I wanted a netherrack&fire border around my house, but i couldn't get it to light. I places the Netherrack a block away from the wall of my house and 3 blocks above the ground. That is my suggestion. Also, Since rock materials don't burn as well, they make a good barrier (stone/brick fire place, not wood). You typically dont have much to worry about, but dont get carried away with the flint and still.