This is the walkthrough for OSPF Lab #1.

Here’s the topology:

Click here for the initial configs

Here is task one:
1. Configure R1′s s0/0.102 interface and R2′s s0/0.201 interface in area 12, this area should not receive any Type 5 LSAs. Configure R1′s s0/0.103 interface and R3′s s0/0.301 interface in area 13, R1 should only receive a default route from R3, no other OSPF routes should be in R1′s RIB (from R3). Do not use network statements to accomplish this task.

Config:

R1(config)#interface Serial0/0.102 point-to-point
R1(config-subif)#ip ospf 100 area 12
R1(config-subif)#
R1(config-subif)#interface Serial0/0.103 point-to-point
R1(config-subif)#ip ospf 100 area 13
R1(config-subif)#
R1(config-subif)#router ospf 100
R1(config-router)#area 12 stub
R1(config-router)#area 13 stub
 
R2(config)#interface Serial0/0.201 point-to-point
R2(config-subif)#ip ospf 100 area 12
R2(config-subif)#
R2(config-subif)#router ospf 100
R2(config-router)#area 12 stub
 
R3(config)#interface Serial0/0.301 point-to-point
R3(config-subif)#ip ospf 100 area 13
R3(config-subif)#
R3(config-subif)#router ospf 100
R3(config-router)#area 13 stub no-summary

Here we configure OSPF 100 under the routers’ interfaces (avoiding network statements). Then we configure R1 and R2′s link/area as a stub. Last we configure R1 and R3′s link/area as a totally stubby area, preventing R3 from sending anything buy a default route to R1.