Unable to get Simulator 7.3.6 to work correctly

I have installed the 7.3.6 simulator onto a Linux host running RedHat that sits on top of Hyper-V.

The Linux host  has 2 interfaces.

1 I have put downm and is in promiscuous mode.

I have setup the simulator fine, but cannot get any network connectivity.

Does anyone have any ideas regarding subnets, netmasks etc .... 

I originally created dns entries for 2 new entries for ns0 and ns1 on the simulator, and selected the down interface on the underlying Linux host during the setup.

That did not work.

So, I tried using the same I.P address on ns0 as the down interface on the lInix host.

Still doesn't work.

Is there something that needs to be set on Hyper-V I have missed, or on the Linux host ?.

Thanks.