R1#sh run | b ospf
router ospf 1
 log-adjacency-changes
 network 17.57.100.1 0.0.0.0 area 0
!



R3#sh run | b ospf
router ospf 1
 log-adjacency-changes
 network 17.80.1.1 0.0.0.0 area 0
!



R4#sh run | b ospf
router ospf 1
 log-adjacency-changes
 network 17.80.1.2 0.0.0.0 area 0
!



S6#sh run | b ospf
router ospf 1
 log-adjacency-changes
 network 17.57.100.2 0.0.0.0 area 0
!