An internet protocol address is a numerical label assigned to devices connected to a network that uses IP for communication. IP tables is the basic firewall software used in Linux, which uses chains and rules to filter packets and decide whether to process or discard them based on the packet type. The three main tables in IP tables are the filter table for handling network packets, the nat table for altering packets during connection creation, and the mangle table for specific packet alterations.

2.  An internet protocol address is a numerical
Label assigned to each device connected network that
use the internet protocol for communication.
 The address is made of 32 binary bits which can be
divisible into network portion and host portion with
the help of a subnet mask.

3.  The basic firewall software used in Linux is called
IP tables.
 IP tables is a command –line firewall utility that
uses policy chain allow .when a connection
established itself on the system the IP tables
looks for a rule in its list match it . if don’t find it
show default action.
 We can call basic firewalls for Linux . The firewall
system is normally installed and shoe the input
and output packets.

4. o The default structure of IP Tables is like:
“Tables which has chains and the chains which
contain rules”
o Table Chains Rules
o The rules are defined to control the packets
for input/output.

5. o The kernel has the ability to filter packets and
decide based on the rules what to do with each
packet.
o IP filtering is simply mechanism that decides which
types of IP datagram will be processed normally
which will be discarded
o Packet filtering uses a list of rules for filtering.

6.  The three built-in tables with chain rules.
They are follows:
o Filter: The default tables for handling network
packets.
o Nat: Used to alter packets that create a new
connection.
o Mangle: used for specific types of packet
alteration.