Existing setup - Multi-site MPLS network running BGP with Internet links setup as DMVPN running EIGRP for backup.
We are bringing up some smaller sites using only EIGRP and need to advertise the default gateway from the hub. It appears the summary address is what I need ? Any help is greatly appreciated .
This is because you have static default route which is preferred due to smaller administrative distance and installed in the routing table.
If you need that a default route from the Hub via the DMVPN tunnel then you must remove the other default route and as a replacement enter the specific route for the Hub tunnel source (physical address) so that tunnel can be created. As of know the tunnel endpoints are using the default route but since you need the default route via the tunnel itself you must enter specific routes to each tunnel endpoints.