NETWORK SECURITYNETWORK SECURITY USING IPTABLESUSING IPTABLES

TOPICS OF DISCUSSIONTOPICS OF DISCUSSION

NETWORK TRAFFIC IN PRESENT NETWORK TRAFFIC IN PRESENT SCENARIO !!SCENARIO !!

WHY WE NEED SECURITY ?WHY WE NEED SECURITY ? TYPE OF ATTACKS & WAYS TO TACKLE IT TYPE OF ATTACKS & WAYS TO TACKLE IT IPTABLES : HOW & WHERE TO USEIPTABLES : HOW & WHERE TO USE PRACTICAL APPLICATIONPRACTICAL APPLICATION LATEST DEVELOPMENTS & RESEARCH LATEST DEVELOPMENTS & RESEARCH

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NETWORK TRAFFIC & INTERNET USERS

Network Security: An OverviewNetwork Security: An Overview

Any action that compromises the security Any action that compromises the security of information.of information.

four types of attack –four types of attack –

1. Interruption

2. Interception

3. Modification

4. Fabrication

TOOLS FOR SECURITYTOOLS FOR SECURITY CRYPTOGRAPHY (data)CRYPTOGRAPHY (data) KERBEROS (servers)KERBEROS (servers) PGP (PGP ( E-mails)E-mails) IPSec (rout-net)IPSec (rout-net) SSL (higher level)SSL (higher level) FIREWALLS FIREWALLS IPTABLES IPTABLES

iptables is the name of the user space tool by which administrators create rules

for the packet filtering and NAT modules

Iptables is often used to refer to the entire infrastructure, including netfilter,connection tracking and NAT, as well as the tool itself. iptables is a standard part of all modern Linux distributions

Iptables where and how to useIptables where and how to use Ip Iptable “Tables”table “Tables”

actually, multiple tables, each supporting actually, multiple tables, each supporting several chains are used.several chains are used.

each table handles a different purpose each table handles a different purpose (we cannot see these tables).(we cannot see these tables).

1. filter table1. filter table 2. NAT table2. NAT table 3. Mangle table 3. Mangle table

Iptables setup & loadingIptables setup & loading

each Linux distribution takes different approach each Linux distribution takes different approach to manage firewall.to manage firewall.

in Red-hat linux all rules are stored in the file in Red-hat linux all rules are stored in the file - /etc/sysconfig/iptables- /etc/sysconfig/iptables

To turn on firewall ( as root) To turn on firewall ( as root)

/sbin/service iptables on/sbin/service iptables on

/sbin/service iptables save/sbin/service iptables save

/sbin/service iptables load/sbin/service iptables load

Firewall policyFirewall policy

to protect the firewall itself we want to to protect the firewall itself we want to restrict communication destined directly to restrict communication destined directly to the firewall very strictly.the firewall very strictly.

to do the above …………….to do the above ……………. (in SSH ) (in SSH ) iptables–A INPUT-s 192.168.50.0/24iptables–A INPUT-s 192.168.50.0/24 -p tcp –dport 22 –j ACCEPT-p tcp –dport 22 –j ACCEPTIptables –A INPUT –j REJECT –reject-with Iptables –A INPUT –j REJECT –reject-with

icmp-hostprohibited icmp-hostprohibited

NOW LET US SEE ………………………….

SOME PRACTICAL IMPLEMENTATION

OF IPTABLES (HOW ONE CAN HACK THE NETWORK

SECURITY) AND HOW IPTABLES ARE EFFECTIVE.