Netfilter Hooks in the Linux Kernel
http://hmyblog.vmmatrix.net/lna/0131777203_ch19lev1sec3.html
想要徹底了解 Netfilter NAT的 kernel data structure, 看這幾篇文章就對了
http://hmyblog.vmmatrix.net/lna/0131777203_ch21.html
http://hmyblog.vmmatrix.net/lna/0131777203_ch21.html
http://hmyblog.vmmatrix.net/lna/0131777203_ch21.html
packet flow in the linux kernel
http://imagestream.com/~josh/PacketFlow-new.png
http://www.shorewall.net/images/Netfilter.png
http://dmiessler.com/images/DM_NF.PNG