How to configure totally open DMZ with OpenWRT?

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http://serverfault.com – I have OpenWRT router. I have NAS in my LAN, which i need to access from WAN and from all computers in the LAN. So, it should be accessible from any computer and it needs to access some of them, too. I read OpenWRT wiki and forums, and they recommend VLAN for network separation, but i do not need that - i want it all be on one network, so it can be visible to each other, and NAS visible from the WAN? Any idea, how that can be done? In case, if its important my equipment: Router Model: Buffalo WZR-HP-G300NH Firmware Version: OpenWrt Backfire 10.03.1 / LuCI 0.10.0 Release (0.10.0) (HowTos)