Hello,
Please let me know if I understood, are you trying to connect both interfaces of the same device? i.e. Wifi and Ethernet from the same computer?
It's possible to do the bridge mode and is needed to bind to an end device MAC address.
So, the bridge mode disable the DHCP server, if you need to access from another LAN IP, it won't be possible.
By the way, RUT240 has the Passthrough mode, in this case, the DHCP can be used as static or dinamyc server.
You can take a look to this link. https://wiki.teltonika-networks.com/view/RUT240_Mobile#Mobile_Configuration
Anything let us know.
Regards