The Filter table is the most frequently used one. We will list all four along with the chains each table contains. Linux firewall iptables has four default tables. Typically, this is to accept it, drop it, or reject it (which sends an error back to the sender). The outcome, where a packet is sent, is called a target. Rules can block one type of packet, or forward another type of packet.
When a packet is received, iptables finds the appropriate table, then runs it through the chain of rules until it finds a match. Tables: Tables are files that join similar actions.Iptables identifies the packets received and then uses a set of rules to decide what to do with them. Data is broken up into smaller pieces (called packets), sent over a network, then put back together. Access to a terminal window/command line (Ctrl-Alt-T, Ctrl-Alt-F2).
