1. NETWORK SECURITY PRESENTed By SADASIVARAO.G

2. ABSTRACT:  Network security is a complicated subject, historically only tackled by well-trained and experienced experts.  However, as more and more people become ``wired'', an increasing number of people need to understand the basics of security in a networked world.  Some history of networking is included, as well as an introduction to TCP/IP and internetworking  We go on to consider risk management, network threats, firewalls, and more special-purpose secure networking devices.

3. CONTENTS:  Introduction to Networking  TCP/IP –The language of the model  Risk management  Firewalls  Secure network devices  Conclusion s  References

4. What is Network? Computer Networks can be defined as an Inter-connection of “autonomous computers”.  Uses : It can be used to many organizations to share, process and Exchange information. Like- Resource sharing,Realibility,Saving Money, Scalability,communication etc

6. Network A network is a group of two or more computer systems linked together. There are many types of computer Networks, including:

7.  Local_area Networks(LAN): The computers are geographically close together  Wide_area Networks(WAN):The computers are farther apart and are connected by telephone lines or radio waves.  Campus_area Networks(CAN): The computers are within a limited geographic area, such as a campus or military base.  Metropolitan_area Networks(MAN):A data network designed for a town or city.  Home_area Networks(HAN): A network contained within a user's home that

8. It is a measure taken to protect data During communication between the computers in a Network. The Network security is becoming more and more cricial as the volume of data being exchanged on the internet increases. Network security involves all activities that organizations, enterprises, and institutions undertake to protect the value and ongoing usability of assets and the integrity and continuity of operations. NETWORK SECURITY

11. PRIVACYAUTHENTICATION DATA INTEGRITY NON REPUDIATION Aspects of security

12. TCP/IP –The language of the model  IP  Open Design  TCP Guaranteed packet delivery  UDP lower overhead than TCP

13. The protocol is an ``open'' protocol, and anyone who wishes to implement it may do so freely. Engineers and scientists from all over the world participate in the IETF (Internet Engineering Task Force) working groups that design the protocols that make the Internet work. Open Design: This is the layer that allows the hosts to actually ``talk'' to each other. mapping the Internet address (such as 10.2.3.4) to a physical network address (such as 08:00:69:0a:ca:8f), and routing, which takes care of making sure that all of the devices that have Internet connectivity can find the way to each other. IP:

14. TCP TCP is a transport-layer protocol. It needs to sit on top of a network-layer protocol, and was designed to ride atop IP. TCP provides a connection-oriented,relible,byte steam service. oriented means the two application using TCP must establish a TCP connection with each other before Exchanging any data. Guaranteed packet delivery

15. UDP: UDP (User Datagram Protocol) is a simple transport-layer protocol. This protocol is used in place of TCP.UDP is connectionless protocol provides no reliability or flow control mechanisms. UDP serves as simple application interface to the IP IP Header UDP Header UDP Data IP Datagram UDP Datagram 20 Bytes8 Bytes UDP encapsulation

16. Risk management: It's very important to understand that in security, one simply cannot say ``what's the best firewall?'' There are two extremes: absolute security and absolute access The Game of Security The closest we can get to an absolutely secure machine is one unplugged from the network, power supply, locked in a safe, and thrown at the bottom of the ocean. Unfortunately, it isn't terribly useful in this state

17. Firewalls: Firewalls is nothing but a combination of hardware and software that Provides a security system,It can be used to prevent unauthorized access to an Internal network. It prevents direct communication between network and external computers By routing communication through a proxy server outside of the network

18. Firewalls Connection Ports Firewalls Packet filtering routers Application gateway Inside LAN Outside LAN Firewalls

19.  Secure network devices It's important to remember that the firewall is only one entry point to your network. Modems, if you allow them to answer incoming calls, can provide an easy means for an attacker to sneak around Secure Modems Crypto-Capable Routers Virtual Private Networks  Devices

20. S.M. Bellovin. Security Problems in the TCP/IP Protocol Suite. Computer Communication Review, Vol. 19, No. 2, pp. 32-48, April 1989. References:

21.  Conclusion s Security is a very difficult topic. Everyone has a different idea of what ``security'' is, and what levels of risk are acceptable. The key for building a secure network is to define what security means to your organization Many people pay great amounts of lip service to security, but do not want to be bothered with it when it gets in their way. It's important to build systems and networks in such a way that the user is not constantly reminded of the security system around him.

22. THANK YOU