I came across a posting from Jim Wang, 
http://m0n0.ch/wall/list/showmsg.php?id=166/78, regarding testing the dhcp 
server on m0n0wall. He was looking to setup a dhcp subnet that is different 
to subnet the m0n0wall is in and have it serve IPs via a dhcp relay. I am 
also looking for this functionality.

Am not sure if I have explained this well, so here's an attempt in ascii.

Wireless Clients   ---->     Tropos      ----> m0n0wall
using DHCP               192.168.50.x/24       192.168.x.x/24
                          Relay DHCP to         DHCP subnet is
                          192.168.x.x           192.168.51.x/24

192.168.x.x is the m0n0wall IP.
192.168.50.x is the Tropos IP.

The idea is to have the clients use a different subnet to the tropos 
subnet. Tropos will be relaying to the m0n0wall so might or might not need 
a default route. Note that Tropos fills the giaddr field in the DHCP 
request with its own 192.168.50.x address.

Is this a supported configuration using m0n0wall?
---
Paul Daniels
Technical Director
Evolution Systems Ltd
Tel: 01270 588228  Fax: 01270580129