When you create a runNixOSTest machine, it is automatically configured with an eth0 interface which is NATed to the host and is assigned the 10.0.2.15 address. There is an additional default eth1 interface aswell which is a VLANs all the testing machines together. This is implemented here:
However what I can’t find is where the eth0 NATed interface is configured, does anyone know more information about this? Is this somehow configured by the qemu start command by chance?