well, I am using a cisco PIX with 6 interface and without NAT.
First you have to decide upon security level of your interfaces. The Highest the security level, the more protected.
nameif ethernet0 inside security100
nameif ethernet0 outside security10
nameif ethernet0 outside security20
....
nameif ethernet0 outside security30
if two interfaces have the same security level, they can not communicate.
There are two ways to avoid NAT:
1) use nat 0 with access-list any to any
nat 0 access-list ALL
access-list ALL permit ip any any
(or a moree specific access-list like fron inside ip's to dmz1, outside etc)...
2) use static commands
static (inside,outside) 192.168.190.0 192.168.190.0 netmask 255.255.255.0 0 0
static (inside,dmz1) 192.168.190.0 192.168.190.0 netmask 255.255.255.0 0 0
static (inside,dmz1) 192.168.190.0 192.168.190.0 netmask 255.255.255.0 0 0
static (dmz1,outside) 192.168.170.0 192.168.170.0 netmask 255.255.255.0 0 0
need to do static for all interfaces from high security priority to low security priority that you need access to or from...
