In this chapter, we are not going to concentrate on this topic. First, many aspects of network traffic analysis were already covered in Chapter 4 when discussing attack indications. Secondly, there are two excellent books on this topic, which I would gladly recommend to anyone - [Northcutt1-00] and [Cooper1-01]. In these books, all aspects of network-traffic analysis and detecting attack indications are covered in great detail. So let's here discuss some topics that are rarely discussed in various publications or other sources of information.