During my CCIE R&S preparation for lab exam, I encounter a task that requested me to advertise a subnet into OSPF routing protocol, but without using network statement or redistribution command. Since back then I was a little confuse about this, I said to post here maybe it help others.

Please download the topology used in this example here. We have already OSPF prepared and the task request to advertise interface Loopack0 from R0 to OSPF without using network statement or redistribution command.

See how to do it here:

Cisco-IGP cisco, loopback, ospf, tricky advertise