  In this work we present a family of neural networks, the multi-layer
perceptron networks, and some of the algorithms used to train those networks
(we hope that with enough details and precision as to satisfy a mathematical
public). Then we study how to use those networks to solve a problem that arises
from the field of information security: the remote identification of Operating
Systems (part of the information gathering steps of the penetration testing
methodology). This is the contribution of this work: it is an application of
classic Artificial Intelligence techniques to a classification problem that
gave better results than the classic techniques used to solve it.
