Iptables network packet flow in Graphviz
This is a network packet flow trough Iptables tables and chains graphed in Graphviz open source graph visualization software. See Traversing of tables and chains chapter in "Iptables Tutorial" book by Oskar Andreasson for full details.
Image is generated by the following command:
dot -T png -o iptables-packet-flow.png < iptables-packet-flow.gv
Note: Iptables Tutorial has not been updated for quite a while.