У меня примерно так на PPPoE серваке:
hostname gw3.serv.linet
password 99999
enable password 99999
!
interface lagg0
ip ospf message-digest-key 10 md5 88888
ip ospf priority 255
!
router ospf
ospf router-id 10.1.10.3
default-information originate
redistribute connected
network 10.1.10.0/24 area 0.0.0.0
area 0.0.0.0 authentication message-digest
!
log file /var/log/ospfd.log
!
line vty