In this chapter, I am not going to give you a list of known problems and their solutions. A lot of ideas in the HOWTOs do that for you. I am not going to give you details of the system in which you need to find the solution yourself. I hope I did that in the first part of the book. What I am going to do here is to talk about the techniques and tricks that I’ve learned over the years to track down the cause of problems. Also, I’ll talk about what you can do to find out where the answer is, if you don’t have the answer yourself.