Routing packets from one WAN to the other WAN
We are using an ER605 to provide a guest network with its own IP range and DHCP server. This network is accessible via the LAN ports. The WAN port is connected to our main network (10.0.0.0/22), which has its own Internet access via a different router. The WAN/LAN1 port uses pppoe to connect to a fiber modem.
WAN: Our main network (10.0.0.0/22) with multplie systems including another Internet router.
WAN/LAN1: pppoe using a fiber modem.
LAN: 192.168.0.0./24 guest network with DHCP.
The guest LAN works fine and it uses the fiber connection for its Internet, unless this is down and then the LAN successfully uses the Internet of the main network.
We would like the main network (on the WAN port) to be able to use the fiber Internet (on the WAN/LAN1 port) as well, mainly as a backup option to provide Internet access for the main network. To do this the ER605 needs to route the packets from the WAN port to the WAN/LAN1 port. Is this possible? And if so, how do I make this happen?