Prerequisites: CCNP level skills.
Personal Note
Found this little contraption at:
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ftoadsup.html
Topology
Task 1
Configure IP addresses and OSPF according to the topology diagram (pic. 1). Advertise loopback interfaces in the appropriate areas as stub networks.
Task 2
Create a loopback1 interface on R3 with IP address 192.168.3.3/24.
Task 3
Configure area 13 as NSSA. Redistribute R3's loopback1 interface into OSPF.
Task 2
Create a loopback1 interface on R3 with IP address 192.168.3.3/24.
Task 3
Configure area 13 as NSSA. Redistribute R3's loopback1 interface into OSPF.
Task 4
Verify if R1 receives the E2 prefix 192.168.3.0/24.
Task 5
On ABR filter out 172.16.103.3/32. R2 should not receive 192.168.3.0/24 anymore. The reason: the forwarding address (172.16.103.3) is no longer reachable.
Task 6
Change the forwarding address for 192.168.3.0/24 so R1 becomes the gateway (forwarding address = 0.0.0.0).
Lab Solution
R1 OSPF Configuration:
R2 OSPF Configuration:
R3 OSPF Configuration:
Task 2
R3 Configuration:
Task 3
R1 Configuration:
R3 Configuration:
Verification:
Note!
Note!
I removed OSPF from R3 and re-created it, but this time R3 does NOT advertise 172.16.103.3/32.
On ABR filter out 172.16.103.3/32. R2 should not receive 192.168.3.0/24 anymore. The reason: the forwarding address (172.16.103.3) is no longer reachable.
Task 6
Change the forwarding address for 192.168.3.0/24 so R1 becomes the gateway (forwarding address = 0.0.0.0).
Lab Solution
Task 1
Configure IP addresses and OSPF according to the topology diagram (pic. 1). Advertise loopback interfaces in the appropriate areas as stub networks.
R1 OSPF Configuration:
!
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
network 10.1.12.1 0.0.0.0 area 0
network 10.1.13.1 0.0.0.0 area 13
network 172.16.101.1 0.0.0.0 area 0
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
network 10.1.12.1 0.0.0.0 area 0
network 10.1.13.1 0.0.0.0 area 13
network 172.16.101.1 0.0.0.0 area 0
!
R2 OSPF Configuration:
!
router ospf 1
router-id 2.2.2.2
log-adjacency-changes
network 10.1.12.2 0.0.0.0 area 0
network 172.16.102.2 0.0.0.0 area 0
router-id 2.2.2.2
log-adjacency-changes
network 10.1.12.2 0.0.0.0 area 0
network 172.16.102.2 0.0.0.0 area 0
!
R3 OSPF Configuration:
!
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
network 10.1.13.3 0.0.0.0 area 13
network 172.16.103.3 0.0.0.0 area 13
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
network 10.1.13.3 0.0.0.0 area 13
network 172.16.103.3 0.0.0.0 area 13
!
Task 2
Create a loopback1 interface on R3 with IP address 192.168.3.3/24.
R3 Configuration:
!
interface Loopback1
ip address 192.168.3.3 255.255.255.0
ip address 192.168.3.3 255.255.255.0
!
Task 3
Configure area 13 as NSSA. Redistribute R3's loopback1 interface into OSPF.
R1 Configuration:
!
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
area 13 nssa
network 10.1.12.1 0.0.0.0 area 0
network 10.1.13.1 0.0.0.0 area 13
network 172.16.101.1 0.0.0.0 area 0
router-id 1.1.1.1
log-adjacency-changes
area 13 nssa
network 10.1.12.1 0.0.0.0 area 0
network 10.1.13.1 0.0.0.0 area 13
network 172.16.101.1 0.0.0.0 area 0
!
R3 Configuration:
!
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
area 13 nssa
redistribute connected subnets
network 10.1.13.3 0.0.0.0 area 13
network 172.16.103.3 0.0.0.0 area 13
!
router-id 3.3.3.3
log-adjacency-changes
area 13 nssa
redistribute connected subnets
network 10.1.13.3 0.0.0.0 area 13
network 172.16.103.3 0.0.0.0 area 13
!
Verification:
Pic. 2 - R3's OSPF Database (NSSA).
Pic. 3 - R1's OSPF Database (NSSA).
Pic. 4 - R1 OSPF Database (External).
On all routers R3's loopback becomes the forwarding address to 192.168.3.0/24.
Note!
I removed OSPF from R3 and re-created it, but this time R3 does NOT advertise 172.16.103.3/32.
R3 New OSPF Configuration:
!
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
area 13 nssa
redistribute connected subnets
network 10.1.13.3 0.0.0.0 area 13
!
router-id 3.3.3.3
log-adjacency-changes
area 13 nssa
redistribute connected subnets
network 10.1.13.3 0.0.0.0 area 13
!
Note!
Without loopback0 (172.16.103.3) being advertised on R3, all routers use 10.1.13.3 as the forwarding address. It must be reachable in order to get to 192.168.3.0/24.
(I have brought back the original configuration on R3 (with loopback0 being advertised.)
Task 4
Verify if R1 receives the E2 prefix 192.168.3.0/24.
Pic. 5 - R2 Receives 192.168.3.0/24 (forwarding address 172.16.103.3)
On ABR filter out 172.16.103.3/32. R2 should not receive 192.168.3.0/24 anymore. The reason: the forwarding address (172.16.103.3) is no longer reachable.
R1 Configuration:
!
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
area 13 nssa
area 13 range 172.16.103.0 255.255.255.0 not-advertise
network 10.1.12.1 0.0.0.0 area 0
network 10.1.13.1 0.0.0.0 area 13
network 172.16.101.1 0.0.0.0 area 0
router-id 1.1.1.1
log-adjacency-changes
area 13 nssa
area 13 range 172.16.103.0 255.255.255.0 not-advertise
network 10.1.12.1 0.0.0.0 area 0
network 10.1.13.1 0.0.0.0 area 13
network 172.16.101.1 0.0.0.0 area 0
!
Verification:
Pic. 6 - R2 Routing Table Missing.
The forwarding address 172.16.103.3 has been filtered out and is inaccessible. As a result of that, 192.168.3.0/24 cannot be used in the routing table.
Pic. 7 - R2 OSPF Database External.
Change the forwarding address for 192.168.3.0/24 so R1 becomes the gateway (forwarding address = 0.0.0.0).
R1 Configuration:
!
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
area 13 nssa translate type7 suppress-fa
area 13 range 172.16.103.0 255.255.255.0 not-advertise
network 10.1.12.1 0.0.0.0 area 0
network 10.1.13.1 0.0.0.0 area 13
network 172.16.101.1 0.0.0.0 area 0
router-id 1.1.1.1
log-adjacency-changes
area 13 nssa translate type7 suppress-fa
area 13 range 172.16.103.0 255.255.255.0 not-advertise
network 10.1.12.1 0.0.0.0 area 0
network 10.1.13.1 0.0.0.0 area 13
network 172.16.101.1 0.0.0.0 area 0
!
Verification:
Pic. 8 - R2 Routing Table.
Pic. 9 - R2's OSPF Database (External).
