Cisco CCNA mock exam questions sample test – Question 98

.Which command was used to create the following configuration?

A. Router(config-router)# network 192.168.1.0 0.0.0.15
B. Router(config-router)# network 192.168.1.0 255.255.255.0
C. Router(config-router)# network 192.168.1.80
Router(config-router)# network 192.168.1.128
D. Router(config-router)# network 192.168.1.0

Correct Answer: D

Explanation:
The network 192.168.1.0 command instructs the router to activate EIGRP on every interface that belongs to the class C network 192.168.1.0. The exhibit indicates that the router is
running EIGRP on two subnets of 192.168.1.0 (192.168.1.80/28 and 192.168.1.128/28). Since both of these are subnets of the same class C network number, only the class C
address needs to be referenced with a network statement.
All interfaces that will participate in EIGRP must be specified with a network command that specifying the network of which the interface is a member. Failure to do so will result in
neighbor relationships not forming. In the example below, Router A and Router B are directly connected, but not forming a neighbor relationship. The network they share is the
192.168.5.0/24 network. The output of the show run command for both routers reveals that Router B does not have EIGRP running on the 192.168.5.0 network.
The network 192.168.1.0 0.0.0.15 command is incorrect because only the class C network number (192.168.1.0) needs to be referenced to enable EIGRP on all subnets. It is actually
valid to include an inverse mask with EIGRP network statements, but it is unnecessary in this case, and the network/mask provided does not match either of the routed networks.
The network 192.168.1.0 255.255.255.0 command is incorrect because the mask is unnecessary in this case, and if masks are included, they must be expressed inversely
(0.0.0.255).
It is unnecessary to configure two network commands in this example, as both networks are subnets of the same class C network (192.168.1.0), and a single network command can
enable EIGRP on both. Additionally, if specific subnets are referenced in network commands, it is necessary to include an inverse mask after them, or EIGRP will automatically
summarize the command to the classful boundary.
Objective:
Routing Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot EIGRP for IPv4 (excluding authentication, filtering, manual summarization, redistribution, stub)
References:
Cisco > Cisco IOS IP Routing Protocols Configuration Guide, Release 12.4T > Part 3: EIGRP > Configuring EIGR