You know the expression, fight fire with fire.
The first time I heard that I thought the person who said it was saying it wrong because you fight fire with water or baking soda. Even though the person who said it, said it right, it still doesn't make sense to me.
Have you ever seen the fire department take a fire to a fire to put it out? What am I missing here?
Are they talking about gun fire? If they are they should say so and quit messing with my understanding of how things work.
Ah ... the wonderful English language.
You fight enemy fire by firing back.
In this sense, Danie has it exactly correct.