Let’s get an IPv4 default route into EIGRP. There are a few methods to do it. I hate most of them, though. I think it will be obvious which one I like.
Here’s the lab I have set up to test everything. I want R4 to generate the default in each case.
Default Network - Candidate default. I don’t think I’ve ever used that all my years in networking, but here’s how to use it in EIGRP for a default route. You basically say “If you don’t know where to send a packet, send it to where network X lives.” We’re going to set the 192.168.1.0/24 as the default network, so, in our case X = 192.168.1.0. R4 will tag that route as a default candidate when it advertises it to the rest of the network. The config is easy but requires a classful (yes, classful) network to be configured as the default.