Disabling DHCP Client Default Route
2011, May 07
If you do not wish for your router to install the default route it receives when DHCP client is enabled on an interface, use the command ip dhcp client default-router distance 255 to raise the administrative distance so it’s not entered into RIB. This is useful if you are using dynamic routing on a WAN interface, and want to use object tracking to detect lack of default routing.
!
interface FastEthernet0/0
description WAN LINK
bandwidth 1000000
ip dhcp client default-router distance 255
ip address dhcp