Let’s say we have two routers running EIGRP, these routers are connected via their S0/1 interfaces running HDLC.
What if you get a task that says configure a loopback 0 on R1 with an IP address of 1.1.1.1/24, R1 should advertise this route such that R2 sees the route as in EIGRP as an external route, R1 MUST redistribute static to accomplish this task, DO NOT configure a static route on R1 to accomplish this task.

ANS: we could issue the ‘ip default-network 1.1.1.0‘ command and then issue the ‘redistribute static’ command. When you issue the “IP Default-network” command you have to specify a classful network, meaning a major network, however, if you specify a subnetted network like 1.1.1.0/24 it will auto-inject a static route, and you can actually see it by doing a Show run, now all you need to do is redistribute static.

once we executed the ip default-network 1.1.1.0 on R1 and see the routing table of R1 then we could see that 1.1.1.1 is learn statically.