Cisco Certified Network Associate (CCNA)

Exam 200-301Cisco Certified Network Associate (CCNA 2021) Demo Questions

200-301: Cisco Certified Network Associate 2021 (Apr 2021)

QUESTION 1

How does the dynamically-learned MAC address feature function?

A. Switches dynamically learn MAC addresses of each connecting CAM table

B. It requires a minimum number of secure MAC addresses to be filled dynamically

C. The CAM table is empty until ingress traffic arrives at each port

D. The ports are restricted and learn up to a maximum of 10 dynamically-learned addresses

Answer: C

當電腦傳送 Frame 至另一電腦時，Switch 便會在過程中學習該介面的 MAC address 並記錄至 CAM

table (Content Addressable Memory) 內。

QUESTION 2

Which goal is achieved by the implementation of private IPv4 addressing on a network?

A. allows servers and workstations to communicate across public network boundaries

B. provides a reduction in size of the forwarding table on network routers

C. allows communication across the Internet to other private networks

D. provides an added level of protection against Internet exposure

Answer: D

因為 private IP address 不能直接連上 Internet，變相被 Internet 外來入侵的機會相對減少。

QUESTION 3

What is the same for both copper and fiber interfaces when using SFP modules?

A. They offer reliable bandwidth up to 100 Mbps in half duplex mode

B. They support an inline optical attenuator to enhance signal strength

C. They provide minimal interruption to services by being hot-swappable

D. The accommodate single-mode and multi-mode in a single module

Answer: C

QUESTION 4

Refer to the exhibit. An engineer must add a subnet for a new office that will add 20 users to the network.

Which IPv4 network and subnet mask combination does the engineer assign to minimize wasting addresses?

A. 10.10.225.48 255.255.255.240

B. 10.10.225.32 255.255.255.240

C. 10.10.225.48 255.255.255.224

D. 10.10.225.32 255.255.255.224

Answer: D

答案 A 和 B 不正確，因為當 subnet mask 係 255.255.255.240 的時侯，可用的 IP address 只有 14 個，

不能滿足題目的需求 20 個 IP address。餘下的兩個答案 C 和 D，當 subnet mask 係 255.255.255.224

的時侯，只有 10.10.225.32 的網絡是其中一個的 subnet。

QUESTION 5

An office has 8 floors with approximately 30-40 users per floor. Only one subnet should be used. Which

command must be configured on the router Switched Virtual Interface to use address space efficiently?

A. ip address 192.168.0.0 255.255.0.0

B. ip address 192.168.0.0 255.255.254.0

C. ip address 192.168.0.0 255.255.255.128

D. ip address 192.168.0.0 255.255.255.224

Answer: B

這題說明 8 層樓每層 多 40 個 users，合共 多 320 個 IP address，而題目要求只需要 1 個 subnet，所要

要用 255.255.255.254 作為 subnet mask 組成一個擁用 多 512 個 IP address 的 subnet 便可滿足要求。

QUESTION 6

Which command prevents passwords from being stored in the configuration as plaintext on a router or switch?

A. enable secret

B. service password-encryption

C. username cisco password encrypt

D. enable password

Answer: B

使用 service password-encryption 便可為 running-config 內的純文字密碼加密 (encrypt)。

QUESTION 7

Refer to the exhibit. An administrator configures four switches for local authentication using passwords that are

stored as a cryptographic hash. The four switches must also support SSH access for administrators to manage

the network infrastructure. Which switch is configured correctly to meet these requirements?

A. SW1

B. SW2

C. SW3

D. SW4

Answer: C

QUESTION 8

Refer to the exhibit. How does router R1 handle traffic to 192.168.10.16?

A. It selects the EIGRP route because it has the lowest administrative distance

B. It selects the RIP route because it has the longest prefix inclusive of the destination address

C. It selects the OSFP route because it has the lowest cost

D. It selects the IS-IS route because it has the shortest prefix inclusive of the destination address

Answer: B

如果 Router 要處理前往 192.168.10.16 的 packet，以上 routing table 的四行 routing path 都可以去到，

但 router 首先會根據 longest prefix 的路徑作為 routing path，以上例子 “R 192.168.10.0/27…” 的 RIP

比其它長，所以 router 會用作首選的 routing path。

Reference: Route Selection in Cisco Routers

https://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/8651-21.html

QUESTION 9

Refer to the exhibit. Which route does R1 select for traffic that is destined to 192 168.16.2?

A. 192.168.16.0/21

B. 192.168.16.0/24

C. 192.168 16.0/26

D. 192.168.16.0/27

Answer: D

上面題目的 routing path 都是從不同的 Routing protocols 接收回來，但 prefix length 四個長度不同，分

別為 /21, /24, /26, /27，由於 /27 是 長的 prefix length，所以 Router 會選擇第四行作首選的路徑

“i L1 192.168.16.0/27…” 處理有關 packet。

Reference: Route Selection in Cisco Routers

https://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/8651-21.html

QUESTION 10

Refer to the exhibit. Router R1 is running three different routing protocols. Which route characteristic is used

by the router to forward the packet that it receives for destination IP 172.16.32.1?

A. administrative distance

B. longest prefix

C. metric

D. cost

Answer: B

上面題目的 routing path 都是從不同的 Routing protocols 接收回來，但 prefix length 三個長度不同，分

別為 /19, /24, /27，由於 /27 是 長的 prefix length，所以 Router 會選擇第一行 EIGRP 作首選的路徑

“ D 172.16.32.0/27 [90/2888597172] via 20.1.1.1 ” 處理有關 packet。

QUESTION 11

Refer to the exhibit. If configuring a static default route on the router with the ip route 0.0.0.0 0.0.0.0

10.13.0.1 120 command, how does the router respond?

A. It ignores the new static route until the existing OSPF default route is removed

B. It immediately replaces the existing OSPF route in the routing table with the newly configured static route

C. It starts load-balancing traffic between the two default routes

D. It starts sending traffic without a specific matching entry in the routing table to Gigabit Ethernet0/1

Answer: A

The above default route command has the Administrative Distance (AD) of 120, which is bigger than the AD of

OSPF External route (O*E2) so it will not be pushed into the routing table until the current OSPF External

route is removed.

For your information, if you don’t type the AD of 120 (using the command “ip route 0.0.0.0 0.0.0.0 10.13.0.1”)

then the new static default route would replace the OSPF default route as the default AD of static route is 1. You

will see such line in the routing table: S* 0.0.0.0/0 [1/0] via 10.13.0.1

QUESTION 12

Refer to the exhibit. Which command configures a floating static route to provide a backup to the primary link?

A. ip route 0.0.0.0 0.0.0.0 209.165.202.131

B. ip route 209.165.200.224 255.255.255.224 209.165.202.129 254

C. ip route 0.0.0.0 0.0.0.0 209.165.200.224

D. ip route 209.165.201.0 255.255.255.224 209.165.202.130

Answer: B

QUESTION 13

A router running EIGRP has learned the same route from two different paths. Which parameter does the router

use to select the best path?

A. cost

B. administrative distance

C. metric

D. as-path

Answer: C

如果 Router 發覺在 Routing table 內有 “同一種” Routing Protocol 擁有多個一條的 routing path 去

“同一個” 網絡，Router 會根據 Metric 選擇路徑。

QUESTION 14

Which two actions influence the EIGRP route selection process? (Choose two)

A. The router calculates the reported distance by multiplying the delay on the exiting Interface by 256.

B. The router calculates the best backup path to the destination route and assigns it as the feasible successor.

C. The router calculates the feasible distance of all paths to the destination route

D. The advertised distance is calculated by a downstream neighbor to inform the local router of the bandwidth

on the link

E. The router must use the advertised distance as the metric for any given route

Answer: B, C

Feasible successor is the backup route. To be a feasible successor, the route must have an Advertised distance

(AD) less than the Feasible distance (FD) of the current successor route -> Answer B is correct.

Feasible distance (FD): The sum of the AD plus the cost between the local router and the next-hop router. The

router must calculate the FD of all paths to choose the best path to put into the routing table.

QUESTION 15

Router A learns the same route from two different neighbors, one of the neighbor routers is an OSPF neighbor

and the other is an EIGRP neighbor. What is the administrative distance of the route that will be installed in the

routing table?

A. 20

B. 90

C. 110

D. 115

Answer: B

由於 EIGRP 的 AD 數值是 90，OSPF 的 AD 數值是 110，所以 Router 會選擇 EIGRP 的路徑。

QUESTION 16

Refer to the exhibit. Which prefix does Router 1 use to Host A?

A. 10.10.10.0/28

B. 10.10.13.0/25

C. 10.10.13.144/28

D. 10.10.13.208/29

Answer: D

Router1 如果要傳送 packet 至 Host A，會根據 routing table 內以下的 routing path：

O 10.10.13.208/29 [110/2] via 10.10.10.1, 00:00:04, GigabitEthernet0/0

這個網絡 的 IP address 範圍是 208 215，Host A：10.10.13.214 就在這範圍之內。

QUESTION 17

Refer to the exhibit. A packet is being sent across router R1 to host 172.16.3.14. To which destination does the

router send the packet?

A. 207.165.200.246 via Serial0/1/0

B. 207.165.200.254 via Serial0/0/0

C. 207.165 200.254 via Serial0/0/1

D. 207.165.200.250 via Serial0/0/0

Answer: C

如果前往 host 172.16.3.14，Router 基於 longest subnet perfix 便會選擇 OSPF 這條路徑處理，即是這一行

"O 172.16.3.0/28 [110/84437] via 207.165.200.254, 00:00:28, Serial0/0/1"

而這個網絡 172.16.3.0/28 subnet 包含的 IP address 範圍是 0 15。

QUESTION 18

Refer to the exhibit. A packet is being sent across router R1 to host 172.16.0.14. To which destination does the

router send the packet?

A. 209.165.200.246 via Serial0/1/0

B. 209.165.200.254 via Serial0/0/0

C. 209.165 200.254 via Serial0/0/1

D. 209.165.200.250 via Serial0/0/0

Answer: A

這題小心和上一題混淆，圖片和答案選擇都有點不同。這題問如果前往 host 172.16.0.14，由於在 routing

table 內沒有特定處理這個 network 的 routing path，所以 後會由 default route 處理，即是 S* 那一

行，所以 Router 會交給 209.165.200.246 via Serial0/1/0 處理相關 packet。

QUESTION 19

Refer to the exhibit. If OSPF is running on this network, how does Router2 handle traffic from Site B to

10.10.13.128/25 at Site A?

A. It is unreachable and discards the traffic

B. It load-balances traffic out of Fa0/1 and Fa0/2

C. It sends packets out of interface Fa0/1

D. It sends packets out of interface Fa0/2

Answer: A

由於以上的 Routing table 沒有處理前往目的地網絡 10.10.13.128/25 相關的 routing path，而且沒有

default route 處理前往 unknown 網絡的路由，到 後 Router 會將有關 packet 丟棄 (discard)。

QUESTION 20

Refer to the exhibit. The show ip ospf interface command has been executed on R1. How is OSPF

configured?

A. The interface is not participating in OSPF

B. There are six OSPF neighbors on this interface

C. The default Hello and Dead timers are in use

D. A point-to-point network type is configured

Answer: C

QUESTION 21

An engineer must configure an OSPF neighbor relationship between router R1 and R3. The authentication

configuration has been configured and the connecting interfaces are in the same 192.168 1.0/30 subnet. What

are the next two steps to complete the configuration? (Choose two.)

A. configure the hello and dead timers to match on both sides

B. configure the same process ID for the router OSPF process

C. configure the same router ID on both routing processes

D. configure the interfaces as OSPF active on both sides

E. configure both interfaces with the same area ID

Answer: A, E

設定 OSPF 時注意兩邊 router 的介面需要相同的 hello and dead timer，Area ID 也需要一樣。

QUESTION 22

Refer to the exhibit. With which metric was the route to host 172.16.0.202 learned?

A. 0

B. 110

C. 38443

D. 3184439

Answer: C

Reference/Explanation:

如果要傳送包封至目的地電腦 172.16.0.202，Routing table 只有 OSPF route 172.16.0.128/25 才符合。

因為 172.16.0.128/25 的情況下，這個網絡的 IP address range 是 128 256，而目的地電腦 “202” 正

正在這範圍內。所以 router 會以 OSPF route 處理，而這行 route 的 metric value 是 38443。

答案 D 的 EIGRP routing path 不符合這目的地電腦的範圍，因為 172.16.0.192/29，網絡的 IP address

range 是 192 199。

QUESTION 23

Refer to the exhibit. After the configuration is applied, the two routers fail to establish an OSPF neighbor

relationship. What is the reason for the problem?

A. The OSPF router IDs are mismatched.

B. Router2 is using the default hello timer.

C. The network statement on Router1 is misconfigured.

D. The OSPF process IDs are mismatched

Answer: B

Reference/Explanation:

OSPF 的預設 hello timer 是 10 秒，而這裡 Router1 使用 ip ospf hello-interval 5 指令修改

預設的 hello timer 至 5 秒，但 Router2 沒有修改，即沿用預設值 10 秒，所以導致雙方 router 的 hello

timer 不相同，不能建立鄰接關係 (adjacency) 交換 routing table。

QUESTION 24Drag and drop the application protocol from the left onto the transport protocols that it uses on the right.

Answer:

QUESTION 25

Refer to the exhibit. Drag and drop the networking parameters from the left onto the correct values on the right.

Select and Place:

Answer:

QUESTION 26

An engineer is configuring the router to provide static NAT for the web server. Drag and drop the configuration

commands from the left onto the letters that correspond to its position in the configuration on the right.

Answer:

QUESTION 27

Drag the descriptions of IP protocol transmissions from the left onto the IP traffic types on the right.

Select and Place:

Answer:

QUESTION 28

Drag the characteristics of network architectures from the left onto the type of architecture on the right

Answer:

QUESTION 29

Drag and drop the steps in a standard DNS lookup operation from the left onto the sequence on the right.

Answer: