Computer Network Laboratory Group 5
˙Flow chart of iptables.
LINUX IPTABLE has 3 main tables, each table has their own several chains. The following are the functions of these 3 tables:
Filter: It is about the server itself.
INPUT: It is related with the packets that are going to enter our sever itself.
OUTPUT: It is related with the packets that are going out from our sever itself.
FORWARD: It forwards the packets to the LAN behind.
NAT: It is about the LAN behind.
PREROUTERING: The rules before routing decision.
POSTROUTERING: The rules after routing decision.
OUTPUT: It is about the packets transmitted out.
Mangle: It is related with router flags of special packets.
The simple version of flow chart of iptables: (It has been simplified by eliminating the mangle table.)
The complete version of the flow chart of the iptables.