I want to thank the following people and organizations who had helped me, directly or not, to make this document possible:
My wife Cielo and my sons Jose, Dario and Gustavo by their patient and support.
Linux Documentation Project for publishing and uploading my document.
The site http://www.docum.org drived by Stef Coene that give me some ideas for writing this document.
Paul "Rusty" Rusell who write the kernel firewall code, the excelent package iptables and the associated library libiptc.
Harald Welte who write the utility iptables-save.
Alexey Kuznetsov who write the kernel queue discipline code and the excelent package iproute2.
Tabatha Persad from the Linux Documentation Project who revised my english syntax and writing, gave me several ideas to improve the content and encouraged me to learn and use DocBook to write the final version of this document.