1. NETWORK SECURITY USING IPTABLES

2. TOPICS OF DISCUSSION NETWORK TRAFFIC IN PRESENT SCENARIO !! WHY WE NEED SECURITY ? T TYPE OF ATTACKS & WAYS TO TACKLE IT I IPTABLES : HOW & WHERE TO USE P PRACTICAL APPLICATION L LATEST DEVELOPMENTS & RESEARCH

3. NETWORK TRAFFIC & INTERNET USERS

4. Network Security: An Overview Any action that compromises the security of information. Any action that compromises the security of information. four types of attack – four types of attack – 1. Interruption 2. Interception 3. Modification 4. Fabrication

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

6. 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

7. Iptables where and how to use Ip table “Tables” actually, multiple tables, each supporting several chains are used. actually, multiple tables, each supporting several chains are used. each table handles a different purpose (we cannot see these tables). each table handles a different purpose (we cannot see these tables). 1. filter table 1. filter table 2. NAT table 2. NAT table 3. Mangle table 3. Mangle table

8. Iptables setup & loading each Linux distribution takes different approach to manage firewall. each Linux distribution takes different approach to manage firewall. in Red-hat linux all rules are stored in the file - /etc/sysconfig/iptables in Red-hat linux all rules are stored in the file - /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

9. Firewall policy to protect the firewall itself we want to restrict communication destined directly to the firewall very strictly. to protect the firewall itself we want to restrict communication destined directly to the firewall very strictly. to do the above ……………. to do the above ……………. (in SSH ) (in SSH ) iptables–A INPUT-s 192.168.50.0/24 iptables–A INPUT-s 192.168.50.0/24 -p tcp –dport 22 –j ACCEPT -p tcp –dport 22 –j ACCEPT Iptables –A INPUT –j REJECT –reject-with icmp-hostprohibited

10. NOW LET US SEE …………………………. SOME PRACTICAL IMPLEMENTATION OF IPTABLES (HOW ONE CAN HACK THE NETWORK SECURITY) AND HOW IPTABLES ARE EFFECTIVE.