I will confess to being an absolute Pi virgin so be kind.
I have a Draytek Vigor 130 configured in bridge mode, which then goes to an unmanaged switch, and on to a Google WiFi router. To access the Vigor 130 wegui (for linestats etc) I have a standalone laptop connected to the unmanaged switch configured IPv4 as 192.168.2.10, subnet 255.255.255.0, no gateway, no dns. This allows me to interrogate the Vigor 130 on it's IP of 192.168.2.1 directly. Obviously my 'internal network is separated from this shenanigans. It is not possible to configure the Google WiFi to allow any form of forwarding etc to access the Vigor 130 so I have to do it this way, which is fine enough.
Now, I saw a thread on the interwebs where someone had used a Pi3 in the same manner but had the Vigor 130 connected to eth0 and ALSO used it's WiFi to connect to their 'internal' LAN which facilitated using VNC to/from the Pi3 from a desktop on the internal network. Off I trot to purchase myself this fascinating little object and hooked it up I did indeed.
However, for the life of me I cannot figure out how to achieve the above scenario. I want the eth0 on a static ip of 192.168.2.10, 255.255.255.0 to access the Vigor 130 and the WiFi to connect to my Google WiFi.
Can you please help me with the various incantations and offerings to the dark gods I must perform to achieve this?