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.