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Configuring Stub Area

area area-id stub 

area area-id default-cost cost router configuration command on the ABR to change the cost of the

default route. The default cost is 1.

Default route is automatically advertised.

Configuring Totally Stubby Areas

area area-id stub router configuration command

area area-id stub no-summary at the ABR router.

area area-id default-cost cost  command to change the cost.

Configuring NSSAs

summary-address address if needed to redistribute something. 

area area-id nssa [no-redistribution] [default-information-originate] [metric metric-value] [metric-

type type-value] [no-summary] router configuration command. The no-summary keyword is used only

on the ABR for totally stubby NSSA areas, not just NSSAs.

no-redistribution - When the router is an NSSA ABR and it imports routes only into the standard areas.

but not into the NSSA area.

metric type - type 1 or type 2

Configuring Totally Stubby NSSAs

summary-address address if needed to redistribute something. 

area area-id nssa [no-redistribution] [default-information-originate] [metric metric-value] [metric-

type type-value] [no-summary] router configuration command. The no-summary keyword is used only

on the ABR. The ABR automatically generates O*N2 default routes, sp there is no need to use the

default-information-originate parameter.

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The ABR for stub and totally stubby areas generates a summary LSA with the link-

state ID 0.0.0.0, so there is no need to use the default-information-originate

command.

The ABR for NSSA does not generate a default route by default. To make itgenerate the default route, use the default-information-originate parameter in

the area area-id nssa command.

The ABR for totally stubby NSSAs automatically generates a default route.

Verify Area Types

show ip ospf - OSPF information: which areas are standard, stub ot NSSA

show ip ospf database - details of LSAs

show ip ospf database nssa-external - specific details of each LSA type 7 update in the database

show ip route

Configure Simple Password Authentication

ip ospf authentication-key password interface configuration command to assign a key.

To hide the password using encryption type 7, use the service password-authentication command.

ip ospf authentication [message-digest | null] interface configuration command. To use simple

password authentication, use the command without any parameters.

If authentication is required on an area, not an interface, use:

area area-id authentication [message-digest] router configuration command.

To verify simple password, use:

show ip ospf interface to see if simple password is enabled

show ip ospf neighbor to see if an adjacency is formed

To configure simple password for a virtual link, use:

area area-id authentication router configuration command to use authentication for the whoe area

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area area-id virtual-link router-id (of the end-side router) authentication-key key command.

Configure OSPF MD5 Authentication

ip ospf message-digest-key key-id md5 key interface configuration command. The key ID can range

from 1 to 255.

ip ospf authentication message-digest interface configuration command.