Help with DHCP Forwarding

Hi all. I'm not sure I'm posting this in the correct forum. Let me know if I should move it.

I'm trying to setup a downstream router. I have a fairly standard gateway box that provides NAT, DCHP, etc. I want to add another router for QOS.

I'd like to go from the gateway to the QOS box, then out to the LAN/WAN. I assume I need to go into the WAN side of the QOS box to get QOS. I'd also like DHCP to pass through the QOS box and provide DHCP for the LAN-side clients - everything on 10.0.1.0/24.

I can't get through from the LAN side of the QOS box to the gateway. I guessing I need to add some filters (iptables) to the QOS box.

Any suggestions?

We need to know more about your QOS box.

Sure. Thanks for replying.

The QOS box is an ASUS N66 running TomatoUSB. The gateway is an ASUS N66 running Merlin, soon to become an ASUS AC68. I don't know if it matters, but I'm also going to put a Netgear GS105E switch between the two boxes to take advantage of the mirroring port.

I'm open to any configuration, as long as the gateway continues to run Merlin.

---------- Post updated at 10:01 PM ---------- Previous update was at 05:36 PM ----------

I have a feeling that I'm making a newbie mistake here. This seems like something lots of people would need to do. Is it a mistake to even try to do this?