Setting up load balancing with mwan3 on openwrt

I have met similar problem and I can share solution which appears to be very simple. In OpenWRT the feature you are looking at is plain port forward.

Open you router IP, typically http://192.168.1.1

In Network menu, choose Firewall, the Port Frowards. Scroll down to "New port forward" and add:

• Name: ALL->DMZ
• Protocol: choose do you need both TCP=UDP or just TCP
• External zone: wan
• External Port: leave empty!!!
• Internal zone: lan
• Internal IP address: choose IP of host, in your case it's NAS
• Internal port: leave empty!!!

Click Add, and Save & Apply.

That will work exactly the same as in other routers firmware "DMZ host", the host with ALL external traffic redirected to it by default.

To have more security I recommend you to forward only ports you need, without exposing it widely to Internet.

If you will want to add additional SINGLE Port Forwards, they will be added to the end of list. IMPORTANT: always move rule ALL->DMZ to the bottom of the list and "Save & Apply". The rules are processed in the order, so the first one met condition and others do not work.

Best Regards, Arunas B.

Don't bother with DNS forwarding, or with OpenWrt's internal DNS server, just serve the existing DNS servers to your DHCP clients directly. You can do this by setting DHCP option 6, which will be formatted in the web interface like:

6,192.168.32.35,192.168.48.35

You can access the relevant part of the web interface in LuCI by going through Network --> Interfaces --> LAN --> Scroll down to bottom --> "Advanced Settings" tab:

I also have to remind you to do this only with the explicit knowledge and approval of your company's network admin, IT department, etc.