FIREWALLS ON MAC OS

FIREWALL IS USED TO PROTECT OUR INTERNAL NETWORK FROM EXTERNAL HACK AND ACCESS.

TYPES OF FIREWALL:-

1.)HARDWARE FIREWALL ->> PIX DEVICES
2.)SOFTWARE FIREWALL ->> WHICH WE GET FROM THE MANUFACTURE OS AND OTHER THIRD PARTY SOFTWARE.

WE USE IPTABLES ->. IPTABLES IS A PACKAGE USED TO CONFIGURE LINUX FIREWALL.

NOTE:-THE PACKETS FLOW FROM EXTERNAL TO INTERNAL AND VICE VERSA.

DECISION TYPE FOR INPUT,OUTPUT AND FORWARD CHAIN

1.)INPUT CHAIN ->> We use input chain to check packets those are come from our internal network.

2.) ->> We use output chain to check the packets those are come from our internal network.
3.) ->> we use forward chain to check whether the packets is check or not.


IPTABLES RULE'S

SOURCE ADDRESS->DESTINATION ADDRESS->PORT NO.->CONNECTION->FLAG->DATA->ENCRYPTION


1.)#iptables -l (TO DISPLAY FIREWALL RULE)
2.)#iptables -F (FLUSH ALL RULES)
3.)#iptables -N test (TO MAKE NEW IP RULE)
4.)#iptables -X test (TO REMOVE ANY RULE)
5.)#iptables -P INPUT ACCEPt (TO MAKE PRIMARY input CHAIN)
6.)#iptables -A(add) INPUT -s(source ip) 192.168.x.x -J(jump) ACCEPT/DENY
7.)#iptables -A INPUT -p 192.168.x.x --dport 80 -J ACCEPT (to rule on port)



TO DENY PING RESPONSE
#iptables -A INPUT -S 192.168.1.4 -p icmp --icmp -type echo-request -J DROP/REJECT