1. CONFIGURE INTERFACE
interface ethernet 0
ip address 192.168.251.201 255.255.255.0
ip ospf authentication-key adcdefgh
!
router ospf 201
network 10.0.0.0 0.255.255.255 area 10.0.0.0
network 192.168.0.0 0.0.255.255 area 0
area 10.0.0.0 authentication
area 0 authentication
