These are commonly asked CCNA EIGRP exam questions. You might come across these but in a different contest, so it is beneficial if you understand the topic well.
Read a bit on EIGRP here
As usual, take time to read through the question so as to clearly understand what you are required to do.
Note: This EIGRP LAB are used for demonstration only, you will see different IP addressing, configuration and Port allocation in the real CCNA exam. But it all works the same way, try and understand the technique.
I suggest you use packet tracer for practice.
Download Cisco Packet tracer here
Refer to the exhibit below. After adding R3 router on the network, no routing updates are being exchanged between R3 and the new location. All other interconnectivity and Internet access for the existing locations of the company are working properly.
The task is to identify the fault(s) and correct the router configuration to provide full connectivity between the routers.
Access to the router CLI can be gained by clicking on the appropriate host. All passwords on all routers are Cisco.
IP addresses are listed in the chart below.
Answer and Explanation:
Its advised that you should read the question properly so as to understand what you are asked to do. Firstly, in this case; verify the configuration of the newly added router since it does not function properly.
Use the show running-config command from the command line interface of R3 router, (it’s also recommended to use this command on other routers on the network)
From the output above, we can verify that the Eigrp autonomous number (AS) of 22 configurations on router 3 is wrong.
On other routers, it is 212. If the AS numbers on routers in a network are mismatched, this will hinder the routers on that network from forming an adjacency.
To resolve this problem, you re-configure router R3 using the following command:
R3>enable (remember to enter cisco as the password here)
R3(config)#no router eigrp 22 (this will erase the initial configuration)
R3(config)#router eigrp 212
R3#copy running-config startup-config (remember to use this command after every configuration)
Verify the configuration on R1 router with the show running-config command:
You will notice that R3 network is missing in the configuration. R3 network address needs to be added for it to be linkable. Use the following command:
R1>enable (remember to enter cisco as password here)
R1(config)#router eigrp 212
R1#copy running-config startup-config
After configuration, use the ping command from R3 to verify connectivity.