Here is the output from the show ip dhcp binding command on a 3745:
Bindings from all pools not associated with VRF: IP address Client-ID/ Lease expiration Type Hardware address/ User name
172.16.0.20 0100.06b1.0bd5.7e Dec 21 2006 10:14 AM Automatic 172.16.0.21 0100.0d56.e11a.99 Dec 20 2006 03:22 PM AutomaticI cannot ping either the .20 or the .21 address. A MAC address is 48 bits so what kind of identifier is 0100.06b1.0bd5.7e (56 bits)?