CCNA EIGRP Exam Lab AS Configuration

CCNA EIGRP Exam Lab AS Configuration 

Question

CCNA EIGRP AS Configuration Exam Lab: Your office has added a new router Router3 to current network. But there is some configuration issue between Router3 and the network, because currently no router is receiving the routing-updates from Router3. All other connectivity like ISP Internet is working fine.

Your task is to recognize the faults in configuration and correct them in a way you get full connectivity between the all networks. All routers have the default password cisco. IP configurations of all devices are as under:

RouteRouter1
S0/0: 192.168.36.13

S1/0: 198.0.18.6
S0/1: 192.168.60.25

Fa0/0: 192.168.77.33

Router2
S0/0: 192.168.36.14

Fa0/0: 192.168.60.97
Fa0/1: 192.168.60.113

Router3
Fa0/1: 192.168.60.65
Fa1/0: 192.168.60.81

Fa0/0: 192.168.77.34

Router4
S0/1: 192.168.60.26

Fa0/0: 192.168.60.129
Fa0/1: 192.168.60.145

Solution and explanation

For troubleshooting the lab you need to check out the configuration on newly added router that is router3. Run the command show RUN on router3. From the output of router3, we find that it is wrongly configured with an autonomous number of 22. If the AS numbers among the connected routers are different then no adjacency will be formed. You also need to make sure that you have the same AS on the entire router in the network.

To correct the configurations, you simply need to re-configure router3 with the correct AS following configurations:

ROUTER3#configure terminal

ROUTER3(config)#no router eigrp 22

ROUTER3(config)#router eigrp 212

ROUTER3(config-router)#network 192.168.60.0

ROUTER3(config-router)#network 192.168.77.0

ROUTER3(config-router)#no auto-summary

ROUTER3(config-router)#end

ROUTER3#copy running-config startup-config

Check configuration on Router1:

You will notice that there is missing network of Router3. Therefore we have to advertise here so that it can accessible on Router3

ROUTER1>enable 

ROUTER1#configure terminal

ROUTER1(config)#router eigrp 212

ROUTER1(config-router)#network 192.168.77.0

ROUTER1(config-router)#end

ROUTER1#copy running-config startup-config

Verification:

After the above configuration you will have the full connectivity. You should check again with ping command from router3 to other routers!

Some new updates in EIRGP lab:

In the above simulation’s configuration if you find the passive-interface configuration in ROUTER1 configuration. If the link between ROUTER1 to Router2 or ROUTER1 to Router3 have the passive interface then we need to remove it. You can use the no passive-interface command because it prevents EIGRP routing updates from being sent on these interfaces. But if the “passive interface” is applied to the link between ROUTER1 and ISP-router in following way:

ROUTER1:

!

.
router eigrp 212
passive-interface s1/0
.

.

Then we don’t need to change anything on ROUTER1 because the link between ROUTER1 & ISP doesn’t need EIGRP to run on it.

There is a static router command ip default-network command in ROUTER1, this is correct so that all the routers can access the Internet.

That all, thank you for reading. Share your comments and CCNA exam experience. Visit some other practice labs for CCNA.