R4
enable
config t
router rip
version 2
no auto-summary
network 23.0.0.4
network 23.0.0.0
R5
enable
config t
router rip
version 2
no auto-summary
network 23.0.0.12
network 23.0.0.0
R6
enable
config t
router rip
version 2
no auto-summary
network 23.0.0.4
network 23.0.0.8
R7
enable
config t
router rip
version 2
no auto-summary
network 23.0.0.8
network 23.0.0.12