I need some help configuring this scenario.  I have four public addresses
from my ISP.  These four addresses are part of a class C network that is
shared by others -- bridged.  Let's say my addresses are 1.2.3.101 to
1.2.3.104 with a gateway address of 1.2.3.1 and a netmask of 255.255.255.0
(/24).  I have a m0n0wall router attached to a DSL Modem with WAN address
configured to 1.2.3.101.  This m0n0wall presents a LAN network of
10.0.0.0/24.
 
I would like to configure a second m0n0wall router behind the first one. The
physical connection to the second m0n0wall is the LAN of the first m0n0wall
- 10.0.0.0/24.  The WAN interface of this second m0n0wall needs to be one of
the public ip addresses in my address range - let's say 1.2.3.102.
 
Is this kind of think possible?  I've tried several configurations with no
luck and need a push in the right direction.  Should I be using Static
Routing, NAT 1:1, Server NAT or something else.
 

Thanks in advance!!  Greg