OSPF Notes - RigPig/NET-330 GitHub Wiki

Take the above network example in packet tracer. I have assigned IPs and inputted the necessary commands into the router CLIs for OSPF routing to work. I shall break down the commands and concepts should I need to look at them later.

  1. Enable OSPF routing process

router ospf 1

  • This command starts the OSPF configuration on a router. The number at the end is the process ID, it can be any number.
  1. Tell OSPF Which Networks to Advertise

network <network_address> <wildcard_mask> area <area_number>

For example:

network 10.18.1.20 0.0.0.3 area 0

This is defining what network you want OSPF to advertise and form neighboring relationships on - with the wildcard mask (inverse of subnet mask) - and the OSPF area ID. All routers in the same area form adjacencies. Area 0 is the backbone area and is required.

  1. Verification Commands

show ip ospf neighbor

This command shows adjacency of other router's IPs as neighboring links.

show ip route ospf

This command shows learned routes from OSPF.

show ip ospf interface brief

This command shows which interfaces are participating in OSPF.