Hello, I am currently running a cascaded router setup in the following way:
Router (AVM Fritzbox) --- FW (OpenWRT) -- Net1 | |- Net2 DirtyDMZ
The router has a static route to Net1/2, and NAT in the FW is disabled.
The router delegates IPv6 prefixes to the FW.
The DirtyDMZ is necessary because I only get a /62 net from my provider, so I do not have more than 2 nets behind the FW.
This works fine so far.
Now, I want to introduce a DNS recursor into the DMZ. For IPv4, this works fine, I just set DHCP option 6 with the local 10.x.x.x IP of the recursor.
Now IPv6 is a problem. Since I do not have a static IPv6 prefix, I enabled ULA addresses in the router, which works fine for the recursor. However the WAN6 interface of the FW does NOT get any ULA address, which obviously breaks routing from Net1/2 into the DMZ via ULA addresses.
How do I get WLAN6 to accept a ULA address from the router?
(Note that I do not want to use DNS forwarding via OpenWRT, because in the next step, I want client based DNS resolving, so the request from the clients have to reach the recursor directly.)