About OSPF

OSPF is a link-state dynamic routing protocol. Routers build an LSDB and use the SPF algorithm to select paths.

enable
configure terminal
router ospf 1
 router-id 1.1.1.1
 network 10.0.0.0 0.0.0.255 area 0
end
show ip ospf neighbor
show ip route ospf

A wildcard mask is the inverse of a subnet mask. OSPF neighbors must agree on parameters such as area, subnet, hello/dead timers and authentication.

Practice

Build an area 0 topology with three routers in Packet Tracer and verify neighbor states.