DXF Files 1000x larger than drawing

Every time I export to DXF then import into any other program the result is 1000 times larger, for example a square of 100mm per side comes out at 100 M per side. It is as if it is saving mm dimensions as meters. Is there some setting that I am unaware of?

I have solved the issue. I had misunderstood the function of the #box settings.