DHCP On-Demand

R1: interface Serial 0/1
encapsulation ppp
ip address negotiated
ppp ipcp mask request
ppp ipcp dns request
no peer neighbor-route
!
!
ip dhcp pool ODAP_POOL
import all
origin ipcp
!
router rip no validate-update-source
____

R3:
interface Serial 1/2
encapsulation ppp
ip address 155.1.13.3 255.255.255.0
peer default ip address 155.1.13.1
ppp ipcp mask 255.255.255.0
ppp ipcp dns 155.1.146.4 155.1.146.6
no peer neighbor-route