i am testing routing protocol redistribute,now i have a question.R1,R2 and R3 is direct connection of eachother. eigrp running on R2 and R3 . R1 has a loopback interface.R2 need a loopback route,so i use ip route command. when i use ip route ip_address 0.0.0.0 next_hop_address and network at eigrp session in R2,i can not show up in R3. when i change form,i use ip route ip_address 0.0.0.0 interface_name.then R3's route table has this route.