【单选题】
Which feature prevents loops by moving a nontrunking port into an errdisable state when a BPDU is received on that port?___
A. BPDU filte
B. DHCP snooping
C. BPDU guard
D. Port Fast
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答案
D
解析
暂无解析
相关试题
【单选题】
Which command enables port security to use sticky MAC addresses on a switch?___
A. switchport port-security violation restrict
B. switchport port-security mac-address sticky
C. switchport port-security violation protect
D. switchport port-security
【单选题】
When you edit an IPS subsignature, what is the effect on the parent signature and the family of subsignatures?___
A. The change applies to the parent signature and the entire family of subsignatures
B. The change applies to the parent signature and the subsignature that you edit
C. The change applies only to subsignatures that are numbered sequentially after the subsignature that you edit
D. Other signatures are unaffected, the change applies only to the subsignature that you dit
【单选题】
Which type of mechanism does Cisco FirePOWER de ploy to protect ag detected moving across other networks?___
A. antivirus scanning
B. policy-based
C. reputation-based
D. signature-based
【单选题】
What action must you take on the ise to blacklist a wired device?___
A. Locate the switch through which the device is connected and push an a cl restricting all access by the device
B. Issue a CoA request for the de vice's mac address to each access switch in the network
C. Revoke the device's certificate so it is unable to authenticate to the network
D. Add the device's MAc address to a list of black listed devices
【单选题】
Which type of firewall can perform deep packet inspection?___
A. packet-filtering firewall
B. stateless firewall
C. application firewall
D. personal firewall
【单选题】
What is the main purpose of Control Plane Policing?___
A. to prevent exhaustion of route-proce ssor resources
B. to organize the egress packet queues
C. to define traffic classes
D. to maintain the policy map
【单选题】
Which attack can be prevented by OSPF authentication?___
A. smurf attack
B. IP spoofing attack
C. denial of service attack
D. buffer overflow attack
【单选题】
What is the best definition of hairpinning?___
A. ingress traffic that traverses the outbound interface on a device
B. traffic that enters one interface on a device and that exits through another interface
C. traffic that enters and exits a device through the same interface
D. traffic that tunnels through a device interface
【单选题】
Which SNMPv3 security level provides authentication using HMAC with MD5, but does not use encryption?___
A. authPriv
B. authNo Priv
C. noAuthNoPriv
D. NoauthPriv
【单选题】
You have implemented a dynamic blacklist, using security intelligence to block illicit network activity. However, the blacklist contains several approved connections that users must access for usiness pur poses. Which action can you take to retain the blacklist while allowing users to access the approve d sites?___
A. Create a whitelist and manually add the approved addresses.
B. Disable the dynamic blacklist and deny the specif ic address on a whitelist while permitting the others
C. Edit the dynamic blacklist to remove the approved addresses
D. Disable the dynamic blacklist and create a static blacklist in its place
【单选题】
When connecting to an external resource,you must change a source IP address to use one IP address from a range of 207.165.201.1 to 207.165.1.30. Which option do you implement ?___
A. dynamic source NAT that uses an IP ad dress as a mapped source
B. static destination NAT that uses a subnet as a real de stination
C. dynamic source NAT that uses a range as a mapped source
D. static destination NAT that uses a subnet as a real source
【单选题】
Refer to the exhibit. 【nat(ins,any)dynamic interface】Which ty pe of NaT is configured on a Cisco ASA?___
A. dynamic NAT
B. source identity NAT
C. dynamic PAT
D. identity twice NAT
【单选题】
Which mitigation technology for web-based threats prevents the removal of confidential data from the network?___
A. CTA
B. DCA
C. AMP
D. DLP
【单选题】
Refer to the exhibit. What is the effect of the given configuration?___
A. It establishes the preshared key for the switch
B. It establishes the preshared key for the firewall.
C. It establishes the preshared key for the Cisco ISE appliance
D. It establishes the preshared key for the router.
【多选题】
What are two major considerations when choosing between a SPAN and a TAP when plementing IPS?___
A. the type of analysis the iS will perform
B. the amount of bandwidth available
C. whether RX and TX signals will use separate ports
D. the way in which media errors will be handled
E. the way in which dropped packets will be handled
【多选题】
What are two direct-to-tower methods for redirecting web traffic to Cisco Cloud Web Security?___
A. third-party proxies
B. Cisco Catalyst platforms
C. Cisco NAC Agent
D. hosted PAC files
E. CiSco ISE
【多选题】
Which three descriptions of RADIUS are true? ___
A. It uses TCP as its transport protocol.
B. Only the password is encrypted
C. It supports multiple transport protocols
D. It uses UDP as its transport protocol
E. It combines authentication and authorization
F. It separates authentication,authorization,and accounting
【多选题】
Which two configurations can prevent VLAN hopping attack from attackers at VLAN 10?___
A. using switchport trunk native vlan 10 command on trunk ports
B. enabling BPDU guard on all access ports
C. creating VLAN 99 and using switchport trunk native vlan 99 command on trunk ports
D. applying ACl between VLAN
E. using switchport mode access command on all host ports
F. using switchport nonegotiate command on dynamic desirable ports
【多选题】
What are two features of transparent firewall mode ___
A. It conceals the presence of the firewall from attackers
B. It allows some traffic that is blocked in routed mode
C. It enables the aSA to perform as a router.
D. It acts as a routed hop in the network.
E. It is configured by default
【多选题】
Which two models of A sa tend to be used in a data center?___
A. 5555X
B. 5585X
C. ASA service module
D. 5512X
E. 5540
F. 5520
【多选题】
Which two statements about hardware-based encrption are true?___
A. It is widely accessible
B. It is potentially easier to compromise than software-based encryption. It requires minimal configuration
C. It requires minimal configuration
D. It can be implemented without impacting performance
E. It is highly cost-effective
【多选题】
In which two modes can the Cisco We b Security appliance be de ployed?___
A. as a transparent proxy using the Secure Sockets Layer protocol
B. as a transparent proxy using the Web Cache Communication Protocol
C. explicit proxy mode
D. as a transparent proxy using the Hyper Text Transfer Protocol
E. explicit active mode
【单选题】
1.三相刀开关的图形符号与交流接触器的主触点符号是___。
A. 一样的
B. 可以互换
C. 有区别的
D. 没有区别
【单选题】
2.刀开关的文字符号是___。
A. QS
B. SQ
C. SA
D. KM
【单选题】
3.行程开关的文字符号是___。
A. QS
B. SQ
C. SA
D. KM
【单选题】
4.交流接触器的文字符号是___。
A. QS
B. SQ
C. SA
D. KM
【单选题】
5.熔断器的作用是___。
A. 短路保护
B. 过载保护
C. 失压保护
D. 零压保护
【单选题】
6.热继电器的作用是___。
A. 短路保护
B. 过载保护
C. 失压保护
D. 零压保护
【单选题】
7.交流接触器的作用是可以___接通和断开负载。
A. 频繁地
B. 偶尔
C. 手动
D. 不需
【单选题】
8.三相异步电动机的启停控制线路由电源开关、熔断器、___、热继电器、按钮等组成。
A. 时间继电器
B. 速度继电器
C. 交流接触器
D. 漏电保护器
【单选题】
9.三相异步电动机的启停控制线路中需要有___、过载保护和失压保护功能。
A. 短路保护
B. 超速保护
C. 失磁保护
D. 零速保护
【单选题】
10维修电工以___、安装接线图和平面布置图最为重要。
A. 电气原理图
B. 电气设备图
C. 电气安装图
D. 电气组装图
【单选题】
11.熔断器的额定电压应___线路的工作电压。
A. 远大于
B. 不等于
C. 小于等于
D. 大于等于
【单选题】
12.对于电阻性负载,熔断器熔体的额定电流___线路的工作电流。
A. 远大于
B. 不等于
C. 等于或略大于
D. 等于或略小于
【单选题】
13.对于电动机负载,熔断器熔体的额定电流应选电动机额定电流的___倍。
A. 1~1.5
B. 1.5-2.5
C. 2.0~3.0
D. 2.5~3.5
【单选题】
14.使用快速熔断器时,一般按___来选择。
A. IN=1.03IF
B. IN=1.57IF
C. IN=2.57IF
D. IN=3IF
【单选题】
15.断路器中过电流脱扣器的额定电流应该大于等于线路的___。
A. 最大允许电流
B. 最大过载电流
C. 最大负载电流
D. 最大短路电流
【单选题】
16.短路电流很大的电气线路中宜选用___断路器。
A. 塑壳式
B. 限流型
C. 框架式
D. 直流快速
【单选题】
17.一般电气控制系统中宜选用___断路器。
A. 塑壳式
B. 限流型
C. 框架式
D. 直流快速
【单选题】
18.交流接触器一般用于控制___的负载。
A. 弱电
B. 无线电
C. 直流电
D. 交流电
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【判断题】
(70704)用指针式万用表测二极管反向电阻时,插在万用表标有“+”号插孔中的红表棒应接二极管的正极。( )(1.0分)
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【判断题】
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(70706)用万用表不同电阻挡测量二极管的正向电阻,读数都一样。( )(1.0分)
A. 对
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【判断题】
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A. 对
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【判断题】
(70708)通常硅二极管的正向压降比锗管的大,反向饱和电流比锗管的小。( )(1.0分)
A. 对
B. 错
【判断题】
(70709)ST3PA-A型时间继电器,其工作线圈的好坏可以用万用表电阻挡,从电源引脚进行测量。( )(1.0分)
A. 对
B. 错
【判断题】
(70710)二极管只要加正向电压就一定导通。( )(1.0分)
A. 对
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【判断题】
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A. 对
B. 错
【判断题】
(70712)三极管的电流放大作用,其实质是用一个较小的电流去控制一个较大的电流。( )(1.0分)
A. 对
B. 错
【判断题】
(70713)KLD-40PU型空调机组,机组包括全封闭压缩机2台,离心风机1台,蒸发器1台,冷凝器2台,电加热器1台,压力控制器4个,低温保护继电器1个,气液分离器2台,各自组成两个制冷系统。( )(1.0分)
A. 对
B. 错
【判断题】
(70714)三极管的输出特性曲线可分三个区,即饱和区、截止区和放大区。( )(1.0分)
A. 对
B. 错
【判断题】
(70715)当空调机组压缩机启动后,制冷剂流过起截流作用的毛细管时,会引起毛细管的颤动,如果毛细管没有颤动则说明没有制冷剂流过这根毛细管。( )(1.0分)
A. 对
B. 错
【判断题】
(70716)三极管的发射结正偏时,它必处于放大状态。( )(1.0分)
A. 对
B. 错
【判断题】
(70717)放大电路中所使用的三极管 值越大越好。( )(1.0分)
A. 对
B. 错
【判断题】
(70718)KLD-29PU型空调机组的P48J20ZY-G航空插头中使用了20根相同直径的导线。( )(1.0分)
A. 对
B. 错
【判断题】
(70719)三极管的一个电极作为公共端后,其他两个电极可分别作为输入端和输出端。( )(1.0分)
A. 对
B. 错
【判断题】
(70720)高低压力控制器的两个气室,分别与压缩机的排气管路和吸气管路相通。( )(1.0分)
A. 对
B. 错
【判断题】
(70721)空调器的蒸发温度越低,吹出的风越冷,房间降温就越快,制冷量就越大。( )(1.0分)
A. 对
B. 错
【判断题】
(70722)三极管具有电流放大作用,所以也具有能量放大作用。( )(1.0分)
A. 对
B. 错
【判断题】
(70723)温控器的设定温差过小会导致压缩机频繁启动和停机。( )(1.0分)
A. 对
B. 错
【判断题】
(70724)空调客车空调控制柜中转换继电器是用来均衡压缩机工作时间的。( )(1.0分)
A. 对
B. 错
【判断题】
(70725)用万用表R×1 k 挡测三极管,黑表棒接基极,红表棒分别和另外两个电极相接,如果测得的电阻都较小,则为PNP型管。( )(1.0分)
A. 对
B. 错
【判断题】
(70726)空调机制冷系统进行真空检漏时,可以用系统本身的压缩机来抽真空。( )(1.0分)
A. 对
B. 错
【判断题】
(70727)在使用二极管前通常不用检查极性,只检查它的好坏就行。( )(1.0分)
A. 对
B. 错
【判断题】
(70728)BSP青藏客车车体钢结构分为七大模块。( )(1.0分)
A. 对
B. 错
【判断题】
(70729)硅材料二极管的死区电压为0.3 V。( )(1.0分)
A. 对
B. 错
【判断题】
(70730)BSP青藏客车侧墙骨架与外皮板之间采用电阻焊。( )(1.0分)
A. 对
B. 错
【判断题】
(70731)根据二极管的单向导电性就可以判断它的好坏和极性。( )(1.0分)
A. 对
B. 错
【判断题】
(70732)BSP青藏客车车底密封舱底板为不锈钢板加筋板形式。( )(1.0分)
A. 对
B. 错
【判断题】
(70733)在测量二极管时,如果测得的正向电阻(常为几欧至几十欧)和反向电阻(常为几十千欧至几兆欧)相差倍数越大,说明管子的性能越好。( )(1.0分)
A. 对
B. 错