1. DEPARTMENT OF MICROBIOLOGY
AND BIOTECNOLOGY
PRESENTED BY
SAPNA KUMARI
I MSc ( MICROBIOLOGY)

2. NETWORK SECURITY
 It is the control of unwanted intrusion into or damage to
communications on our organizations computer network.
 It supports essential communications which are necessary to the
organizations mission and goals.
 It includes elements that prevent unwanted activities while
supporting desirable activities.
 It involves the authorization of access to data in a network which
is controlled by the network administrator.
It involved in organizations , enterprises and other types of
institutions.

3. SECURITY OBJECTIVES
 Confidentiality
 Integrity
 Authentication
 Authorization
 Non repudiation
 Availability
 Privacy

4. GOALS OF NETWORK SECURITY
 Ensures the confidentiality of resources
 Protect the integrity of data
 Maintain availability of the IT infrastructure
 Ensure the privacy of personally identifiable data
 Enforces access control
 Monitor the IT environment for violations of policy

5. GROUP POLICY
 It is the feature of the Microsoft windows NT family of operating
systems.
 It controls the working environment of user accounts and
computer accounts.
 It provides the centralized management and configuration of
operating systems, applications and users settings in an ACTIVE
DIRECTORY environment.
It controls what users can and cannot do on a computer.

6. TYPES OF GROUP POLICY
 Account policies
 Local policies
 Event log
 Restricted groups
 Systems services
 Registry
 File system
 Public key policies
 Internet protocol security policies

7. TYPES OF GROUP POLICY( cont’d)
ACCOUNT POLICIES
Account policies are the first subcategory of security settings.
The account policies include :
• Password policy
• Account lock out policy
LOCAL POLICIES
It is the second subcategory of security policy. It includes
security settings.

8. EVENT LOG POLICIES
It is used to control the settings of the application , system
and security event logs on local computers.
RESTRICTED GROUPS
It contain a list of members of specific groups whose
membership are defined centrally as part of the security policy.
It can be used to manage membership in the built in groups.
SYSTEMS SERVICES POLICIES
It offer a mechanism for potential exploitation by
intruders who can take over the services or use the services as an
entry point to gain access to computers and computer network
resources.

9. REGISTRY
It is used to configure security and control security auditing for registry keys
and their subkeys.
FILE SYSTEM
It is used to configure the security for files and folders . It control security
auditing of files and folders.
PUBLIC KEY POLICIES
It add a new encrypted data recovery agent and set up automatic certificate
requests. It can also manage the lists of trusted certification authorities.

10. IP SECURITY POLICIES ON ACTIVE DIRECTORY
It tell the server how to respond to a request for IPsec communications .
The server might require secure communication, permit secure
communication, or communicate without using Ipsec.

11. OSI Reference Model
 Consists of seven layers.
 Each layer provides a set of functions to the layers above and relies on
the functions provided by the layers below.
 Each layer communicates with its peer layer on the other node
(protocols).
 The layer boundaries (interfaces) should be designed in such a way as to
minimize the information flow between the boundaries .
 The main idea is to have independent standards for different layers so
that changes to one would not cause changes in other layers.

12. OSI Reference Model (cont’d)

13. LAYER 7 : APPLICATION LAYER
It is the user interface to your computer or programs.
Eg: word processor , e-mail application etc.
LAYER 6 : PRESENTATION LAYER
It acts as the translator between systems, converting application
layer information to a common format understandable by different
systems.
LAYER 5 : SESSION LAYER
It manages the connections or service requests between
computers.
LAYER 4 : TRANSPORT LAYER
It prepares data for delivery to the network.

14. LAYER 3 : NETWORK LAYER
It is where IP addressing and routing happen. Data at this layer is
considered a “ packet” .
LAYER 2 : DATA LINK LAYER
It handles the reliable sending of information. Media access control is a
component of layer 2. Data at this layer would be reffered to as a “FRAME”.
LAYER 1 : PHYSICAL LAYER
It is composed of the objects that you can see and some that you cannot
, such as electrical characteristics.

15. A firewall :
Acts as a security gateway
between two networks
Usually between trusted
and untrusted networks
(such as between a
corporate network and the
Internet)
Decides whether to pass,
reject, encrypt, or log
communications (Access
Control)
Internet
Corporate
Site
Corporate Network
Gateway
“Allow Traffic
to Internet”

16. Why Firewalls are Needed
 Prevent attacks from untrusted
networks
 Protect data integrity of critical
information
 Preserve customer and partner
confidence

17. Evolution of Firewalls
Packet
Filter
Application
Proxy
Stateful
Inspection
teful

18. TYPES OF FIREWALLS
 PACKET FILTERS
APPLICATION LAYER GATEWAYS
STATEFUL INSPECTION

19. PACKET FILTER
 The first paper on firewall was published in 1988.
 This was the first generation of highly involved and technical internet
security.
 It was developed by BILL CHESWICK AND STEVE BELLOVIN.
 It act by inspecting the “PACKET” which transfer between computers on the
internet.
 If a packet matches the filters set of rules, the packet filter will drop or
reject the packet.
 It work mainly first 3 layers of the OSI model, which means most of the
work is done between the network and the physical layer.
 It is the simplest type of firewalls.

20. APPLICATION PROXY
It is called as also known as PROXY FEREWALL.
The key benefit of the application layer filtering is that it can “
understand” certain applications and protocols( SUCH AS WEB
BROWSING).
It can detect if an unwanted protocol is sneaking through on a non
standard port or if a protocol is being abused in any harmful way.
It mainly works on layer 7 of the OSI model.
When a connection comes into an application gateway, the firewall
completes the connection and creates a new connection from the firewall
to the final destination . In a sense , a true proxy doesnot route network
traffic. It buffers traffic, modifies the data , if necessary then sends the
data to the destination.

21. STATEFUL INSPECTION
It was developed in 1989- 1990.
It was developed by DAVE PRESSETTO, JANARDAN SHARMA AND KSHITY
NIGAM.
It is also called as CIRCUIT LEVEL FIREWALLS.
It work upto layer 4 of OSI model( transport layer).
It used to record all the connection passing through it and determines whether
a packet is the start of the new connection, a part of an existing connection or
not a part of any connection.
It allows the firewall to have a complete application awarness without breaking
the client / server model.

22. Firewalls and Proxy Servers

23. LIMITATION OF FIREWALLS
 It cant protect the attacks that don’t go through the firewall.
 It cannot protect the morons which are present inside the network.
 Firewall policies must be realistic and reflect the level of security in the
entire network.
 It has no concept of the value or sensitivity of the data ,it is transferring
between networks and therefore,it cannot protect information on that
basis.

24. CONCLUSION
 Network security is the ongoing process of
maintaining the privacy of data that should
remain private.
 Group policy contains the goals, objectives and
standards for security activities.
 A firewall is a network security product that acts
as a barrier between two or more network
segments.