Cisco – Cisco IOS command for finding out the serial number of a switch / router

It sounds like what you're trying to do should be fine. You can have either the switch or the router provide the DHCP service. You'll want to enable dhcp snooping on the uplink port (setting it to untrusted). That SHOULD drop any DHCPOFFER coming in from there.

ip dhcp snooping

ip dhcp snooping vlan number 110 (or whatever)

for each interface (not the uplink):

interface fe0/0

ip dhcp snooping trust

then you should basically be good.

The router does not think it has an interface with that name run show ip int brief to get a list of interfaces present in the router

This may be of help.

Interface and Line Numbers in Cisco 1800, 2800 and 3800 Series Routers

www.cisco.com/en/US/products/hw/routers/ps282/products_tech_note09186a008035b051.shtml