The ip address dhcp command can be used on FastEthernet and VLAN interfaces.
You cannot configure both ip address dhcp and keepalive-track (object tracking) on the WAN FastEthernet interface. You cannot configure both ip address dhcp and keepalive-icmp (extended keepalive) on the WAN FastEthernet interface. You cannot configure both ip address dhcp and ip address negotiated (PPP/IPCP address negotiation) on the WAN FastEthernet interface.
You can run ip address dhcp as many times as desired to re-initiate DHCP address negotiation. Whenever you change the value of a DHCP client parameter (such as client-id, client hostname), run ip address dhcp again to re-initiate DHCP address negotiation using the new values.
