上听歌因为速度更重要丢几个没关系可以用的在常见的里面是,23是对于协议要经过三次握手才能建立连接再进行数据传输三次握手具体过程见图3-4图3-4 的三次握手过程3.3.5 会话层会话层负责在网络中的两节点之间建立和维持通信术语会话指在两个实体之间建立数据交换的连接常用于表示终端与主机之间的通信会话层的功能包括建立通信链接保持会话过程A B,24通信链接的畅通同步两个节点之间的对话决定通信是否被中断以及通信中断时决定从何处重新发送当通过拨号向你的请求连接到因特网时服务器上的会话层向你与你的客户机上的会话层进行协商连接若你的电话线偶然从墙上插孔脱落时你机上的会话层将检测到连接中断并重新发起连接会话层通过决定节点通信的优先级和通信时间的长短来设置通信期限3.3.6 表示层表示层如同应用程序和网络之间的翻译官在表示层数据将按照网络能理解的方案进行编码这种编码也因所使用网络的类型不同而不同表示层协议还对图片和文件格式信息进行解码和编码3.3.7 应用层模型的第七层是应用层应用层负责对软件提供接口以使程序能使用网络服务术语应用层并不是指运行在网络上的某个特别应用程序如应用层提供的服务包括文件传输文件管理以及电子邮件的信息处理程序可以独立运行而不管发送数据时目标节点是否被连接到网络上在宽带网设计中经常会遇到第七层交换机就工作在这一层它主要起到应用25程序负载均衡作用3.4 数据封装在模型中的每一层都使用它自己的协议和接收设备的对等层通信每一层通过协议数据单元交换数据包括控制信息和数据两部分在模型中将控制信息和数据绑定的过程称作封装当某一层收到上一层之后它便进行封装过程将收到的当作本层的数据部分再加上本层的控制头信息和控制尾信息形成本层的交给下一层处理如图3-5所示N发送进程接收进程010111000101010101010126图3-5 数据封装过程概括来讲数据封装的五步为1 . ( )2 ( )3 (4 ()5 . ( )3.5 模型为了简化网络设计和管理公司提出一个三层模型来描述网络这三层为2 6到2 9快速交换层高档交换机策略层2 8页路由器终端用户接入点或3.6 产品选择具体见从2-40到2-46页公司为了简化产品选择工作27编制一个软件可以到网上第四章a的第三章第四章第五章节主要讲解设备交换机和路由器以及的一些基本知识突出实践经验知识点分布得比较散乱希望大家仔细看书4.1 路由器路由器或分为固定配置和模块化两大类路由器是考试中最重要的概念路由器有多个连接多个不同的路由器通过来决定往哪边传永远不可能往两个上传万一遇到这种情况会把掉可以人工加也可以使用如或动态维护路由器工作在283 44.1.1 路由器硬件构成路由器有六大部分组成分别为1 ――主要运行和2 ――含有用于路由器的启动和维护3 ――含有相当于机的硬盘4)―― 非易失性用于储存配置文件如文件和5 ――控制路由器启动过程具体见5-226)――主要有: 本地配置端口要用( 的原装是蓝色的)一头连在上另一头连在机的口上然后用登录进行配置一般情况下路由器都是用进行配置的这种情况也叫带内配置0代表第一个: 辅助的意思就是用连接进行远程调试路由器用处不是很大在某些路由器里面都没29有这以太口或快速以太口用于连接局域网e0 代表第一个如果是第一个的话用0 来表示分为固定配置和模块化配置两种情况在模块化配置情况下还需要购买卡如( )一般用s0代表第一个用于连接路由器的接口命名规则是按从右往左从下往上的顺序排列的比如有两个左边那个就是e1 右边那个就是e0 如果这两个是上下排列的下面那个就是e0 上面那个就是e1 在有的里面一个里面会有多个这时候你可以用e1/0 e1/1 e1/2 等符号来表示4.2 ( )正如的叫的叫其实里面的都很便宜的大多数也就是486 的水平现在的也就卖几百美金为什么这个小小的就敢卖好几千的美金就应该是这个30如果说是靠垄断了市场那么说是靠来垄断了市场真是一点都不为过4.2.1 界面是( ) 的象里面的都是的而是() 的特点是比较难学但配置起来比较快现在也正在做的,但大家还是喜欢的件进行练习有两种方式和在学习命令的时候一定要记住所使用的命令处于何种提示符下在中经常会遇到以下提示符如下表提示符描述>()# 全局配置模式()# 端口配置模式()# 子端口配置模式()# 配置模式如异步拨入() # 动态路由协议配置如4.2.2 常用命令在中我们要掌握和熟记一些常用命令见下表31命令描述查看版本号显示当前在内存中运行的配置信息显示保存于中的配置信息显示内容如名称大小查看端口状态16.100.1.5 255.255.255.0 在端口上配置地址进入菜单配置模式进入全局配置模式修改路由器或交换机名称() 0()()配置进入口口令() 0 4()()配置进入口令() 进入口令() 代替口令640000 在端口设置通信速率为64K64 在命令中会表现出来它设定路由协议所能使用的带宽而非通信线路上的实际带宽() 使能一个端口0 查看某个端口的电缆类型为或为查看建立会话个数查看口是否在使用并列出所有会话有关之间的转换关系见的5-27页10.5.5.3 设定网关地址帮助命令> -> -> ->32注意在上配置只是为了利于远程管理4.2.3 外部配置方式外部配置方式有12)3)4)5)4.2.4 常用快捷键- a- a- a--( ) -( ) -( ) -( ) ---- .- a4.2.5是特有的用于收集直接相邻设备信息的管理工具工作在模型的33层采用帧结构默认情况下是的每60秒发送一次广播它的是180秒涉及的有一些命令有() ――启动() ――关闭() 30――设置广播时间() 120――设置保留时间――查看直接相邻设备五大类信息如4.2.6用于控制路由器启动过程其工作原理类似机中的在默认情况下它的值为0x2102 可以用命令来查看长为16 其中低4叫作设置不同的值可以让路由器启动到不同的工作状态具体为0x0(0000) 启动到状态提示符为或>0x1(0001) 从启动提示符为()0x2(0010)-0(1111) 正常启动到中查找命令34及其含义含义0x2102 缺省设置13=0x2000 引导失败5次后自动从引导8=0x0100 关闭键0x2 从中引导正常运行模式0x210113=0x2000 引导失败5次后自动从引导8=0x0100 关闭键0x1 进入运行模式()>0x1428=0x0040 进入运行模式>0x2 从中引导正常运行模式4.2.7 口令恢复。
公司与AA2SSH存在不正确的访问控制列表条目。
访问列表中的必须在会防止以明文传输登录信息如果身份验证失败,则会断开PPP 会话连接会发起双向握手容易遭受回送攻击4命令show frame-relay map的输出如下:Serial 0 (up): ip 192.168.151.4 dlci 122, dynamic, broadcast, status defined, active 下列哪三种说法正确描述了所示内容的意义?(选择三项。
)192.168.151.4代表远程路由器的IP 地址192.168.151.4代表本地串行接口的IP 地址DLCI 122代表远程串行接口DLCI 122代表用于连接远程地址的本地编号broadcast表示动态路由协议(例如RIP v1)可通过此PVC 发送数据包active表明ARP 进程正在工作5路由器的SDM 主页会显示哪三点信息?(选择三项。
)ARP 缓存闪存的总容量和可用容量路由表已配置的LAN 接口的数量是否配置了DHCP 服务器该LAN 中路由器的数量6从非军事区分界点本地环路网云确保在确认确保路由器上有通向下列哪三种说法正确描述了CSU/DSU调制解调器用于端接本地数字环路。
CSU/DSU调制解调器用于端接本地模拟环路。
路由器通常被视为路由器通常被视为10在链路质量测试完毕后,路由器在协商第LCPNCP它会被丢弃。
它会被放到队列中,直到主机它会被转换,源端口号保持为它会被分配其端口范围内的第一个可用端口号。
交换虚电路的相关信息将DLCI 映射到网络地址提供流量控制提供错误通知提供拥塞通知发送keepalive 数据包以检验PVC 的工作情况14请参见图示。
下列说法中哪三项正确?(选择三项。
)启用了NAT 过载。
启用了动态NAT。
地址转换会失败。
接口配置不正确。
地址为192.168.1.255 的主机将被转换。
进入0/0/2 接口的流量先被转换,然后才流出串行接口0/0/0。
ccnafinal1.哪些通讯工具允许实时协作?维基电子邮件博客即时通讯*2.主机在访问远程网络上的Web服务器。
这三种功能是通过中介的网络设备在此对话期间进行的?(选择三项。
)再生数据信号*作为客户端或服务器提供超过其消息出行通道应用安全设置来控制数据流*通知其它设备发生错误时*作为报文的源或目的地3.家庭用户正在寻找一个ISP的连接,超过普通电话线提供高速数字传输。
什么ISP连接类型应该使用吗?DSL*拨号卫星细胞调制解调器电缆调制解调器4.公司正在扩大其业务至其他国家。
所有分公司必须始终保持连接到公司总部。
哪个网络技术需要支持这一要求?LANMANWAN*WLAN5.请参见图示。
从该位置会出现这种路由器装载IOS?闪存NVRAMRAMROMTFTP服务器6.哪些连接提供加密的安全CLI会话到思科的网络设备?控制台连接AUX连接Telnet连接SSH连接*7.请参见图示。
管理员试图配置交换机,但接收显示在展览的错误消息。
有什么问题?模式。
*管理员必须通过控制台端口连接到进入全局配置模式。
8.管理员发出ping命令后,使用一个开关上的Ctrl-Shift键-6组合键。
什么是使用这些按键的目的是什么?重启平过程打断平过程*退出到不同的配置模式以允许用户完成该命令9.进入IOS命令何时按下Tab键有什么功能?它中止当前命令并返回到配置模式。
它退出配置模式并返回到用户EXEC模式。
它的光标移动到下一行的开头。
它完成了在命令部分输入的单词的剩余部分。
*10.请参见图示。
管理员要改变一个全新的交换机的名称,使用hostname命令,如图所示。
将显示提示什么发出命令后?My Switch(config)#?Switch(config)#?*MySwitch(config)#?My(config)#?Switch#11.请参见图示。
网络管理员正在配置访问控制开关SW1。
如果管理员使用Telnet连接到交换机,该交换机密码来访问用户EXEC模式需要的?letmeinsecretinlineconinlinevtyin*12.进行配置更改后,网络管理员在Cisco交换机发出一份running-config来startup-config命令。
CCNA4.0 注册指南及四期考试
共有四期考试,第一期考试为网络基础;第二期为路由及路由协议;第三期为交换及无线局域网;第四期为广域网访问技术。
每期考试都有具体的安排应操作的内容,完成考试后需要马上进入反馈表填写;
每次考试采用注册后的用户名和密码登陆,
1.登陆/web/learning/netacad/index.html在图中红圈处输入ID号和密码。
2.按第一步正确进入后点击“同意”“accept”按钮
4.进入用户信息设置窗口
注册完后帐号的使用说明
1./web/learning/netacad/index.html登陆学习网站
2. 输入帐号密码
3.进入学习平台内部
4.在学习平台界面选择CCNA2009-9-1的这期课程:
点击进去
5. 选择CHINESE SIMPLIFIED
6. 再选择CCNA EXPLORA TION,再SUBMIT
7.进入到学习软件里
8. 进入到EXPLORA TION路由知识的学习。
CCNA Exploration: 网络基础知识(版本4.0)第二章1.下列哪些陈述正确指出了中间设备在网络中的作用?(选择三项)答案:1,确定数据传输路径3,重新定时和重新传输数据信号5,管理数据流2.请选择关于网络协议的正确陈述(选择三项)答案:1,定义特定层PDU的结构3,概述层与层之间通信所需的功能5,需要取决于协议层的封装过程3.封装的两个功能是什么?(选择两项)答案:4,标识属于同一通信的数据片段5,确保数据片段可以转发到正确的接收端设备4.数据链路层封装添加的报尾信息有何主要功能?答案:1,支持差错校验5.OSI模型哪两层的功能与TCP/IP模型的网络接入层相同?(选择两项)答案:3,物理层4,数据链路层6.什么是PDU?答案:4,特定层的封装7.以下哪种特征正确代表了网络中的终端设备?答案:2,发送数据流8.请参见图示。
IP地址为10.0.0.34的“手机A”已经与IP地址为172.16.1.103的“IP电话1”建立了IP会话。
请根据图示回答,下列哪个设备类型是对无线设备“手机A”功能的最准确描述?答案:2,终端设备9.请参见图示。
下列哪三个标签正确标识了图示网段的网络类型?(选择三项)答案:2,网络B—WAN 3,网络C—LAN 6,网络A—LAN10.下列哪三项陈述是对局域网(LAN)最准确的描述?(选择三项)答案:1,LAN通常位于一个地域内2,此类网络由一个组织管理5,LAN为同一个组织内的用户提供网络服务和应用程序访问11.请参见图示。
哪个网络术语描述了图中所示的数据交替发送过程?答案:4,多路复用12.第4层端口指定的主要作用是什么?答案:5,标识终端设备内正在通信的进程或服务13.哪种设备被视为中间设备?答案:5,交换机14.请参见图示。
哪个术语正确判断出了包含于区域B中的设备类型?答案:4,中间设备15.请参见图示。
所示网络属于哪一类型?答案:3,LAN16.哪一层负责将数据段封装成数据包?答案:3,网络层17.通过检查网络层头部可以确定什么?答案:2,目的主机地址18.请参见图示。
CCNA专业英文词汇全集(1—4)CCNA专业英文词汇全集(1)CCNA为思科最基础的入门认证,其中,考试偏重网络概念和理论,对于初学者来说,不少专业英文术语难以理解,导致学员学习进度维难。
CISCO系列认证的原版教材,专业词汇出现频率积高,考生只要熟悉本文,相信学习起来一定事半功倍。
10BaseT-----原始IEEE802.3标准的一部分,1OBaseT是1OMb/s基带以太网规范,它使用两对双绞电缆(3类、4类或5类),一对用于发送数据另一对用于接收数据。
1OBaseT每段的距离限制约为100米。
参见Ethernet和IEEE 802.3。
1OOBaseT-----基于IEEE 802.3U标准,1OOBaseT是使用UTP接线的基带快速以太网规范。
当没有通信量出现时。
1OOBaseT在网络上发送链接脉冲(比1OBaseT中使用的包含更多信息)。
参见10BaseT、Fast Ethernet和IEEE 802.3。
100BaseTX-----基于IEEE 802.3U标准,100BaseTX是使用两对UTP或STP接线的10OMb/S 基带快速以太网规范。
第一对线接收数据;第二对线发送数据。
为确保正确的信号定时,一个100BaseTX网段不能超过100米长。
A&B bit signaling (A和B比特信令)-----用于T-1传输设备,有时称为"第24信道信令"。
在这一方案中,每个T-1于信道使用每个第六帧的一个比特来发送监控信令信息。
AAA-----身份验证(Authentication)、授权(Authorization)和统计(Accounting)Cisco开发的一个提供网络安全的系统。
奏见authentication。
authorization和accountingAAL ATM适应层-----数据链路层的一个与服务有关的子层,数据链路层从其他应用程序接受数据并将其带人ATM层的48字节有效负载段中。
1下列哪种类型的网络攻击是利用被入侵的系统中的漏洞在网络中自我传播?病毒蠕虫特洛伊木马中间人2请参见图示。
有一个FTP 请求数据包需要发往IP 地址为172.16.1.5 的FTP 服务器。
Router1 的S0/0/0 接口收到该请求数据包后,会以何种方式处理?路由器认定传入数据包与access-list 201 permit ip any any命令创建的语句匹配,从而允许数据包进入路由器。
因为access-list 101 permit ip any any命令没有创建任何语句,所以路由器会达到ACL 101 的尾部而找不到匹配的条件,从而丢弃该数据包。
路由器认定传入数据包与access-list 101 permit ip any 172.16.1.0 0.0.0.255命令创建的语句匹配,从而忽略ACL 101 的其余的语句,允许数据包进入路由器。
路由器会认定传入数据包与命令access-list 201 deny icmp 172.16.1.0 0.0.0.255 any创建的语句匹配,然后继续将该数据包与ACL 201 中剩余的语句比对,以确保后续语句均未禁止FTP,然后路由器将丢弃该数据包。
3管理员正在使用RIPng 和双协议栈技术为一路由器配置IPv6 和IPv4,他在输入IPv4 路由时收到一条错误消息。
可能是什么原因导致出现错误消息?IPv4 与RIPng 不兼容RIPng 与双协议栈技术不兼容。
路由器接口的地址配置错误。
在同一接口同时配置IPv4 和IPv6 时,所有IPv4 地址均被禁用,以支持新的技术。
4帧中继网络中所用的本地管理接口(LMI) 提供哪两项功能?(选择两项。
)流量控制错误通知拥塞通知映射DLCI 至网络地址发送keepalive 数据包以检验PVC 的工作情况5如果不以纯文本格式发送身份验证信息,在Cisco 和非Cisco 路由器之间建立链路连接时,应使用以下哪种第2 层协议和身份验证的组合?HDLC 与PAPHDLC 与CHAPPPP 与PAPPPP 与CHAP6服务提供商自何处开始对客户的WAN 连接负责?本地环路路由器上的DTE 电缆分界点非军事区7请参见图示。
CCNA详解:CCNA认证(CCNA-思科网络安装和支持认证助理)是整个Cisco认证体系中最初级的认证,同时它也是获得CCNP认证、CCDP认证和CCSP认证的必要条件(CCIP认证、CCIE认证不强制要求),而且许多Cisco 专业认证(Cisco Qualified Specialist)也要求考生首先得具备的CCNA认证。
CCNA认证属于Cisco售后工程师认证体系的入门认证,通过CCNA可以证明你已掌握网络的基本知识,并能初步安装、配置和操作Cisco路由器、交换机及简单的LAN和WAN。
CCNA认证表示经过认证的人员具有为小型办公室/家庭办公室(SOHO)市场联网的基本技术和相关知识。
通过CCNA认证的专业人员可以在小型网络 (100或100以下个节点)中安装、配置和运行LAN、WAN和拔号访问业务。
他们可以使用的协议包括(但不限于):IP, IGRP, IPX, Serial, AppleTalk, Frame Relay, IP RIP, VLAN, RIP, Ethernet, Access Lists.获得CCNA认证的先决条件不需要考生持有任何证书即可报考CCNA,同时对考生的年龄、学历、外语水平均没有硬性规定;CCNA认证的考试现在参加考试有2条途径:一、参加640-801 CCNA这一门考试;二、参加640-821 INTRO和640-811 ICND 这两门考试;CCNA认证的有效期CCNA证书的有效期为3年,3年之后需要参加再认证(Recertification)的考试,如果你在这2年时间内考取了更高级别的Cisco认证,则CCNA认证的有效期自动更新。
CCNA的再认证考试有效期满之后必须参加640-811 ICND的考试,或者参加任何一科CCNP、CCDP、CCIP、CCSP的考试,再或者参加Cisco专业认证(Cisco Qualified Specialist)中任何一科前缀为642-XXX的考试。
CCNA复习知识点第一章:网际互联1、什么是互联网络当用路由器将两个或多个LAN或WAN连接起来,并用协议(如IP)配置逻辑网络寻址方案时,就创建了一个互联网络。
2、网络分段随着网络规模的不断增长,LAN中的流量拥塞会变得让人无法忍受。
解决这个问题的方法是,将一个很大的网络划分为一些小的网络,称为网络分段。
可使用路由器、交换机、和网桥来实现网络分段。
3、广播域所谓广播域是指网段上所有设备的集合,这些设备收听到送往那个网段的所有广播。
4、在网络中使用路由器的好处A:默认时路由器不会转发广播B:路由器可以根据第3层(网络层)信息(比如IP地址)对网络进行过滤5、路由器的四种功能数据包转发数据包过滤网络之间的通信路径选择)模型Application Layer:是实际应用程序之间的接口。
还负责识别并建立想要通信的计算机一方的可用性,并决定想要的通信是否存在足够的资源。
Presentation Layer:为应用层提供数据,并负责数据转换和代码的格式化。
如数据压缩、加密解密、多媒体操作等。
Session Layer :负责建立、管理和终止表示层实体之间的会话连接。
提供3种不同的方式来组织它们之间的通信,单工、半双工和全双工。
使不同应用程序的数据与其他应用程序的数据保持隔离。
-----------------------------上三层定义了终端系统中的应用程序将如何彼此通信------------------------------------------------下四层定义了怎样进行端到端的数据传输-----------------------------------Transport Layer :将数据分段并重组为数据流。
在互联网络的发送方主机和目的主机之间建立逻辑连接。
提供的功能有:流量控制、可靠的(面向连接的、窗口机制、确认)或不可靠的通信。
Network Layer :负责设备寻址,跟踪网络中设备的位置,并决定传送数据的最佳路径,这意味着网络层必须在位于不同地区的互联设备之间传送数据流。
思科认证网络工程师(CCNA)课程大纲CCNA课程目标完成整个CCNA课程学习后,网络工程人员能够:1 描述网络如何工作●描述不同网络设备的功能和作用●选择网络组件●使用OSI参考模型以及TCP/IP模型的相关协议解释数据如何在网络进行传输●描述基本的网络应用,包括WEB●描述OSI参考模型以及TCP/IP模型中相关协议的功能及其基本原理。
●描述V oice Over IP以及Video Over IP对网络的影响。
●理解网络拓扑图●确定主机间数据传输的路径●描述网络以及Internet通讯的组件●确定并处理网络中1层、2层、3层以及7层故障●区别LAN与WAN●2交换机的配置、验证以及故障排查●选择正确的介质、线缆、接口和连接器来完成交换机与其他网络设备以及主机的连接●解释Ethernet网中Media Access Control技术●解释网段以及基本的流量管理概念●解释基本的交换概念以及Cisco交换机的工作原理●完成交换机的初始化配置,包括对交换的远程管理●使用基本的工具(ping、traceroute、telnet、SSH、ARP、ipconfig)、SHOW以及DEBUG验证网络以及交换机●分析、确定并解决交换网络中介质问题、配置问题、自动协商以及交换机硬件故障●描述增强的交换网络技术(VTP、RSTP、VLAN、PVSTP、802.1q)●描述VLAN如何创建逻辑上隔离的网络,VLAN间通讯需要进行路由●VLAN配置、验证以及故障排查●Cisco 交换机Trunk配置、验证以及故障排查●VLAN间路由配置、验证以及故障排查●VTP配置、验证以及故障排查●RSTP配置、验证以及故障排查●理解SHOW以及DEBUG命令显示的信息,并根据信息验证Cisco交换网络的工作状态●实施基本交换机安全(port security、trunk access等)3实施IP编址以及IP服务●描述私有地址以及公有地址使用优点以及工作原理●解释DCHP以及DNS的优点以及工作原理●路由器上DHCP以及DNS配置、检查以及故障排查●在LAN中,为主机实施静态以及动态地址分配●实施IP编址,包括VLSM地址分配●在LAN/WAN中实施VLSM以及地址汇总●描述IPv6与IPv4的共存技术(包括协议、双栈以及隧道等)●描述IPv6编制●分析并解决基本IP地址分配问题4 路由及路由器配置、验证以及故障排查●描述路由概念●描述路由器工作原理●选择正确的介质、线缆、接口以及连接器完成路由器与其他网络设备和主机的连接●RIPv2配置、验证以及故障排查●访问路由器并进行基本配置(CLI/SDM)●路由器接口配置、验证以及故障排查●验证路由器配置、使用ping, traceroute, telnet, SSH或其他工作验证网络的连通性●实施并验证静态路由以及默认路由配置●管理IOS配置文件●管理Cisco IOS●比较不同的路由技术以及路由协议●OSPF配置、验证以及故障排查●EIGRP配置、验证以及故障排查●排查路由问题●使用SHOW以及DEBUG命令验证路由器硬件和软件工作状态●实施基本路由器安全5WLAN管理●描述无线介质相关标准●描述小型WLAN中组件的功能(包括SSID、BSS以及ESS等)●在WLAN配置基本参数,确保设备连接到正确的访问点●比较WALN安全特性以及WPA安全的功能●分析并解决在WLAN实施过程中遇到的基本问题6网络安全●描述当今网络安全所面临的问题并解释实施复杂的网络安全策略以应对网络安全的需要●解释缓解对网络设备、主机以及应用安全问题的通用技术●描述基本网络安全设备以及安全应用的功能●描述推荐的实施安全的做法,包括最初的步骤,以确保网络设备7 NAT以及ACLs配置、验证以及故障排查●描述ACLs类型以及功能●配置ACLs以实施数据过滤●配置ACLs以实施对于Telnet以及SSH的访问限制●验证并监控网络中的ACLs●排查ACLs问题●解释NA T工作原理●配置NAT●排查NA T问题8 实施、验证WAN链路●描述不同的WAN链路技术●HDLC配置、验证●Frame-relay配置、验证●PPP配置、验证●排查WAN实施中的问题●描述VPN技术课程知识点课程知识点简介CCNA 理论课程理解网络基础概念理解以太网技术基础理解网络模型,七层OSI理解TCI/IP理解网络传输介质,例如铜缆、光纤、无线理解IP寻址理解路由的原理和概念学习RIP第二版理解IOSPF、EIGRP基础学习IOS管理理解I路由器配置基础理解I访问控制表学习网络故障排除技能理解IVLSM基础学习交换机配置理解生成树协议理解虚拟局域网学习虚拟中继协议理解I虚拟局域网间路由理解I扩展IP地址、NAT和PAT理解IDHCP协议I理解ISDN和DDR理解I帧中继理解IPPP理解I网络管理协议基础、SNMP实验课程访问Cisco设备的方法1.1 实验1:通过Console端口访问Cisco路由器1.2 实验2:通过Telnet访问Cisco路由器1.3 实验3:配置终端服务器1.4 实验4:通过浏览器访问路由器IOS软件的基本操作2.2 实验1:模式切换、上下文帮助及查看有关信息2.3 实验2:使用历史记录、系统日志及调试工具2.4 实验3:使用安装模式配置路由器2.5 实验4:路由器的口令设置和口令恢复2.6 实验5:管理配置文件2.7 实验6:备份和升级IOS软件局域网交换机配置3.2 实验1:交换机启动及基本设置3.3 实验2:交换机端口和MAC地址表的设置3.4 实验3:VLAN、VLAN Trunk、VTP和STP配置IP、静态路由及CDP协议4.2 实验1:熟悉常用的IP相关命令4.3 实验2:静态路由的设置及相关命令4.4 实验3:使用回送接口、扩展的ping和trace 4.5 实验4:配置CDP协议路由选择协议、RIP和IGRP5.2 实验1:RIP协议的基本配置5.3 实验2:使用RIP协议处理不连续的子网和VLSM 5.4 实验3:IGRP协议的基本配置5.5 实验4:IGRP协议的高级配置EIGRP协议配置6.2 实验1:EIGRP协议的基本配置6.3 实验2:使用EIGRP的监测和诊断命令6.4 实验3:EIGRP高级配置ISDN、PPP和DDR技术7.2 实验1:ISDN基本配置7.3 实验2:PPP认证、DDR和Multilink7.4 实验3:配置ISDN接口作为备份接口配置帧中继8.2 实验1:配置帧中继交换机8.3 实验2:基本的帧中继配置8.4 实验3:配置帧中继子接口IPX协议配置9.2 实验1:基本的IPX配置9.3 实验2:配置和查看IPX路由和SAP服务配置访问控制列表10.2 实验1:IP访问控制列表10.3 实验2:IPX访问控制列表配置OSPF协议11.2 实验1:配置和查看OSPF协议11.3 实验2:监测和调试OSPF协议配置NAT12.2 实验1:配置和监测静态内部源地址转换12.3 实验2:配置和监测动态内部源地址转换12.4 实验3:配置和监测复用内部全局地址NAT配置Cisco 2950交换机实验1:2950交换机的启动及基本设置实验2:配置VTP、VLAN和VLAN Trunk考核答疑针对学习本课程中的任何相关疑问本课程总计学时:48学时。
1. What functionality do access control lists provide in the implementation of dynamic NAT on a Cisco router?define which addresses can be translateddefine which addresses are assigned to a NAT pooldefine which addresses are allowed out the routerdefine which addresses can be accessed from the inside network2. Which three guidelines would help contribute to creating a strong password policy? (Choose three.)Once a good password is created, do not change it.Deliberately misspell words when creating passwords.Create passwords that are at least 8 characters in length.Use combinations of upper case, lower case, and special characters.3.Refer to the exhibit. Every time the administrator reboots this router, the boot process ends in setup mode. What is a possible problem?There is insufficient RAM for the IOS to load on this router.A password recovery process should be done on this router.The bootstrap version and the version of the IOS are different.The IOS image is damaged and must be reloaded using tftpdnld.The configuration register is set to ignore the startup configuration.4. Which option correctly defines the capacity through the local loop guaranteed to a customer by the service provider?BEDECIRCBIR5.Refer to the exhibit. A host connected to Fa0/0 is unable to acquire an IP address from the DHCP server. The output of the debug ip dhcp server command shows "DHCPD: there is no address pool for 10.1.1.1". What is the problem?The 10.1.1.1 address is already configured on Fa0/0.The default router for the 10Network pool is incorrect.The ip helper-address must be added to Fa0/0 interface.The pool of addresses for the 10Network pool is incorrect.6. Which data link layer encapsulation protocol is used by default for serial connections between two Cisco routers?ATMFrame RelayHDLCPPPSDLCRefer to the exhibit. Which statement correctly describes how Router1 processes an FTP request that enters interface s0/0/0 and is destined for an FTP server at IP address 192.168.1.5?The router matches the incoming packet to the statement that was created by the access-list 201 deny icmp 192.168.1.0 0.0.0.255 any command, continues comparing the packet to the remaining statements in ACL 201 to ensure that no subsequent statements allow FTP, and then the router drops the packet.The router reaches the end of ACL 101 without matching a condition and drops the packet because there is no statement that was created by the access-list 101 permit ip any any command.The router matches the incoming packet to the statement that was created by the access-list 101 permit ip any 192.168.1.0 0.0.0.255 command and allows the packet into the router.It matches the incoming packet to the statement that was created by the access-list 201 permit ip any any command and allows the packet into the router.8. Compared with IDS systems, what can IPS systems do to provide further protection of computer systems?detect potential attacksstop the detected attack from executingupdate OS patches for computer systemsscan computer systems for viruses and spyware9. Which IEEE 802.16 broadband wireless technology allows users to connect to the ISP at speeds comparable to DSL and cable?Wi-FisatelliteWiMAXMetro Ethernet10. A network administrator has changed the VLAN configurations on his network switches over the past weekend. How can the administrator determine if the additions and changes improved performance and availability on the company intranet?Conduct a performance test and compare with the baseline that was established previously.Interview departmental secretaries and determine if they think load time for web pages has improved.Determine performance on the intranet by monitoring load times of company web pages from remote sites.Compare the hit counts on the company web server for the current week to the values that were recorded in previous weeks.11.Refer to the exhibit. What is the meaning of the term dynamic in the output of the command?The bandwidth capability of the interface increases and decreases automatically based on BECNs.The Serial0/0/1 interface acquired 172.16.3.1 from a DHCP server.The mapping between DLCI 100 and 172.16.3.1 was learned through Inverse ARP.DLCI 100 will automatically adapt to changes in the Frame Relay cloud.12. Which type of ACL will permit traffic inbound into a private network only if an outbound session has already been established between the source and destination?extendedreflexivestandardtime-based13. Which two statements are true about IPv6 link local addresses? (Choose two.)They begin with the 2000::/3 prefix.They begin with the FE80::/10 prefix.They are assigned by IANA to an organization.They must be manually configured by the administrator.They are assigned to a host by a stateless autoconfiguration process.14. A company is looking for a WAN solution to connect its headquarters site to four remote sites. What are two advantages that dedicated leased lines provide compared to a shared Frame Relay solution? (Choose two.)reduced jitterreduced costsreduced latencythe ability to burst above guaranteed bandwidththe ability to borrow unused bandwidth from the leased lines of other customers15.Refer to the exhibit. A network administrator is trying to connect R1 remotely to make configuration changes. Based on the exhibited command output, what will be the result when attempting to connect to R1?failure to connect due to Telnet not being enabledfailure to connect due to incomplete configuration for Telneta successful connection and ability to make configuration changesa successful connection but inability to make configuration changes because of the absence of an enable secret password16. What are two effective measures for securing routers? (Choose two.)Protect all active router interfaces by configuring them as passive interfaces.Configure remote administration through VTY lines for Telnet access. Use quotes or phrases to create pass phrases.Disable the HTTP server service.Enable SNMP traps.17. An issue of response time has recently arisen on an application server. The new release of a software package has also been installed on the server. The configuration of the network has changed recently. To identify the problem, individuals from both teams responsible for the recent changes begin to investigate the source of the problem. Which statement applies to this situation?Scheduling will be easy if the network and software teams work independently.It will be difficult to isolate the problem if two teams are implementing changes independently.Results from changes will be easier to reconcile and document if each team works in isolation.Only results from the software package should be tested as the network is designed to accommodate the proposed software platform.Refer to the exhibit. From the output of the show interfaces and ping commands, at which layer of the OSI model is a fault indicated?applicationtransportnetworkdata linkphysical19. Which technology is used to dynamically map next hop, network layer addresses to virtual circuits in a Frame Relay network?Inverse ARPLMIDLCI20. An administrator learns of an e-mail that has been received by a number of users in the company. This e-mail appears to come from the office of the administrator. The e-mail asks the users to confirm their account and password information. Which type of security threat does this e-mail represent?crackingphishingphreakingspamming21.Refer to the exhibit. Which data transmission technology is being represented?TDMPPPHDLCSLIP22.Refer to the exhibit. Results of the show vlan and show vtp status commands for switches S1 and S2 are displayed in the exhibit. VLAN 11 was created on S1. Why is VLAN 11 missing from S2?There is a Layer 2 loop.The VTP domain names do not match.Only one switch can be in server mode.S2 has a higher spanning-tree priority for VLAN 11 than S1 does.23. What is the result of adding the global command servicepassword-encryption to the configuration of a router?Line passwords are encrypted with type 7 encryption.Enable passwords are encrypted with type 5 encryption.All services must provide an encrypted password to function.Only encrypted messages are allowed for router communication.24. While troubleshooting a problem with an e-mail server, an administrator observes that the switch port used by the server shows "up, line protocol up". The administrator cannot ping the server. At which layer of the OSI model is the problem most likely to be found?application layernetwork layerdata link layerphysical layer25. Where does a service provider assume responsibility from a customer for a WAN connection?local loopDTE cable on routerdemarcation pointdemilitarized zone26. What will be the result of adding the command ip dhcp excluded-address 192.168.24.1 192.168.24.5to the configuration of a local router that has been configured as a DHCP server?Traffic that is destined for 192.168.24.1 and 192.168.24.5 will be dropped by the router.Traffic will not be routed from clients with addresses between192.168.24.1 and 192.168.24.5.The DHCP server will not issue the addresses ranging from 192.168.24.1 to 192.168.24.5.The router will ignore all traffic that comes from the DHCP servers with addresses 192.168.24.1 and 192.168.24.5.27.Refer to the exhibit. Partial results of the show access-lists and show ip interface FastEthernet 0/1 commands for router Router1 are shown. There are no other ACLs in effect. Host A is unable to telnet to host B. Which action will correct the problem but still restrict other traffic between the two networks?Apply the ACL in the inbound direction.Apply the ACL on the FastEthernet 0/0 interface.Reverse the order of the TCP protocol statements in the ACL.Modify the second entry in the list to permit tcp host 172.16.10.10 any eq telnet .28.Refer to the exhibit. The corporate network that is shown has been assigned network 172.16.128.0/19 for use at branch office LANs. If VLSM is used, what mask should be used for addressing hosts at Branch4 with minimal waste from unused addresses?/19/20/21/22/23/2429.Refer to the exhibit. RIPv2 has been configured on all routers in the network. Routers R1 and R3 have not received any RIP routing updates. What will fix the issue?Enable RIP authentication on R2.Issue the ip directed-broadcast command on R2.Change the subnet masks to 10.11.12.0/8 and 172.16.40.0/16 on R2.Enable CDP on R2 so that the other routers will receive routing updates.30.Refer to the exhibit. This serial interface is not functioning correctly. Based on the output shown, what is the most likely cause?improper LMI typeinterface resetPPP negotiation failureunplugged cable31. Which statement is true about PAP in the authentication of a PPP session?PAP uses a two-way handshake.The password is unique and random.PAP conducts periodic password challenges.PAP uses MD5 hashing to keep the password secure.32. An administrator is configuring a dual stack router with IPv6 and IPv4 using RIPng. The administrator receives an error message when trying to enter the IPv4 routes into RIPng. What is the cause of the problem?When IPv4 and IPv6 are configured on the same interface, all IPv4 addresses are over-written in favor of the newer technology.Incorrect IPv4 addresses are entered on the router interfaces.RIPng is incompatible with dual-stack technology.IPv4 is incompatible with RIPng.33. What is tunneling?using digital certificates to ensure that data endpoints are authentic creating a hash to ensure the integrity of data as it traverses a networkusing alternate paths to avoid access control lists and bypass security measuresencapsulating an entire packet within another packet for transmission over a network34. Which statement is true about NCP?Link termination is the responsibility of NCP.Each network protocol has a corresponding NCP.NCP establishes the initial link between PPP devices.NCP tests the link to ensure that the link quality is sufficient. 35.Refer to the exhibit. A network administrator is creating a prototype to verify the new WAN design. However, the communication between the two routers cannot be established. Based on the output of the commands, what can be done to solve the problem?Replace the serial cable .Replace the WIC on RA.Configure RA with a clock rate command.Issue a no shutdown interface command on RB.36.Refer to the exhibit. Based on the output as shown, which two statements correctly define how the router will treat Telnet traffic that comes into interface FastEthernet 0/1? (Choose two).Telnet to 172.16.10.0/24 is denied.Telnet to 172.16.20.0/24 is denied.Telnet to 172.16.0.0/24 is permitted.Telnet to 172.16.10.0/24 is permitted.Telnet to 172.16.20.0/24 is permitted.37. Which Frame Relay flow control mechanism is used to signal routers that they should reduce the flow rate of frames?DEBECIRFECNCBIR38.Refer to the exhibit. A network administrator configures a standard access control list on Router1 to prohibit traffic from the 192.168.0.0/24 network from reaching the Internet. The access control list also permits traffic from the 192.168.0.0/24 network to reach the 192.168.1.0/24 network. On which interface and in which direction should the access control list be applied?interface Fa0/0, inboundinterface Fa0/0, outboundinterface S0/0/0, inboundinterface S0/0/0, outbound39. Which configuration on the vty lines provides the best security measure for network administrators to remotely access the core routers at headquarters?Answer: 3nd option 40.Refer to the exhibit. What can be concluded from the exhibited output of the debug ip nat command?The 10.1.1.225 host is exchanging packets with the 192.168.0.10 host.The native 10.1.200.254 address is being translated to 192.168.0.10.The 192.168.0.0/24 network is the inside network.Port address translation is in effect.41. A network administrator is instructing a technician on best practices for applying ACLs. Which suggestion should the administrator provide?Named ACLs are less efficient than numbered ACLs.Standard ACLs should be applied closest to the core layer.ACLs applied to outbound interfaces are the most efficient.Extended ACLs should be applied closest to the source that is specified by the ACL.42.Refer to the exhibit. Headquarters is connected through the Internet to branch office A and branch office B. Which WAN technology would be best suited to provide secure connectivity between headquarters and both branch offices?ATMVPNISDNFrame Relaybroadband DSL43. Which three physical network problems should be checked when a bottom-up troubleshooting approach has been chosen to troubleshoot network performance? (Choose three.)cable connectivityhigh collision countsSTP failures and loopsaddress mapping errorshigh CPU utilization ratesexcess packets that are filtered by the firewall44.Refer to the exhibit. A network administrator is attempting to configure a Frame Relay network. The administrator enters the commands as shown in the exhibit on R2, but the Frame Relay PVCs are inactive. What is the problem?The incorrect DLCI numbers are being configured on R2.The S0/0/0 interface on R2 needs to be point-to-point.The frame-relay map commands are missing the cisco keyword at the end.A single router interface cannot connect to more than one Frame Relay peer at a time.45. Which IP address and wildcard mask would be used in an ACL to block traffic from all hosts on the same subnet as host 192.168.16.43/28?access-list 10 deny 192.168.16.0 0.0.0.31access-list 10 deny 192.168.16.16 0.0.0.31access-list 10 deny 192.168.16.32 0.0.0.16access-list 10 deny 192.168.16.32 0.0.0.15access-list 10 deny 192.168.16.43 0.0.0.1646. Which combination of Layer 2 protocol and authentication should be used to establish a link without sending authentication information in plain text between a Cisco and a non-Cisco router?PPP with PAPPPP with CHAPHDLC with PAPHDLC with CHAP47. When would the multipoint keyword be used in Frame Relay PVCs configuration?when global DLCIs are in usewhen using physical interfaceswhen multicasts must be supportedwhen participating routers are in the same subnet48. A network technician analyzes the network and notices late collisions. The collisions occur accompanied by jabber that originates from the server. What is the likely cause of the problem?faulty switch portweb server CPU overloadfaulty NIC in the web servermisconfiguration of web server services49.Refer to the exhibit. R1 is performing NAT overload for the 10.1.1.0/24 inside network. Host A has sent a packet to the web server. What is the destination IP address of the return packet from the web server?10.1.1.2:1234172.30.20.1:1234172.30.20.1:3333192.168.1.2:8050.Refer to the exhibit. All devices are configured as shown in the exhibit. PC1 is unable to ping the default gateway. What is the cause of the problem?The default gateway is in the wrong subnet.STP has blocked the port that PC1 is connected to.Port Fa0/2 on S2 is assigned to the wrong VLAN.S2 has the wrong IP address assigned to the VLAN30 interface.51. When Frame Relay encapsulation is used, what feature provides flow control and exchanges information about the status of virtual circuits?LCPLMIDLCIInverse ARP52. A network administrator is tasked with maintaining two remote locations in the same city. Both locations use the same service provider and have the same service plan for DSL service. When comparing download rates, it is noticed that the location on the East side of town has a faster download rate than the location on the West side of town. How can this be explained?The West side has a high volume of POTS traffic.The West side of town is downloading larger packets.The service provider is closer to the location on the East side.More clients share a connection to the DSLAM on the West side.。
CCNA认证的考试步骤详解编者按:CISCO公司的职业资格证书CCNA在国外一向都有“通往高薪的直通车”的美誉,虽然在国内由于种种原因,CCNA已经不像前几年一样火爆,但其含金量还是为众多用人单位所重视,可以说,只要你手中有一份CCNA的有效证书(它的有效期为三年),那用人单位肯定会重点考察,成功的机率自然也就高出很多,然而更多的人对于CCNA根本不了解,或者只了解其中的一点点,尤其是关于考试的部分,更是大家所关心的,下面的内容就是告诉大家考试时的具体情况。
一、问卷调查考试系统分为VUE和Prometric两种,系统不同,开始的问卷调查内容也略有不同,但是不用担心,统选B相对安全,选完一道点NEXT,一直到END。
因为B选项通常表示考生水平一般,抽取的考题也不会太难。
注意:其中有一个调查是问你是否已满18周岁,一定要选已满18周岁。
最后一个调查是问你是否同意CISCO的协议,这个一定要选“同意”,如果您选“不同意”,那么你也就不用考试了。
曾经有位仁兄选了不同意,结果题目一直没有出现,一问考场,人家解释:你连CISCO的协议都不同意,你还考什么?不用考了。
要想再考,得再交一次考试费,重新注册这门考试。
协议过后,调查问卷页面右下角点END选项,考试系统自动开始从服务器抽取题目,题目前一天已由考试中心从澳洲下载完毕,暂存于服务器中。
数秒后,题目抽取完毕,考生可点START,正式考试开始。
二、正式考试同一考点同一天考同一科目的人,当天题目一般变化不会太大。
考试中,不允许标记和后退,一旦点击NEXT,则不可返回上一道试题修改。
题目为55-65道,中国是120分钟考试时间,1000分为满分,考到849分就通过。
考试时间很充足,第一次考试的人可能会紧张,其实只要准备充分,考试时间还是足够的,这一点可以放心。
题型多为客观选择题,单选或多选,一般选几个有提示,或告诉你选所有认为对的答案。
接下来是实验题,比如:让你使用相关命令,使网络配通,先在各个路由器上show run,。
CCNA 4 - Final Exam (C)Posted by beotron at 9:23 PM1. Which of the following describes the roles of devices in a WAN? (Choose three.)• A CSU/DSU terminates a digital local loop.• A modem terminates a digital local loop.• A CSU/DSU terminates an analog local loop.• A modem terminates an analog local loop.• A router is commonly considered a DTE device.• A router is commonly considered a DCE device.2. What value in the address field of a Frame Relay header identifies the destination of the frame? • CIR• DE• DLCI• ISDN• FRAD• PVC3. The serial PPP link between the Left and Right routers is configured as shown in the diagram. Which configuration issue explains why the link is unable to establish a PPP session?• The IP addresses must be on different subnets.• The usernames are misconfigured.• The passwords must be different for the CHAP authentication.• The clock rate must be 56000.• The clock rate is configured on the wrong end of the link.• Interface serial 0/0 on Left must connect to interface serial 0/1 on Right.4. The output of the show interfaces serial 0/0 command for a frame-relay connection indicates that the serial line is up but the line protocol is down. What are possible causes for this? (Choose two.)• There is an LMI-type mismatch between the Frame Relay switch and the router.• There is no clock present on the serial interface.• The interface is shut down.• RARP is not functioning on the router.• The cable is disconnected.5. Which statements are correct about the point in the network where the responsibility of the service provider ends? (Choose three.)• The International point is on the customer side of the network terminating unit(NTU).• The United States point is at the interface of the customer-provided equipment and the local loop.• The responsibility for this point is controlled by IANA.• The point is called the demarcation point.• The point is typically located at the service provider’s central office.• The point is located between the customer’s local area networks.6. While prototyping an internetwork in the corporate lab, a network administrator is testing a serial link between serial 0/0 interfaces on two routers. The labels on the serial cable ends have been damaged and are unreadable. What command can be issued to determine which router is connected to the DCE cable end?• show interfaces serial 0/0• show version• show controllers serial 0/0• show protocols serial 0/0• show status serial 0/07. A network technician determines DHCP clients are not working properly. The clients are receiving IP configuration information from a DHCP server configured on the router but cannot access the Internet. From the output in the graphic, what is the most likely problem?• The DHCP server service is not enabled.• The inside interface for DCHP is not defined.• The DHCP pool is not bound to the interface.• The pool does not have a default router defined for the clients.• All the host addresses have been excluded from the DHCP pool.8. A technician enters the interface serial 0/0.1 multipoint command when configuring a router. What effect will the multipoint keyword have in this configuration? (Choose two.)• Split-horizon issues will need to be resolved for this network if RIP is the routing protocol.• A subinterface will be defined for each PVC.• All the participating interfaces of remote routers will be configured in the same subnet.• A single DLCI will be used to define all the PVCs to the remote routers.• An IP address will need to be configured on the main interface.9. When configuring a Frame Relay connection, when should a static Frame Relay map be used? (Choose two.)• when the remote router is a non-Cisco router• whe n the remote router does not support Inverse ARP• when the local router is using IOS Release 11.1 or earlier• when broadcast traffic and multicast traffic over the PVC must be controlled• when globally significant rather than locally significant DLCIs a re being used10. Which router command would be used to associate a Layer 2 address with the corresponding Layer 3 address in the internetwork in the diagram?• RouterA(config-if)#frame-relay pvc 100 192.168.15.2• RouterA(config-if)#dialer-map ip 192.168.15.1 100 broadcast• RouterA(config-if)#frame-relay map ip 192.168.15.2 100 broadcast• RouterA (config-if)#dialer-map 192.168.15.1 101 serial 0 broadcast• RouterA (config-if)#frame-relay dlci 101 192.168.15.1 broadcast• RouterA (config-if)#dialer-map 192.168.15.1 inverse-arp broadcast11. Which of the following ISDN protocols is responsible for call setup and call teardown?• ITU-T Q.921• ITU-T Q.931• ITU-T I.430• ITU-T I.43112. What are two ways to resolve split-horizon issues in a Frame Relay network? (Choose two.)• create a full-mesh topology• disable Inverse ARP• use point-to-point subinterfaces• use multipoint subinterfaces• remove the broadcast keyword from the frame-relay map command13. What is the purpose of the command marked with an arrow shown in the partial configuration output of a Cisco 806 broadband router?• defines which addresses are allowed out of the router• defines which addresses are allowed into the router• defines which addresses can be translated• defines which address es are assigned to a NAT pool14. A system administrator is unable to ping the Serial0/0 interface of RouterB from RouterA. During the troubleshooting process, the following facts are established:- IP addressing and subnet masks are correct.- RouterA is a Cisco router and RouterB is a router from another vendor.- RouterA is configured with the default encapsulation.- The serial interfaces on both routers are up.- The protocol is down on the serial interfaces of both routers.What should the administrator do to solve the problem?• Add a clock rate on RouterA.• Enable the serial interface on RouterB.• Change the encapsulation on both routers to PPP.• Connect the serial cable to the correct interface on RouterB.• Use the correct serial cable to attach the CSU/DSU to RouterB.15. An ISDN circuit from a branch office is remaining connected to the regional office. A network administrator determines a user has initiated a continuous ping from a desktop computer to the regional office. Which configuration change would allow the ISDN circuit to disconnect during any attempts to ping, while otherwise functioning properly?• change DDR from legacy to dialer profiles• remove the dialer list statement from the configuration• change the dialer list to exclude IC MP as interesting• disable inverse ARP16. Below is a list of DDR steps. Which of the following identifies the proper order of DDR?1 - dial number is looked up2 - interesting traffic triggers DDR3 - route to destination is determined4 - call is made• 1,2,3,4• 1,3,2,4• 2,3,1,4• 2,1,3,4• 3,2,1,4• 3,1,2,417. Which protocol should be chosen to support WAN connectivity in a multi-vendor system and provide strong security through authentication?• NAT with DHCP• Frame Relay• HDLC with encryption• H DLC with CHAP• PPP with PAP• PPP with CHAP18. Which of the following are valid steps for a basic ISDN BRI configuration? (Choose two.)• create subinterfaces• define the LMI type• set the SPIDs if required by the ISDN switch• set the interface DLCI• set the switch type• specify the encapsulation as either Cisco or IETF19. A branch office reports excessive connect time charges for an ISDN circuit used to connect to the regional office. Upon investigation of this issue, it is discovered that when an ISDN connection is initiated to the regional office it remains connected for an excessive amount of time. Which of the following configuration changes could be made to DDR on the router to reduce these connect time charges?• use PPP multilink• lower idle timer setting• use CHAP authentication• change DDR from legacy to dialer profiles20. A network administrator is having difficulty in establishing a serial link between a Cisco router and a router from another vendor. Both routers are configured for HDLC encapsulation. Which statements are true regarding this configuration? (Choose two.)• The Cisco HDLC frame uses a proprietary “Type” field that may not be compatible with equipment of other vendors.• HDLC requires a clock rate to be configured on the r outers at both ends of the serial link.• PPP encapsulation is recommended for serial links between equipment from multiple vendors.• Usernames must be configured at both ends of the HDLC serial link.• The HDLC vendor type must be enabled on the Cisco ro uter.• There is a mismatch in the HDLC authentication password configurations.21. Given the partial router configuration in the graphic, why does the workstation with the IP address 192.168.1.153/28 fail to access the Internet? (Choose two.)• The NAT in side interfaces are not configured properly.• The NAT outside interface is not configured properly.• The router is not properly configured to use the access control list for NAT.• The NAT pool is not properly configured to use routable outside addresses.• The access control list does not include the IP address 192.168.1.153/28 to access the Internet.22. The serial PPP link between the Left and Right routers is configured as shown in the diagram. Which configuration issue will prevent IP traffic from crossing this link?• The passwords must be different for the CHAP authentication.• The usernames are misconfigured.• The clock rate must be 56000.• The clock rate is configured on the wrong end of the link.• The IP addresses must be on the same subnet.• Interface serial 0/0 on Left must connect to interface serial 0/1 on Right.23. What causes a DDR call to be placed?• dial string• DLCI• idle time out• interesting traffic• PVC24. Which two layers of the OSI model are described by WAN standards?• Application Layer, Physical Layer• Data Link Layer, Physical Layer• Data Link Layer, Transport Layer• Physical Layer, Network Layer25. A technician is testing RouterA in the graphic. What is the condition of the circuit?• The routers are configured fo r different encapsulations.• The clock rate is not properly configured on the routers.• The circuit from WAN provider has failed.• Authentication is not properly configured on the routers.• The circuit is functioning properly.26. A network administrator must provide WAN connectivity between a central office and three remote sites: Orlando, Atlanta, and Phoenix. The Orlando and Atlanta remote offices receive sales orders and transmit shipping confirmations to the Central office consistently throughout the day. The Phoenix remote office consists of one salesperson traveling through the southwest territory. The salesperson occasionally needs to connect to the Central office for e-mail access. How should the networkadministrator connect the remote sites to the Central office? (Choose two.)• Connect to the Atlanta and Orlando remote offices with Frame Relay connections.• Connect to the Atlanta and Orlando remote offices with ISDN connections.• Connect to the Atlanta and Orlando re mote offices with POTS dial-up connections.• Connect to the Phoenix remote office with a Frame Relay connection.• Connect to the Phoenix remote office with a POTS dial-up connection.27. When a Frame Relay switch detects an excessive buildup of frames in its queue, which of the following may occur? (Choose two.)• Frames with the DE bit set are dropped from the switch queue.• Frames with the FECN and BECN bits set are dropped from the switch queue.• Frames in excess of the CIR are not accepted by the sw itch.• The switch sets the FECN bit on all frames it places on the congested link and sets the BECN bit on all frames it receives on the congested link.• The switch sets the FECN bit on all frames it receives on the congested link and sets the BECN bit o n all frames it places on the congested link.28. A system administrator is troubleshooting a connectivity issue between two routers in a new installation. The administrator enters the debug ppp authentication command on the WHSE router. The graphic shows a part of the output received. From this output, what is the most likely cause of this connectivity issue?• There is not a route to the remote router.• The ISDN circuit on the remote router has failed.• The username/password was not properly configured on the WHSE router.• The remote router has a different authentication protocol configured.29. What does the output of the show frame-relay map command shown below represent? (Choose two.) • Serial 0 (up): ip 172.30.151.4 dlci 122, dynamic, broadcast, sta tus defined, active• 172.30.151.4 represents the IP address of the remote router.• 172.30.151.4 represents the IP address of the local serial interface.• DLCI 122 represents the interface of the remote router.• broadcast indicates that a dynamic routin g protocol such as RIP v1 can send packets across this PVC. • dynamic indicates that a dynamic routing protocol is enabled for this connection.• active indicates that the ARP process is working.30. What does the status inactive indicate in the output of the show frame-relay pvc command?• The DLCI is programmed in the switch but is not usable.• The DLCI was formerly programmed in the switch but is no longer there.• The DLCI is usable but has little activity.• The DLCI has been renamed for that PVC.31. Which of the following IP addresses are defined by RFC 1918 as private addresses? (Choose three.) • 192.168.146.0/22• 172.10.25.0/16• 172.31.0.0/16• 20.0.0.0/8• 10.172.92.8/2932. After configuring a dialup ISDN circuit, a network associate begins testing the dialup connection. When attempting to ping a host on the remote network, the local router does not attempt to dial the remote access server. Which of the following are possible errors in this configuration? (Choose three.) • PPP authentication is not properly configured.• No dialer map is configured.• The ISDN circuit connected to the remote access server is busy.• No interesting traffic is defined.• No route is determined to the remote network.• A wrong number is configured in the dial string.33. Two routers are connected through a Frame Relay, point-to-point PVC. The remote router is from a vendor other than Cisco. Which interface command is required to configure the link between the Cisco router and the other router?• frame-relay pvc multipoint• frame-relay pvc point-to-point• encapsulation frame-relay cisco• encapsulation frame-relay ietf• frame-relay lmi-type ansi34. Which circuit-switched WAN technology is often used to provide a backup for a leased line and additional capacity during peak usage times?• X.25• DSL• ISDN• cable modem35. After the ISDN BRI interface is configured, which command can be used to verify that the router is communicating correctly with the ISDN switch?• show dialer• show isdn status• show interfaces b ri0/0:1• show interfaces serial0/0.136. A system administrator needs to configure the regional office with ISDN for DDR connections to three remote sites. Each remote site requires different IP subnets, different encapsulations, and different authentication methods. The sites will not be connected at the same time. The company would like to accomplish this in the most cost effective manner. What method can the system administrator use to accomplish this task using the fewest B channels?• Install and conf igure a PRI.• Install and configure a BRI interface with separate SPIDs for each remote site.• Install and configure a BRI with multiple switch types in global configuration.• Install and configure a BRI using dialer profiles.• Install and configure a separate BRI for each remote site.37. A system administrator must provide Internet connectivity for ten hosts in a small remote office. The ISP has assigned two public IP addresses to this remote office. How can the system administrator configure the router to provide Internet access to all ten users at the same time?• Configure static NAT for all ten users.• Configure dynamic NAT for ten users.• Configure dynamic NAT with PAT.• Configure DHCP and static NAT.• What the administrator wants to do cannot be done.38. Which of the following are characteristics of Frame Relay? (Choose two.)• circuit-switched• connection oriented• OSI Layer 3• packet-switched• reliable39. Which of the following is the order for the three phases of establishing a PPP serial link with authentication?• authentication, link-establishment, network layer protocols• authentication, network layer protocols, link-establishment• network layer protocols, link-establishment, authentication• network layer protocols, authenticati on, link-establishment• link-establishment, authentication, network layer protocols• link-establishment, network layer protocols, authentication。
1What are two characteristics of DSL technology? (Choose two.)Uploads typically offer larger transfer rates than downloads.Service providers deploy DSL in the local loop of the telephone network.DSL download rates are reduced by large volumes of POTS voice traffic.Filters and splitters allow POTS and DSL traffic to share the same medium.DSL is a shared medium that allows many users to share bandwidth available from the DSLAM.2When configuring remote access to a router, what is the significance of the no password command on a VTY line?Logins are prevented on that line.No password is required to log in to that line.The remote user is not allowed to change the password for that line.The remote user is prompted to change the line password after connecting to the router.3Which three items are LCP options that can be configured for PPP? (Choose three.)CHAPStackerIPCPCDPCPMultilink4An administrator is unable to receive e-mail. While troubleshooting the problem, the administrator is able to ping the local m address successfully from a remote network and can successfully resolve the mail server name to an IP address via th e us nslookup command. At what layer of the OSI model is the problem most likely to be found?applicationtransportnetworkdata link5Which combination of Layer 2 protocol and authentication should be used to establish a link between a Cisco and a non-Ci without sending authentication information in plain text?HDLC with PAPHDLC with CHAPPPP with PAPPPP with CHAP6At what physical location does the responsibility for a WAN connection change from the service provider to the user?DMZlocal loopCSU/DSUdemarcation point7Refer to the exhibit. An ACL numbered 101 already exists on this router. What happens if the network administrator issues commands that are shown in the exhibit?The new ACL overwrites the existing ACL.The network administrator will receive an error message.The existing ACL is modified to include the new commands.A second ACL that is numbered 101 is created and contains only the new commands.8Which important piece of troubleshooting information can be discovered about a serial interface using the show controllersqueuing strategyserial cable typeinterface IP addressencapsulation method9Refer to the exhibit. A network administrator is using two routers to test a WAN connection . What can be concluded based o of the show running-config commands?The WAN link is using PPP encapsulation.The WAN link speed is faster than a T1 line.The router R2 serves as the DCE for the WAN link.The WAN link is configured with the Cisco default encapsulation protocol.10Refer to the exhibit. The corporate network that is shown has been assigned network 172.16.128.0/19 for use at branch off VLSM is not being used. Which subnet mask will allow the most efficient utilization of IP addresses?/21/22/23/24/25/2611 A company uses a PVC with a committed information rate (CIR) of 128 kb/s and a committed burst information rate (CBIR)The link is used to periodically send updates at a rate of 144 kb/s. What will happen to the update traffic?The traffic will be sent, but the company will be charged a penalty.The traffic will be sent using the additional CBIR and will be guaranteed delivery.The traffic will be dropped at the CO for exceeding the committed information rate.The traffic will be sent, but the burst traffic will be marked for discard if congestion is encountered.12Which wildcard mask would specify all IP addresses from 192.168.8.0 through 192.168.15.255?0.0.0.70.0.7.2550.0.8.2550.0.15.2550.0.255.25513Refer to the exhibit. An administrator has added the exhibited commands to routers A and B, but no routing updates are ex between the two routers. Based on the information that is given, what is the likely cause of the problem?Router A is advertising the wrong network.The authentication key strings do not match.The serial interfaces of routers A and B are not on the same network.The authentication key numbers do not match the EIGRP process number for both routers.14Refer to the exhibit. A network technician has been called in to resolve a problem with this network segment. The symptom loss of connectivity throughout the network segment, high link utilization, and syslog messages that indicate constant MAC relearning. What is the likely cause of these symptoms?cable faultfaulty NIC cardIP addressing errorspanning tree problemNAT configuration error15Refer to the exhibit. The SSH connections between the remote user and the server are failing. The correct configuration of been verified. What is the most likely cause of the problem?SSH is unable to pass through NAT.There are incorrect access control list entries.The access list has the incorrect port number for SSH.The ip helper command is required on S0/0/0 to allow inbound connections.16Refer to the exhibit. Which two statements correctly describe how Router1 processes an FTP request that enters interface destined for an FTP server at IP address 192.168.1.5? (Choose two.)The packet does not match an access list condition.The router matches the incoming packet to the statement that is created from the access-list 201 permit ip any anyThe router matches the incoming packet to the statement that is created from the access-list 101 permit ip any 192.0.0.0.255 command.The router matches the incoming packet to the statement that is created from the access-list 201 deny icmp 192.1680.0.0.255 any17Refer to the exhibit. Which statement is true about the WAN switch device?It uses a multiport internetworking device to switch traffic such as Frame Relay, ATM or X.25 over the WAN.It provides internetworking and WAN access interface ports that are used to connect to the service provider network.It provides termination for the digital signal and ensures connection integrity through error correction and line monitorinIt converts the digital signals produced by a computer into voice frequencies that can be transmitted over the analog l public telephone network.18Refer to the exhibit. You are a network administrator who has been tasked with completing the Frame Relay topology that in two remote sites. How should the point-to-point subinterfaces be configured on HQ to complete the topology?HQ(config-subif)#frame-relay interface-dlci 103 on Serial 0/0/0.1HQ(config-subif)#frame-relay interface-dlci 203 on Serial 0/0/0.2HQ(config-subif)#frame-relay interface-dlci 301 on Serial 0/0/0.1HQ(config-subif)# frame-relay interface-dlci 302 on Serial 0/0/0.2HQ(config-subif)#frame-relay map ip 172.16.1.1 103 broadcast on Serial 0/0/0.1HQ(config-subif)#frame-relay map ip 172.16.2.2 203 broadcast on Serial 0/0/0.2HQ(config-subif)#frame-relay map ip 172.16.1.1 301 broadcast on Serial 0/0/0.1HQ(config-subif)#frame-relay map ip 172.16.2.2 302 broadcast on Serial 0/0/0.219What effect would the Router1(config-ext-nacl)# permit tcp 172.16.4.0 0.0.0.255 any eq www command have when implem inbound on the f0/0 interface?All TCP traffic is permitted, and all other traffic is denied.The command is rejected by the router because it is incomplete.All traffic from 172.16.4.0/24 is permitted anywhere on any port.Traffic originating from 172.16.4.0/24 is permitted to all TCP port 80 destinations.20What is a major characteristic of a worm?malicious software that copies itself into other executable programstricks users into running the infected softwarea set of computer instructions that lies dormant until triggered by a specific eventexploits vulnerabilities with the intent of propagating itself across a network21At what point in the PPP connection process does the authentication phase occur?after NCP establishes Layer 3 parametersbefore LCP begins the link establishment processafter the initial Configure-Request message from the link initiatorafter the link initiator receives a Configure-Ack message from the responder22Refer to the exhibit. What is placed in the address field in the header of a frame that will travel from the DC office of ABC C the Orlando office?MAC address of the Orlando routerMAC address of the DC router192.168.1.25192.168.1.26DLCI 100DLCI 20023What is the function of an IDS?to report the attack after it happensto stop the attack prior to its completionto quarantine the virus or worm so as not to infect any other hostto reconfigure the security policy of a firewall to prevent another attack24 A network administrator added two switches and a new VLAN over the past weekend. How can the administrator determineadditions and changes improved performance and availability on the company intranet?Perform a baseline test and compare the current values to values that were obtained in previous weeks.Interview departmental secretaries and determine if they think load time for web pages is improved.Compare the hit counts on the company web server for the current week to the values that were recorded from previoPerformance on the intranet can be determined by monitoring load times of company web pages from remote sites. 25Refer to the exhibit. In the partial router configuration that is shown, what is the purpose of access list BLOCK_XYZ?to prevent source IP address spoofing by hosts on the Fa0/0 LANto block access by Fa0/0 LAN hosts to all network services beyond the routerto prevent users on the Fa0/0 LAN from opening Telnet sessions on the routerto secure Fa0/0 hosts by allowing only locally sourced traffic into the Fa0/0 LAN26Which wireless solution can provide mobile users with non line-of-sight broadband Internet access at speeds comparable t cable?Wi-FiWiMAXsatelliteMetro Ethernet27What does an access control list determine when used with NAT on a Cisco router?addresses that are to be translatedaddresses that are assigned to a NAT pooladdresses that are allowed out of the routeraddresses that are accessible from the inside network28Refer to the exhibit. What is the effect of the extended ACL when applied inbound on the S0/0/0 interface on R2?All IP traffic will be permitted during the specified days and time range.Both IP and Telnet traffic will be permitted during the specified days and time range.Only Telnet traffic destined for 172.16.10.0/24 will be permitted during the specified days and time range.Telnet traffic will be permitted only during the specified days and time range. All other network traffic w ill be permitted 29Which statement is true about an interface that is configured with the IPv6 address command?IPv6 traffic-forwarding is enabled on the interface.A link-local IPv6 address is automatically configured on the interface.A global unicast IPv6 address is dynamically configured the interface.Any IPv4 addresses that are assigned to the interface are replaced with an IPv6 address.30Refer to the exhibit. Which statement is true about the status of the Frame Relay connection?The Frame Relay connection is in the process of negotiation.Only packets with control bit DE set are sent over the PVC. No data traffic traverses the link.Packets marked as FECN and BECN indicate that a congestion control mechanism is enabled on the Frame Relay PVThe “DLCI USAGE = LOCAL” status indicates that the PVC link is not established between the interface S0/0/0.1 and Relay switch.31What three statements describe the roles of devices in a WAN? (Choose three.)A CSU/DSU terminates a digital local loop.A modem terminates a digital local loop.A CSU/DSU terminates an analog local loop.A modem terminates an analog local loop.A router is commonly considered a DTE device.A router is commonly considered a DCE device.32 A company has its headquarters office in Dallas and five branch offices located in New York, Chicago, Los Angeles, SeattlAtlanta. WAN links are used for communications among offices in six sites. In planning the WAN links, the network designe requirements: (1) minimize cost and (2) provide a certain level of WAN link reliabili ty with redundant links. Which topology s network designer recommend?starfull meshhierarchicalpartial mesh33Which address provides an example of an IPv6 link-local address?FE80::1324:ABCD2001:2345:AB12:1935::FEFF2001:1234:0000:9CA::0876/641234:ABCD:5678:EF00:9234:AA22:5527:FC3534Refer to the exhibit. The network administrator creates a standard access control list to prohibit traffic from the 192.168.1.0 from reaching the 192.168.2.0/24 network while still permitting Internet access for all networks. On which router interface a direction should it be applied?interface fa0/0/0, inboundinterface fa0/0/0, outboundinterface fa0/0/1, inboundinterface fa0/0/1, outbound35 A network technician accidentally deleted the IOS image from flash and rebooted the router. Which two options can be usethe IOS image? (Choose two.)Perform a system restore through SDM.Download the image from a TFTP server through a network connection.Download the image from a TFTP server through a console connection.Establish an FTP session through an SSH connection for the image download.Use the Xmodem protocol to download the image through a console connection.36Refer to the exhibit. A packet is being sent from Host A to Host B through the VPN tunnel between R1 and R3. When the p arrives at R3, what are the source and destination IP addresses of the packet?Source 192.168.1.2 - Destination 192.168.4.2Source 192.168.3.1 - Destination 192.168.3.2Source 192.168.2.1 - Destination 192.168.3.2Source 192.168.3.1 - Destination 192.168.4.237Refer to the exhibit. Router1 and Router2 each support separate areas of a data center, and are connected via a crossover Resources attached to Router1 are unable to connect to resources attached to Router2. What is the likely cause?The crossover cable is faulty.The IP addressing is incorrect.There is a Layer 2 problem with the router connection.The upper layers are experiencing an unspecified problem.One or both of the Ethernet interfaces are not working correctly.38Which two functions are provided by the Local Management Interface (LMI) that is used in Frame Relay networks? (Choosflow controlerror notificationcongestion notificationthe mapping of DLCIs to network addressesthe sending of keepalive packets to verify operation of the PVC39What will be the result of adding the command ip dhcp excluded-address 172.16.4.1 172.16.4.5 to the configuration of a that has been configured as a DHCP server?Traffic that is destined for 172.16.4.1 and 172.16.4.5 will be dropped by the router.Traffic will not be routed from clients with addresses between 172.16.4.1 and 172.16.4.5.The DHCP server function of the router will not issue the addresses between 172.16.4.1 and 172.16.4.5.The router will ignore all traffic that comes from the DHCP servers with addresses 172.16.4.1 and 172.16.4.5.40Refer to the exhibit. A network administrator is trying to backup the IOS software on R1 to the TFTP server. He receives th message that is shown in the exhibit, and cannot ping the TFTP server from R1. What action can help to isolate this probleCheck that R1 has a route to the 10.10.10.0 network.Verify that the TFTP server software supports binary file transfers.Make sure that the TFTP server has 192.168.1.1 as its default gateway.Ensure that the laptop has an IP address in the 192.168.1.0/24 network.41Refer to the exhibit. Branch A has a Cisco router. Branch B has a non-Cisco router set for IETF encapsulation. After the co shown are entered, R2 and R3 fail to establish the PVC. The R2 LMI is Cisco, and the R3 LMI is ANSI. The LMI is success established at both locations. Why is the PVC failing?The PVC to R3 must be point-to-point.LMI types must match on each end of a PVC.The ietf parameter is missing from the frame-relay map ip 10.10.10.3 203 command.The PVCs at R2 use different encapsulation types. A single port can only support one encapsulation type.42Refer to the exhibit. Why are the routers unable to establish a PPP session?The usernames are misconfigured.The IP addresses are on different subnets.The clock rate is configured on the wrong end of the link.The CHAP passwords must be different on the two routers.Interface serial 0/0/0 on Router1 must connect to interface serial 0/0/1 on Router2.43 A system administrator must provide Internet connectivity for ten hosts in a small remote office. The ISP has assigned twoaddresses to this remote office. How can the system administrator configure the router to provide Internet access to all ten same time?Configure static NAT.Configure dynamic NAT.Configure static NAT with overload.Configure dynamic NAT with overload.44While configuring a router using RIPng and dual-stack technology with IPv4 and IPv6, the administrator receives an error m inputting IPv4 routes. What could cause the error message?IPv4 is not compatible with RIPngRIPng is incompatible with dual-stack technology.The router interfaces have been configured with incorrect addresses.When IPv4 and IPv6 are configured on the same interface, all IPv4 addresses are shut down in favor of the newer tec 45What will be the result of the enable secret command when added at the global configuration mode on the router?It will use MD5 encryption to protect the privileged EXEC level access.It will use type 7 encryption and will encrypt only the privileged EXEC level passwords.It will use type 7 encryption to prevent all passwords that are displayed on the screen from being readable.It will use MD5 encryption to protect the passwords that are only used in the PAP and CHAP authentication process. 46Refer to the exhibit. Which VLAN will carry untagged traffic on FastEthernet 0/1?VLAN 1VLAN 2VLAN 11VLAN 12VLAN 30VLAN 99947Refer to the exhibit. A technician is teaching a trainee to interpret the results of various Frame Relay troubleshooting comm conclusion can be drawn from the output that is shown?Neighboring routers should use DLCI 177 to reach the Branch router.DLCI 177 will be used to identify all broadcasts that are sent out the Branch router.The Branch router has the address 192.168.3.1 configured for the S0/0/0 interface.To reach 192.168.3.1, the Branch router will use the virtual circuit that is identified by DLCI 177.48Refer to the exhibit. What would be the result of entering the exhibited configuration on a Frame Relay router?The local interface DLCI will be set to 102.All traffic that is destined to 172.16.16.8 will be sent as broadcast.Only broadcast traffic will be recieved on the Frame Relay interface.Routing protocol multicast updates can be forwarded across the Frame Relay PVC.49Refer to the exhibit. Routers R1 and R2 are both configured for single area OSPF. Users who are connected to switch S1 a access database applications that run on servers that are connected to S2. The network engineer is working remotely and information that is shown in the exhibit to direct initial troubleshooting efforts. Based on the exhibit, which OSI layer is the m appropriate to start with for a divide-and-conquer approach?network layerapplication layerdata-link layerphysical layer50Refer to the exhibit. A host that is connected to Fa0/0 is unable to acquire an IP address dynamically from the DHCP server. The output of the debug ip dhcp server command shows "DHCPD: there is no address pool for 172.16.1.1".What is the problem?The default router for the 172Network pool is incorrect.The 172.16.1.1 address is already configured on Fa0/0.The pool of addresses for the 172Network pool is incorrect.The ip helper-address command should be implemented on the Fa0/0 interface.。