\begin{thebibliography}{1}

\bibitem{debian}
Debian.
\newblock \\http://www.debian.org.

\bibitem{netfilter}
Netfilter.
\newblock \\http://www.netfilter.org.

\bibitem{shorewall}
Shorewall.
\newblock \\http://www.shorewall.net.

\bibitem{andreasson}
Oskar Andreasson.
\newblock Iptables tutorial.
\newblock \\http://iptables-tutorial.frozentux.net/iptables-tutorial.html.

\bibitem{fiaif}
Anders Fugmann.
\newblock Fiaif is an intelligent firewall.
\newblock \\http://www.fiaif.net.

\bibitem{mnf}
Mandrakesoft.
\newblock Multi network firewall.
\newblock \\http://www.mandrakesoft.com/products/mnf.

\end{thebibliography}
