2021思科認(rèn)證歷年真題6章

2021思科認(rèn)證歷年真題6章第1章

什么命令允許你查看RAM中的配置()

A.showstartup-config

B.showRAM-config

C.showrunning-config

D.showconfig

正確答案：C

-臺運(yùn)行OSPF的路由器，它的兩個正常工作的接口一個屬于區(qū)域0,另一個

屬于區(qū)域9,并且重分布5條靜態(tài)路由進(jìn)入OSPF,則該路由器一定會始發(fā)哪些

LSA()

A.RouterLSA(Type=l)；

B.NetworkLSA(Type=2)；

C.NetworkSummaryLSA(Type=3)；

D.ASBRSummaryLSA(Type=4)；

E.ASExternalLSA(Type=5)；

正確答案：ACDE

IP地址為：0,掩碼為:255,255.255,248,則該IP地址所在子網(wǎng)

的子網(wǎng)號為()

A.2

B.4

C6

D.1

正確答案：B

對于以下ACL語句描述正確的是()

RI(config)#ipaccess-liststandardTELNET

RI(config_stdTiacl)#perinit

R1(c^ifig)#1ineyty04

RI(config-1ine)#access-classTELNETin

A.只允許的數(shù)據(jù)流穿過RI

B.只允許對RI進(jìn)行TELNET

C.只允許對RI進(jìn)行TELNET并拒絕其它流量

D.只允許/24網(wǎng)段的數(shù)據(jù)流穿過R1

正確答案：B

要顯示由產(chǎn)品ID和路由器序列號組成的唯一設(shè)備標(biāo)識符，可使用哪個命令?()

A.showlicense

B.showlicensefeature

C.showlicenseudi

D.showversion

答案：C

2021思科認(rèn)證歷年真題6章第2章

Duringthebootsequence,aEzonexam2800seriesrouterneedstolocate

andloadanoperatingsystem.Whatisthedefaultordertherouterusestofind

anoperatingsystem?

A.ROM,TFTPserver,Flash

B.Flash,TFTPserver,ROM

C.Flash,NVRAM,TFTPserver

D.Flash,ROM,TFTPserver

E.Flash,TFTPserver,RAM

正確答案：B

解析：

Explanation:BootinguptheRouter:CiscorouterscanbootCiscoIOSsoftwarefromthese

locations:!.Flashmemory2.TFTPserver3.ROM(notfullCiscoIOS)Multiplesourceoptio

nsprovideflexibilityandfallbackalternatives.

PPP驗(yàn)證可選的驗(yàn)證方式有0。

A.MD5

B.PAP

C.CHAP

DJPSec

正確答案：BC

RIP路由協(xié)議每隔()秒進(jìn)行路由更新。

A.30

B.60

C.120

D.180

正確答案：A

把訪問權(quán)限表應(yīng)用到路由器端口的命令是：()

A.permitaccess-list101out

B.ipaccess-group101out

C.applyaccess-list101out

D.access-class101out

正確答案：B

請參見圖示圖中顯示了在路由器R1上發(fā)出showiproute命令后的輸出對于

發(fā)往的數(shù)據(jù)包，該路由器會采取什么操作()

Ri#showiprowte

Codes:C-connected/S-static，I-IGRf,R-RIP.M-Mobile?B-BGF

D-E1GFP,EX-external,0?OSIP,U-03”intecarea

VI?05FFVSSAextetnaltypeA,N2?OSFFV3SAextetnaltype2

EI-OSPFexternaltype1.E2?OSFFexternaltype2,■?EGP

1-IS-I34LI-IS-I5L2-IS-I3la-IS-ISint?K3”

?-cgdidasdeteult,U-pec-u9eco-

T-periodicdownloadedvtatictout*

Getevayof19ttesoctisnotset

/24issubnetted/3subaetj

S(1/0]via

Cisdictcdycomecttd,SetialO/O/O

C1*dicecclycomected,FaJtEthernetO/0

S/24[1/0]via

S/24isdlzectlyconnecs%S<Klal0/0/0

Sw/0isditecclyconnected,FajtEthemec0/0

5-

A.它會丟棄數(shù)據(jù)包

B.它會將數(shù)據(jù)包轉(zhuǎn)發(fā)到接口Serial0/0/0

c.它會通過路由協(xié)議為數(shù)據(jù)包確定路由

D.它會將數(shù)據(jù)包轉(zhuǎn)發(fā)到默認(rèn)網(wǎng)關(guān)

正確答案：B

2021思科認(rèn)證歷年真題6章第3章

在大型網(wǎng)絡(luò)中選擇OSPF而不選擇RIP的原因是（）

A.更快的路由收斂

B.需要更少的路由器內(nèi)存

C.需要更少的CPU的資源

D.更優(yōu)的選路，路由無環(huán)路

正確答案：AD

ThenetworkadministratorhasconfiguredportsecurityonaEzonexam

switch.Whywouldanetworkadministratorconfigureportsecurityonthis

Ezonexamdevice?

A.TopreventunauthorizedhostsfromgettingaccesstotheLAN

B.TolimitthenumberofLayer2broadcastsonaparticularswitchport

C.TopreventunauthorizedTelnetorSSHaccesstoaswitchport

D.TopreventtheIPandMACaddressoftheswitchandassociatedports

E.Noneoftheabove

正確答案：A

解析：Explanation:

Youcanusetheportsecurityfeaturetorestrictinputtoaninterfacebylimiting

andidentifyingMACaddressesofthestationsallowedtoaccesstheport.When

youassignsecureMACaddressestoasecureport,theportdoesnotforward

packetswithsourceaddressesoutsidethegroupofdefinedaddresses.Ifyou

limitthenumberofsecureMACaddressestooneandassignasinglesecure

MACaddress,theworkstationattachedtothatportisassuredthefullbandwidth

oftheport.

IfaportisconfiguredasasecureportandthemaximumnumberofsecureMAC

addressesisreached,whentheMACaddressofastationattemptingtoaccess

theportisdifferentfromanyoftheidentifiedsecureMACaddresses,asecurity

violationoccurs.Also,ifastationwithasecureMACaddressconfiguredor

learnedononesecureportattemptstoaccessanothersecureport,aviolationis

flagged.

Youneedtoconfigurean802.IQlinkonaEzonexamswitch.Which

commands,whenusedtogether,woulddothis?(Selecttwoanswerchoices)

A.Switch(vlan)modetrunk

B.Switch(config)switchportaccessmodetrunk

C.Switch(config-if)switchportmodetrunk

D.Switch(config-if)switchporttrunkencapsulationdotlq

E.Switch(config)switchportaccessmode1

F.Switch(vlan)trunkencapsulationdotlq

正確答案：CD

C,D解析：Explanation:

Creatingthistrunklinkisatwostepprocess.Firstyouhavetosettheswitchport

modetotrunk,andthenyouconfiguretheencapsulation.Thegiveawayonthis

questionisthefactthattocreateatrunkonaninterface,youhavetobein

interfaceconfigurationmode.Soswitchportmodetrunksetsthetrunk,and

switchporttrunkencapsulationdotlqsetstheencapsulation.

Youneedtodecideonwhichtrunkingmethodtoimplementinthe

Ezonexamnetwork.WhatisacharacteristicofISLand802.1qframe,taggingina

switchedLANenvironment?

A.Theyareusedtofindthebestpaththroughanetwork.

B.Theyallowtheexchangeoffilteringtables.

C.TheyspecifydifferentimplementationsoftheSpanning-TreeProtocol.

D.Theyallowtheexchangeofroutingtables

E.Theyprovideinter-switchVLANcommunication.

正確答案：E

解析:Explanation:AtrunklinkistheothertypeofLayer2portsupportedon

Ciscoswitches.Whenatrunkportisconfigured,itbeginsmarkingframesasthey

exittheporttoindicatewhichVLANeachframe,isassociatedwith.

Thetrunkportcanalsoreadthemarkings,calledtags,astheyenterthetrunk

port.Thisenablestheswitchtosendaframe,onlytotheportsforthegiven

VLANassociatedwiththeincomingframe.Themainpurposeoftrunkingisto

carrytrafficbetweenswitchesandmaintaintheVLANinformation.

Unlikeanaccesslink,thetrunklinkdoesnotbelongtoasingleVLANbutinstead

cancarrytrafficfromseveralVLANsoverapoint-to-pointlinkbetweentwo

devicesthatunderstandtheprotocol.TwoformsoftrunkingareusedforCisco

switchesonEthernetnetworks:AnIEEEindustrystandardcalledIEEE802.IQ.

Thisisaframe-taggingmechanismthataddsaVLANidentifiertotheframe.by

insertingatagatLayer2.Anotherform.oftrunkingonCiscoswitchesiscalled

Inter-SwitchLinkQSL),whichisaCiscoproprietarytrunkingmechanism.ISLuses

aframe.encapsulationmethodthataddsaheadertoidentifytheVLAN.

IncorrectAnswers:

A,D.Thesearethefunctionsofrouters,notswitches.

B.FilteringtablescanbeusedoncertainCatalystswitchesviatheuseofVLAN

accesscontrollists,butthisinformationisneversharedbetweenswitches.

C.AseparateSTPinstanceiscreatedforeachVLAN；buttheSTPimplementation

remainsthesame.

要確保交換機(jī)成為VLAN30的根網(wǎng)橋，可使用下面哪兩個命令之一?()

A.spanning-treevlan30priority0

B.spanning-treevlan30priority16384

C.spanning-treevlan30rootguarantee

D.spanning-treevlan30rootprimary

答案：AD

2021思科認(rèn)證歷年真題6章第4章

命令ipnatpoolaaa0netmask的作用是()

A.指定可訪問地址

B.定義地址池

C.指定路由

D.定義哪些地址可以進(jìn)行地址轉(zhuǎn)換

正確答案：B

YouwanttoinfluencetherootbridgeselectionwithintheEzonexamLAN.

Whichtwovaluesareusedbyspanningtreeprotocoltoelectarootbridge?

(Choosetwo.)

A.AmountofRAM

B.Speedofthelinks

C.IOSVersion

D.MACAddress

E.BridgePriority

F.IPAddress

G.RouterID

正確答案：DE

D,E

Areceivinghosthasfailedtoreceiveallofthesegmentsthatitshould

acknowledge.

Whatcanthehostdotoimprovethereliabilityofthiscommunication

session?

A.StartanewsessionusingUDP

B.ObtainanewIPaddressfromtheDHCPserver

C.Useadifferentsourceportforthesession

D.Decreasethesequencenumber

E.Decreasethewindowsize

正確答案：E

解析:Explanation:

ATCPwindowtheamountofoutstanding(unacknowledgedbytherecipient)

dataasendercansendonaparticularconnectionbeforeitgetsan

acknowledgmentbackfromthereceiverthatithasgottensomeofit.

ForexampleifapairofhostsaretalkingoveraTCPconnectionthathasaTCP

windowsizeof64KB(kilobytes),thesendercanonlysend64KBofdataandthen

itmuststopandwaitforanacknowledgmentfromthereceiverthatsomeorall

ofthedatahasbeenreceived.Ifthereceiveracknowledgesthatallthedatahas

beenreceivedthenthesenderisfreetosendanother64KB.

OnewaytoimprovethereliabilityoftheTCPconnectionistoreducethewindow

sizethatthereceiverneedstoreceivebeforesendinganacknowledgement.

However,thiswillreducethroughputasmoresegmentsandacknowledgements

willneedtobesentinordertotransferthesameamountofdata.

介質(zhì)工作在OSI的哪一層（）

A物理層

B.數(shù)據(jù)鏈路層

C.網(wǎng)絡(luò)層

D.傳輸層

正確答案：A

請參見圖示。公司的新安全策略允許來自工程部LAN的所有IP流量訪問

Internet,但對于來自營銷部LAN的流量，則只允許其中的web流量訪問

Internet,.為實(shí)施新的安全策略，可在營銷部路由器的SerialO/1接口的出站方向上

應(yīng)用哪一ACLQ

A.access-list197permitip55anyaccess-list197permitip

55anyeqwww

B.access-list165permitip55anyaccess-list165permittcp

55anyeqwwwaccess-list165permitipanyany

C.access-list137permitip55anyaccess-list137permittcp

55anyeqwww

D.access-list89permit55anyaccess-list89permittcp

55anyeqwww

正確答案：C

2021思科認(rèn)證歷年真題6章第5章

RIP的管理距離為()。

A.0

B.l

C.110

D.120

正確答案：D

你使用命令copyrunning-configstartup-config保存路由器的配置，并重啟路由

器，但路由器啟動后沒有任何運(yùn)行配置。請問可能出現(xiàn)了什么問題?()

A.啟動路由器時使用的命令不對

B.NVRAM受損

G配置寄存器的設(shè)置不正確

D.新升級到的IOS與路由器硬件不兼容

E.保存的配置與硬件不兼容

答案：C

下列對訪問控制列表的描述不正確的是()。

A.訪問控制列表能決定數(shù)據(jù)是否可以到達(dá)某處

B.訪問控制列表可以用來定義某些過濾器

C.一旦定義了訪問控制列表，則其所規(guī)范的某些數(shù)據(jù)包就會嚴(yán)格被允許或拒絕

D.訪問控制列表可以應(yīng)用于路由更新的過程當(dāng)中

正確答案：D

基本IP訪問權(quán)限表的表號范圍是：（）

A.1—100

B.1-99

C.100-199

D.800-899

正確答案：B

AtwhichOSIlayerisalogicalpathcreatedbetweentwohostsystemsnamed

VE1andVE2ontheEzonexamLAN?

A.Physical

B.Session

C.Datalink

D.Transport

E.Network

F.Application

G.Presentation

正確答案：E

E

2021思科認(rèn)證歷年真題6章第6章

TheEzonexamnetworkadministratorneedstoaswitchnamedVE1to

becometherootbridgeforaredundantpathswitchednetwork.Whatcanbe

donetoensurethatVE1willalwaysassumetheroleastherootbridge?

A.AssigntheswitchahigherMACaddressthantheotherswitchesinthe

networkhave

B.Establishadirectlinkfromtheswitchtoallotherswitchesinthenetwork

C.Configuretheswitchfull-duplexoperationandconfiguretheother

switchesforhalf-duplexoperation

D?Configuretheswitchsothatithaslowerprioritythanotherswitchesin

thenetwork

E.Noneoftheabove

正確答案：D

AEzonexamswitchisconfiguredwithallportsassignedtoVLAN2.In

addition,allportsareconfiguredasfull-duplexFastEthernet.Whatistheeffectof

addingswitchportstoanewVLANonthisswitch?

A.Theadditionswillcreatemorecollisionsdomains.

B.IPaddressutilizationwillbemoreefficient.

C.Morebandwidthwillberequiredthanwasneededpreviously.

D.Anadditionalbroadcastdomainwillbecreated.

E.Thepossibilitythatswitchingloopswilloccurwillincreasedramatically.

正確答案：D

解析：Explanation:

AVLANisagroupofhostswithacommonsetofrequirementsthat

communicateasiftheywereattachedtothesamewire,regardlessoftheir

physicallocation.AVLANhasthesameattributesasaphysicalLAN,butitallows

forendstationstobegroupedtogethereveniftheyarenotlocatedonthesame

LANsegment.

Networksthatusethecampus-wideorend-to-endVLANslogicallysegmenta

switchednetworkbasedonthefunctionsofanorganization,projectteams,or

applicationsratherthanonaphysicalorgeographicalbasis.Forexample,all

workstationsandserversusedbyaparticularworkgroupcanbeconnectedtothe

sameVLAN,regardlessoftheirphysicalnetworkconnectionsorinteractionwith

otherworkgroups.

Networkreconfigurationcanbedonethroughsoftwareinsteadofphysically

relocatingdevices.CiscorecommendstheuseoflocalorgeographicVLANsthat

segmentthenetworkbasedonIPsubnets.Eachwiringclosetswitchisonitsown

VLANorsubnetandtrafficbetweeneachswitchisroutedbytherouter.The

reasonsfortheDistributionLayer3switchandexamplesofalargernetwork

usingboththecampus-wideandlocalVLANmodelswillbediscussedlater.

AVLANcanbethoughtofasabroadcastdomainthatexistswithinadefinedset

ofswitches.PortsonaswitchcanbegroupedintoVLANsinordertolimit

unicastmulticast,andbroadcasttrafficflooding.Floodedtrafficoriginatingfrom

aparticularVLANisonlyfloodedoutportsbelongingtothatVLAN,including

trunkports,soaswitchthatconnectstoanotherswitchwillnormallyintroduce

anadditionalbroadcastdomain.

ICMPisoftenusedintroubleshootingandverifyingnetwork.What

statementsaretrueregardingICMPpackets?(Choosetwo)

A.TheyacknowledgereceiptofTCPsegments.

B.Theyguaranteedatagramdelivery.

C.Theycanprovidehostswithinformationaboutnetworkproblems.

D.TheyareencapsulatedwithinIPdatagrams.

E.TheyareencapsulatedwithinUDPdatagrams.

F.TheyareencapsulatedwithinTCPdatagrams.

正確答案：CD

C,D解析：Explanation:

pingmaybeusedtofindoutwhetherthelocalmachinesareconnectedtothe

networkorwhetheraremotesiteisreachable.Thistoolisacommonnetwork

toolfordeterminingthenetworkconnectivitywhichusesICMPprotocolinstead

ofTCP/IPandUDP/IP.Thisprotocolisusuallyassociatedwiththenetwork

managementtoolswhichprovidenetworkinformationtonetworkadministrators,

suchaspingandtraceroute(thelateralsousestheUDP/IPprotocol).

ICMPisquitedifferentfromtheTCP/IPandUDP/IPprotocols.Nosourceand

destinationportsareincludedinitspackets.Therefore,usualpacket-filtering

rulesforTCP/IPandUDP/IParenotapplicable.Fortunately,aspecial"si