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26.
A router has been configured with the commands router eigrp 9 and network
172.16.1.0 0.0.0.255 . No other EIGRP-related commands have been configured. The
answers list the IP addresses that could be assigned to this router’s Fa0/0 interface.
Which answers list an IP address/prefix length that would cause the router to enable
EIGRP on Fa0/0? (Choose two answers.)
- A.172.16.0.1/23
- B.172.16.1.1/26
- C.172.16.1.1/24
- D.172.16.0.255/23
- E.None of the other answers are correct
- Answer & Explanation
- Report
Answer : [B][C]
Explanation :
Explanation :
| The network 172.16.1.0 0.0.0.255 command tells Cisco IOS to match the first three octets when comparing the interface IP addresses to the configured “172.16.1.0” value. Only two answers match in the first three octets. The other two answers have a 0 in the third octet, making the addresses not match the network command. |
27.
Router R1 has working interfaces S0/0, S0/1, and S0/2, with IP address/prefix combinations
of 10.10.10.1/24, 10.10.11.2/24, and 10.10.12.3/22. R1’s configuration includes
the commands router eigrp 9 and network 10.0.0.0 . The show ip eigrp interfaces
command lists S0/0 and S0/1 in the command output, but not S0/2. Which answer
gives a possible reason for the omission?
- A.R1 has EIGRP neighbors reachable through S0/0 and S0/1, but not through S0/2, so it is not included.
- B.S0/2 might currently be in a state other than up/up.
- C.The network 10.0.0.0 command requires the use of mask 255.0.0.0 because of EIGRP being classful by default.
- D.S0/2 might be configured as a passive interface.
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| The show ip eigrp interfaces command displays interfaces on which EIGRP has been enabled but omits passive interfaces. Making the interface passive would omit the interface from the output of this command |
28.
Routers R1 and R2 are EIGRP neighbors using their Fa0/0 interfaces, respectively. An
engineer adds the ip hello-interval eigrp 9 6 command to R1’s Fa0/0 configuration.
Which of the following is true regarding the results from this change?
- A.The show ip eigrp neighbors command on R1 lists the revised Hello timer.
- B.The show ip eigrp interfaces command on R1 lists the revised Hello timer
- C.The R1-R2 neighborship fails because of a Hello timer mismatch.
- D.The show ip eigrp interfaces detail command on R1 lists the revised Hello timer.
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| The show ip eigrp interfaces detail command does display a router’s EIGRP Hello timer setting for each enabled interface. The other listed commands do not display the timer. Also, EIGRP routers do not have to have matching Hello timers to become neighbors. |
29.
Router R1 has been configured with the commands router eigrp 9 and network
172.16.2.0 0.0.0.255 , with no other current EIGRP configuration. R1’s (working)
Fa0/0 interface has been configured with IP address 172.16.2.2/26. R1 has found
three EIGRP neighbors reachable through interface Fa0/0, including the router
with IP address 172.16.2.20. When the engineer attempts to add the neighbor
172.16.2.20 fa0/0 command in EIGRP configuration mode, which of the following
occurs?
- A.Fa0/0 fails.
- B.The command is rejected.
- C.The existing three neighbors fail.
- D.The neighborship with 172.16.2.20 fails and then reestablishes
- E.None of the other answers is correct.
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| The neighbor 172.16.2.20 fa0/0 command would only be rejected if the IP address (172.16.2.20) is not inside the range of addresses in the subnet (172.16.2.0/26, range 172.16.2.0–172.16.2.63). This command does not impact the interface state. The command does disable all EIGRP multicasts, and because the three dynamically discovered neighbors require the EIGRP multicasts, all three neighbors fail. Although 172.16.2.20 is a valid potential neighbor, both routers must be configured with static neighbor commands, and we know that 172.16.2.20 was not previously configured with a static neighbor command; otherwise, it could not have been a neighbor with R1. |
30.
Which of the following settings could prevent two potential EIGRP neighbors from
becoming neighbors? (Choose two answers.)
- A.The interface used by one router to connect to the other router is passive in the EIGRP process.
- B.Duplicate EIGRP router IDs.
- C.Mismatched Hold Timers.
- D.IP addresses of 10.1.1.1/24 and 10.2.2.2/24, respectively
- Answer & Explanation
- Report
Answer : [A][D]
Explanation :
Explanation :
| For EIGRP, Router IDs do not have to be unique for EIGRP routers to become neighbors, and the hold timer does not have to match between the two neighbors. However, making an interface passive disables the processing of all EIGRP messages on the interface, preventing all neighborships. Mismatched IP subnets also prevent neighborships from forming. |
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