BASIC OSPF CONFIGURATION

BASIC OSPF CONFIGURATION

SUMMARY STEPS
configure terminal
router ospf process-id !Enables OSPF routing and enters router configuration mode.
network ip-address wildcard-mask area area-id !Defines an interface on which OSPF runs and defines the area ID for that interface.
end

1. ENABLING OSPF:

R1:
conf t
router ospf 1
network 10.10.12.0 0.0.0.255 area 0
network 10.10.13.0 0.0.0.255 area 0
end
wr
!
R2:
conf t
router ospf 1
network 10.10.12.0 0.0.0.255 area 0
network 10.10.23.0 0.0.0.255 area 0
end
wr
!
R3:
conf t
router ospf 1
network 10.10.13.0 0.0.0.255 area 0
network 10.10.23.0 0.0.0.255 area 0
end
wr

2. CHANGING THE RID:
NOTE: Verify RID using show ip protocols.
R2:
conf t
interface loopback 0
ip address 2.2.2.2 255.255.255.0 !This did not work. Had to change RID using router-id 2.2.2.2.
end
wr
!
R3:
conf t
router ospf 1
router-id 3.3.3.3
Reload or use "clear ip ospf process" command, for this to take effect
end
wr

3. CHANGING THE COST:
NOTE: To verify OSPF cost on an interface, use show ip ospf interface gi0/2.
!
R2:
conf t
interface gi0/2
ip ospf cost 50
end
wr

4. ADVERTISE A DEFAULT ROUTE INTO OSPF:
NOTE: If you don’t already have a default route in your routing table, you need to add the always keyword.

R2:
conf t
router ospf 1
default-information originate always
end
wr


5. CONFIGURE PLAINTEXT AUTHENTICATION B/W R2 AND R3:

R2:
conf t
interface gi0/2
ip ospf authentication
ip ospf authentication-key cisco
end
wr

R3:
conf t
interface gi0/2
ip ospf authentication
ip ospf authentication-key cisco
end
wr

6. CONFIFGURE MD5 AUTHENTICATION B/W R1 AND R3:
R1:
conf t
interface gi0/1
ip ospf authentication message-digest
ip ospf message-digest-key 1 md5 cisco
!
R3:
conf t
interface gi0/1
ip ospf authentication message-digest
ip ospf message-digest-key 1 md5 cisco
end
wr

7. CONFIGURE MD5 AUTHENTICATION IN AN AREA:
R3:
conf t
router ospf 1
area 0 authentication
area 0 authentication message-digest
end
wr

8. CHANGE THE OSPF TIMERS B/W R2 AND R3:
NOTE: To verify OSPF timers, use show ip ospf interface g0/2.
R2:
conf t
interface gi0/2
ip ospf hello-interval 5
ip ospf dead-interval 20
end
wr
!
R3:
conf t
interface gi0/2
ip ospf hello-interval 5
ip ospf dead-interval 20
end
wr

VERIFY:
show ip ospf neighbor
show ip protocols
show ip route ospf
clear ip ospf process
show ip ospf interface fa1/0
debug ip ospf packet

REFERENCES:
IP Routing: OSPF Configuration Guide

Configure and Troubleshoot OSPF | Cisco CCNA 200-301:

OSPF Design Guide

OSPF: Frequently Asked Questions

What Are OSPF Areas and Virtual Links?

OSPF Database Explanation Guide

#cisco #ccna #ccnp #ccie

[FerdsTechChannel]

I hope you found this video helpful, please like, subscribe and click the notification bell so you won't miss future videos. Thanks for your support! ❤
If you have any comments and questions, please use the comment section below.