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CCNA® Cisco Certified Network Associate: Study Guide, Seventh Edition by Todd Lammle

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Troubleshooting OSPF

This section will have you verify sample OSPF configurations and configuration outputs in order to troubleshoot, maintain, and fix OSPF-related issues.

If you see a configuration as shown here, you must know that there is no way a router will accept this input because the wildcard is incorrect:

Router(config)#router ospf 1

Router(config-router)#network 10.0.0.0 255.0.0.0 area 0

This would be the correct statement:

Router(config)#router ospf 1

Router(config-router)#network 10.0.0.0 0.255.255.255 area 0

Next, let’s take a look at a figure and see if we can determine which of the routers will become the designated router of the area. Figure 9-7 shows a network with six routers connected by two switches and a WAN link.

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