This is not a homework question. I'm just having trouble understanding when it's appropriate to apply Gauss's law or not, and under what conditions does it fail. For example, suppose I have two point charges forming a dipole. If I draw a cylinder around them, then the total charge enclosed is zero, implying that the field is zero. However, this is obviously not true for a dipole. So would I be using Gauss's law incorrectly in this case, or does it not applying to discontinuous charge distributions, or what?