[選擇題] 300-115 題庫答案修正 (持續更新)

xdong.woo

谢谢楼主的跟新，但是，其中还有个别题目，我觉得您这里也有问题：
: Y) ]8 v4 f+ Q5 f$ Z' p1 u) M; kQUESTION 261
; z0 [. U2 W5 r) t% OIf all devices on an EtherChannel are sending traffic to a single MAC address, which two methods of load balancing on the EtherChannel are preferred? (Choose two.)
! Y3 W& q4 B! G3 z8 ^- |  MA. destination-MAC
B. src-dst-MAC
" ^" o/ y+ l* H4 T% Q( \9 D5 UC. destination-IP
D. source-MAC
E. source-IP
! a' o& @" r. ]( a6 a! x, j  G2 zCorrect Answer: BD
5 w$ c0 |& d; E( t3 I9 M  y
题库的答案是B和E，其实我觉得B、D、E都正确！因为在同一个LAN中，IP和MAC地址肯定各不相同，应该都是可以的。不知道理解得对不对？
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' r# Q' H) A, P5 j& U+ F% lQUESTION 325
Which two statements about CDP are true? (Choose two.)
+ A9 Y9 ~$ ?2 P( bA. It can be disabled only at the interface level.
" r1 M+ u' H' r% {) |B. Devices with Cisco Discovery Protocol configured send advertisement messages to a multicast address on a periodic basis
# G. V' a) O" b) H  pC. It is disabled when switches have mismatched native VLANs.
  f) X% E; L) `! O/ ND. Devices with Cisco Discovery Protocol configured send advertisement messages to a broadcast address on a periodic basis.
: m* m- I" |. k) c5 iE. VTP relies on Cisco Discovery Protocol to carry VTP domain information
Correct Answer: BE
; Q, D0 p1 N7 X4 C. d: w
$ x* a! ]3 I* t9 m* j/ I题库的答案是BC。主要争议点是C或者E。我查了下网上（抱歉，没有太多时间查思科资料了），CDP2开始，是可以支持native vlan及domain-name的，但是，E答案中，我理解的意思是VTP是依靠CDP携带VTP域信息的，诚然CDP是可以携带一些信息，但是，VTP自己的报文，也是携带这些信息的，我的理解是，CDP只是起到辅助的功能，并不能说是依赖。相比较，C答案中，disabled应该是理解为不可用。当trunk中的native vlan不匹配的时候，CDP能够运行，但是应该是不可用的，相比较下，C答案可能会更好些。
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xdong.woo

QUESTION 449
3 `) A- z2 z* VWhich statement is true about SPAN on a switch?
A. It would double the source traffic.
B. On every source port configured, there would be another port that can not be used normally.
C. Hence source traffic...........
D. http://bbs.hh010.com/
Correct Answer: B
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! q3 {) J8 @2 b楼主，好像这题也有问题，您选的是B，意思是，在SPAN中，每当一个源端口配置时，将有另外一个端口不能正常使用。其实，题目想表达的意思就是，一个源端口对应一个目的端口，但是，多个源端口是可以对已一个目的端口的，所以，我认为A选项更加好些。因为，当数据到到源端口的出站队列时，会被复制一份发给目的端口。源端口数据应该是翻倍了，至少在交换机内部是这样吧？

kkg

xdong.woo 发表于 2018-7-12 17:46
QUESTION 449
Which statement is true about SPAN on a switch?
A. It would double the source traffic ...

' H& X/ ~  Q! \: m) F, ]您好。
9 E) p1 B3 Y1 c( s1 x& a" ~
这道题我也想了一阵子，想说说我的想法。
' e/ K$ [* R6 u: _- T' W' B
- P" q5 ~6 \& E3 B在某些特殊情况下A可能也不能说是一定就对。
- e; s* l8 ^/ d4 q9 k* Z! p4 R比如只复制源端口数据流中的一部分的情况，就不能绝对就是说是将源端口数据流（作为一个整体）加倍了。
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不知道您觉得有道理吗？

asas5656

xdong.woo 发表于 2018-7-12 17:40
( w6 o2 Z% b$ H+ l谢谢楼主的跟新，但是，其中还有个别题目，我觉得您这里也有问题：
QUESTION 261
5 Z3 Y: t) [8 P: `If all devices on an E ...

4 m5 o8 H' A; t+ yQUESTION 261
. q6 K5 V& K; B8 T' Mpreferred 我認為是選最佳的，BDE皆可以沒錯，但BD只要再L2 header check就可load balancing , E 須到 L3header check才能load balancing.
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) A# P3 F5 q" \/ Y5 O5 |' NQUESTION 325
- w7 E% s4 e) _8 P這題我認同你的說法，BC看來還是最佳解。

asas5656

xdong.woo 发表于 2018-7-12 17:46
QUESTION 449
4 Q' {1 c( j7 k: j/ YWhich statement is true about SPAN on a switch?
A. It would double the source traffic ...

3 F3 E  T6 x* w$ j+ s* G7 v% WQUESTION 449
  {( p0 w4 ~1 e7 ?/ s  eA選項，同33樓敘述說明。
: t6 J6 X: e& j3 ^  I9 ?% h/ C, E" XB選項，我的想法是不管有幾個 source port 被設定，至少要有一個 destination port 。destination port 不能正常使用Layer 2 portocol (STP, VTP, CDP, DTP, PagP) another port可以是同一個port 也可以是不同的port。

hym21

asas5656 发表于 2018-6-20 23:17
; u% v6 j5 _4 k) V% g感謝說明
Q152, Q231 lab 是將其中switch access port指派vlan，再把vlan移除嗎? 想請教如何驗證？

Q152 Q231  
/ ^3 ^: B: Y9 ^- w8 k  L7 I6 B6 O這兩題就簡單的lab 測試就可以得知了
. p1 u9 a2 I1 @% p9 x把port指派vlan , 再把vlan移除  show vlan
再把vlan 加回去 再show vlan 一次
5 ?/ Y! }3 P! A  q應該就會看到答案了

hchen01

QUESTION 483   -- 考点是frame， level 2， 所以是 switch protection, 选A （另一相似的题是packet，level 3, block unicast）
9 A; f) D, M0 [& PWhichcommand can be used to block a frame with an unknown destination MAC addressfrom being forwarded out of an interface?
A.switchport protected
B.It is not forwarded if the destination MAC address is unknown
C.switchport port-fast
D.switchport block unicast
1 H( a9 ^! X) n( JCorrect Answer: D


3 u5 R4 ~8 D$ R$ [QUESTION484  -- 考点是 within a VLAN, 不是在router上，C 更合适
  a8 W# L& A1 t6 m- h& V* FForwhich reason does an administrator disable MAC address learning within a VLAN?
A.to configure a VLAN as an SVI
5 Z6 {) x3 ], h1 RB.to free up space in the MAC address table
C.to implement port security
D.to reduce flooding in the network
CorrectAnswer: B

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  j2 O, V. ], Q" ~  aQUESTION485  -- 我觉得考点是manually-configured， 所以不能启用协商， A 是对的。
Whichtwo statements about manually-configured LACP EtherChannels are true? (Choosetwo.)
2 n6 f4 _# G& w! xA.LACP negotiation must be disabled on both devices in the EtherChannel
( j* U) ]$ n1 iB.They require Cisco Discovery Protocol.
  Z/ A2 P: V+ o" \. i; mC.Each physical port in the EtherChannel must have the same speed and duplexsettings.
D.LACP negotiation must be disabled on one device in the EtherChannel.
) S% a. J3 N( u2 m, @, zE.They use an MD5 hash for equal load balancing.
/ ]2 U7 ?0 w" }% f" KF.If the physical port configurations on the two devices are different, the portsare placed into the
% P9 q5 D5 c. M/ P! X; a5 A7 [; F/ Derrdisabledstate
CorrectAnswer: CF

( e7 A" W5 j. m7 T  W1 pQUESTION 498   B 和 C 都有不对的地方， B更合适， C 说 log traffic on a VLAN, 再加上multiple switches， 语病跟多。
Forwhich reason would you configure RSPAN instead of SPAN on your network?
A.RSPAN provides more complete monitoring of the traffic on a single switch.
B.Only RSPAN devices can monitor traffic on other device
9 J+ y' ?4 N2 c! }C.Only RSPAN can log traffic on a VLAN that spans multiple switches.
D.Only RSPAN supports STP on multiple switches across a campus.
Correct Answer: C

QUESTION 504   这题答案B没有任何问题， 就跟配了switch access vlan 593 一样， 实际测试
D 选项在打switchport host 之前 是否需要先打 switchport 命令？
Whichconfiguration do you apply to an interface so that a host can be placed intoVLAN 593?
A.interface GigabitEthernet0/0.593
encapsulationdot1q 593
+ d6 n) Q1 Y& {0 A: R& Iswitchportaccess vlan 593
  ?+ d; f2 ^2 UB.interface GigabitEthernet0/0
  L" y) a5 V$ y* \3 z1 w, Cswitchporttrunk encapsulation dot1q
switchporttrunk native vlan 593
switchportaccess vlan 593
C.interface GigabitEthernet0/0
/ C; a: p- l6 A6 F4 sswitchportmode trunk
- }* U8 d! I  k' i1 O5 s4 fswitchporttrunk allowed vlan 593
9 A6 D! u5 _  `& q5 E# s" lD.interface GigabitEthernet0/0
switchportmode access
$ F6 b6 ~, r) L: T; ?5 _switchportaccess vlan 593
& w5 b8 B. j' y4 W6 gswitchport host
Correct Answer: D
Section: part11
% Z9 R- E) k: f8 V# x, q2 kExplanation
$ |/ `4 O, H# H+ ?$ X% vExplanation/Reference:

hchen01

补充4题
3 p/ @: E- i0 _7 x  h5 {QUESTION 590
Which two packet types are used by the TACACS+ authentication process? (Choose two.)
A. request
' t0 R( x3 i4 W# u7 SB. reply
C. start
D. response
E. continue
7 \% ~7 X7 ]7 B  E5 HCorrect Answer: BE

8 \. ]9 q  Y0 r) M  H4 @参考：https://tools.ietf.org/id/draft-ietf-opsawg-tacacs-07.html 是不是应该选B, C 和 E
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3 S0 }' t& N/ \6 MAuthentication
The Authentication START Packet Body
The Authentication REPLY Packet Body
The Authentication CONTINUE Packet Body
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QUESTION 592
5 {, T, E* [4 `7 n4 p. h. HWhich two packet types are used by the TACACS+ accounting process? (Choose two.)
A. start
B. request
6 C9 _. ]: S2 m4 VC. continue
D. response
E. reply
  u' M7 \! g( P$ ?Correct Answer: BD
: @" T, @4 h6 Z3 m- h
参考 https://tools.ietf.org/id/draft-ietf-opsawg-tacacs-07.html， 是不是应该选B, E
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. g' t( x9 a% p3 O9 ?7 JAccounting
The Account REQUEST Packet Body
The Accounting REPLY Packet Body

, \) v& ^5 L, iQUESTION 614
1 N* z* q( W0 q1 L7 {# LWhich two commands display the VLANs that are present in the VLAN database? (Choose two.)
A. show running-config
B. show vlan database
+ A) \+ C+ y2 o* \C. show vlan brief
( v6 }7 t: o" v- _D. show vlan
3 ^- D0 R6 X4 c' a& s0 J  r5 LE. show vlan id
/ [$ C) h; N! v7 i& \4 m& QCorrect Answer: AD


# ^: {. L* K2 V+ T我觉得应该选C 和 D， 因为show running-config 只能包含 vtp transparent模式下的VLAN信息， 其他模式是不包含在running-config里的。
: v& P; C, E" q1 x另外show vlan brief是可以显示所有VLAN信息的， 只是没有详细信息。
4 p1 o* L9 m8 }' ?% ^/ M, M) g
QUESTION 594
# X! J; z+ k1 |; ^+ a" tWhat is the command to enable BPDU filter on an access port?
A. spanning-tree portfast bpdufilter default
" P  o* X1 x4 e1 KB. spanning-tree portfast bpduguard default
1 L4 u) j/ b- v, ?( j& ZC. spanning-tree bpdufilter enable
D. spanning-tree bpdufilter default
Correct Answer: A

1 W% I( ^  E7 N2 K( J! o: O, UAt the interface level, you can enable BPDU filtering on any interface by using the spanning-tree bpdufilter enable interface configuration command w ithout also enabling the Port Fast feature. This command prevents the interface from sending or receiving BPDUs.
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* |  N- K  ^7 [答案是不是应该选 C？

asus_css

hchen01 发表于 2018-8-7 18:55
QUESTION 483   -- 考点是frame， level 2， 所以是 switch protection, 选A （另一相似的题是packet，leve ...

解释的很清楚 谢谢

asus_css

hchen01 发表于 2018-8-7 18:55
* U' ?( W( [  J; j5 ~- ^1 I. p; `QUESTION 483   -- 考点是frame， level 2， 所以是 switch protection, 选A （另一相似的题是packet，leve ...

) r; L3 {7 B1 S7 ?+ C# K解释的很清楚 谢谢

u96628

感謝分享!

Inconsolable

QUESTION 504  实测，BD 两种都可以把HOST放进593

kumheezucisco

Q480 我感觉也应该是C 到底哪个正确啊
0 ?5 S3 V  k! \) j$ i) ?" a% V
--> The (MAC) address table lists the destination MAC address, the associated VLAN ID, and port number associated with the address and the type (static or dynamic).
https://www.cisco.com/c/en/us/td ... _Guide/mac_lrn.html

' b" B) Y$ i( L( S5 IQ412 个人感觉有三个正确答案 ABE

ych5470

這太重要了，感謝。

kenfang888

QUESTION 152
3 e, |" Z8 M) r' R) h3 `4 U
Interfaces are assigned to aVLAN, and then the VLAN is deleted. Which state are these interfaces in after theVLAN is deleted?
9 y/ u. F3 B6 |) d! @
8 B- a6 J* e4 D' ^3 pA.They remain up, but they are reassigned to the default VLAN

B.They go down until they are reassigned to a VLAN.

' Q9 U( G) V, G! t1 \4 vC.They go down, but they are reassigned to the default VLAN.
& E) g/ U6 r3 U1 S& @+ Q& ^; H6 g9 _
; ]) Y% L$ i: k$ SD.They remain up, but they are reassigned to the native VLAN.
1 P7 q5 N8 }, X9 [$ ~6 Z2 B
Correct Answer: A
! E6 [. T: B8 ]1 _* F0 n4 g! `2 r經過實驗應該是B，雖然查看介面顯示是UP的，但是實際是down的，封包過不去，一直到Vlan重新分配。
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