Configuring OSPF Static Neighbors

Step 1: Create the physical topology in GNS3 as show in the image below :

Step 2: Configure IPv4 address on the physical interface of the routers :

R1(config)#interface FastEthernet0/0
R1(config-if)#ip address 10.1.1.1 255.255.255.0
R1(config-if)#no shutdown
R1(config-if)#interface Serial1/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#no shutdown

R2(config)#interface FastEthernet0/0
R2(config-if)#ip address 10.1.1.2 255.255.255.0
R2(config-if)#no shutdown

R3(config-if)#interface Serial1/0
R3(config-if)#ip address 192.168.1.2 255.255.255.0
R3(config-if)#no shutdown

Step 3: Configuring OSPF process on all the routers with the command router ospf <process-id> :

R1(config)#router ospf 1
R1(config-router)#exit

R2(config)#router ospf 1
R2(config-router)#exit

R3(config)#router ospf 1
R3(config-router)#exit

Step 4: Enabling OSPF on the interfaces with the interface level sub-command ip ospf <process-id> area <area-id> :

R1(config)#interface FastEthernet0/0
R1(config-if)#ip ospf 1 area 0
R1(config-if)#interface Serial1/0
R1(config-if)#ip ospf 1 area 0

R2(config)#interface FastEthernet0/0
R2(config-if)#ip ospf 1 area 0

R3(config-if)#interface Serial1/0
R3(config-if)#ip ospf 1 area 0

Step 5: Checking the IPv4 routing table on the routers and seeing OSPF route entry :

R1#show ip route

R2#show ip route

R3#show ip route

Step 6: Checking OSPF neighbor relationships with the show command, show ip ospf neighbor :

R1#show ip ospf neighbor

R2#show ip ospf neighbor

R3#show ip ospf neighbor

Step 7: Configuring OSPF network type on serial interface of R1 and R3 :

R1(config)#interface serial1/0
R1(config-if)#ip ospf network non-broadcast

R3(config)#interface serial1/0
R3(config-if)#ip ospf network non-broadcast

Step 8: Checking OSPF neighbors relationships on R1 and R3 :

R1#show ip ospf neighbor

• OPSF neighbor relationship with R3 using neighbor-id 192.168.1.2 is removed.

R3#show ip ospf neighbor

• No OSPF neighbor relationship.

Step 9: Configuring OSPF static neighbor on R1 pointing to R3 and vice versa :

R1(config)#router ospf 1
R1(config-router)#neighbor 192.168.1.2

R3(config-if)#router ospf 1
R3(config-router)#neighbor 192.168.1.1

Step 10: Verify the OSPF neighbor relationships formed using the show ip ospf neighbor command :

R1#show ip ospf neighbor

• OPSF neighbor relationship with R2 and R3 using neighbor-id 10.1.1.2 & 192.168.1.2 respectively.

R2#show ip ospf neighbor

• OPSF neighbor relationship with R2 using neighbor-id 192.168.1.1.

R3#show ip ospf neighbor

• OPSF neighbor relationship with R1 using neighbor-id 192.168.1.1.

Step 11: Verifying connectivity throughout the topology :

Pre-requisites : Open shortest path first (OSPF) router roles and configuration, OSPF network types