OSPF Routing Protocol¶
OSPF (Open Shortest Path First) is a routing protocol used to allow internetwork communication between two or more routers.
OSPFv2¶
OSPFv2 is the IPv4 version of the OSPF routing protocol and is configured as followed.
Single Area OSPF¶
router(config)# router ospf 1
router(config-router)# network [network-id] [wildcard mask] area [ospf-area-number]
Remember to add all adjacent networks using the network [network-id] [wildcard mask] area [ospf-area-number] command.
Static and Default Routes¶
If there are default or static routes that need to be advertised use this command:
## For default routes
router(config-router)# default-information originate
## For static Routes
router(config-router)# redistribute static
or
router(config-router)# redistribute static subnets
First, log onto the router and enter global configuration mode
OSPF Authentication¶
OSPF can be configured to authenticate every OSPF message. This is usually done to prevent a rogue router from injecting false routing information and therefore causing a Denial-of-Service attack.
- Two types of authentication can be used:
clear text authentication – clear text passwords are used
MD5 authentication – MD5 authentication is used. This type of authentication is more secure because the password doesn’t go in clear-text over the network.
R1(config)# router ospf 1
R1(config-router)# area 0 authentication message-digest
R1(config-router)# exit
R1(config)# int [interface]
R1(config-if)# ip ospf message-digest-key 1 md5 [password]
R2(config)# router ospf 1
R2(config-router)# area 0 authentication message-digest
R2(config-router)# exit
R2(config)# int [interface]
R2(config-if)# ip ospf message-digest-key 1 md5 [password]