Model :

Hardware Version :

Firmware Version :

ISP :

Guys - I would appreciate your views here, before I move to another router.
I cannot get it to accept a port forward to a host that is not on the same network as the LAN interface.

Firstly:
Model No. TD-W9970V1
Firmware Version:0.9.1 2.11 v0025.0 Build 170726 Rel.65343n
Hardware Version:TD-W9970 v1 00000001
Firewall is off
DSL Modem Router Mode (using with VDSL)

Configuration:
Internet > 9970 > UTM > devices
Static route on 9970 so that it knows to use the UTM to reach the 10.0.0.0/16 network

Problem:
I have the router setup with the lan side interface as 10.100.0.1/16
I need to forward a port to a device on 10.0.1.10/16 which is at the other side of the UTM (which is routing) and no NAT or port forwards in place (obviously).
I can ping from the inside lan device (10.0.1.10) to the 9970 LAN interface (10.100.0.1).

When I try and setup a port forward on the 9970 – it will only allow a destination IP to exist on the same network as the 9970 LAN interface, and as a result, give the error:

“Error code: 4937
The IP address is not in the same subnet with LAN IP address. Please input another one.”

Question:
Is there any way around this – like an alternative firmware version? I know of no reason why it should not be possible, but clearly open to ideas as to why it could not work!

Many thanks in advance

David