User's Manual

Configuring EIGRP
EIGRP Configuration Examples
IPC-274
Cisco IOS IP Configuration Guide
instead, this traffic will be sent to the null 0 interface where it is dropped.
The recommended way to send only the default route out a given interface is to use a
distribute-list command. You can configure this command to filter all outbound route
advertisements sent out the interface with the exception of the default (0.0.0.0).