[buzzbaiter]

First of all foxes are primarily dawn/dusk hunters so any daylight activity is odd. Secondly they are very shy. An aggressive fox to me suggests its sick.

From Humane Society:

Signs of rabies in animals
In the “furious” form, wild animals may appear to be agitated, bite or snap at imaginary and real objects, and drool excessively. In the “dumb” form, wild animals may appear tame and seem to have no fear of humans.

There are other signs, such as the animal appearing excessively drunk or wobbly, circling, seeming partially paralyzed, disorientated, or self-mutilating. However, most of these signs can also be indicative of other diseases like distemper or lead poisoning. There are few behavioral signs that are telltale of rabies alone.