Basic concept of iptable

Tables:
Table is category of functions provided by iptable. There are four choice: filter, nat, mangle and raw.
Chains:
Chain is the group of rules has the a common tag, for example input, output.
Matches:
Matche is a condition that use to decide which kind of actions need to be take by iptable.
Targets:
Targets are actions that could be used on packages base on which match it has met.