The document presents an overview of firewalls, explaining their purpose as security devices that filter incoming and outgoing network traffic based on set rules. It covers the history, types, and advantages and disadvantages of both hardware and software firewalls, emphasizing the need for both for optimal security. Key types of firewalls are packet-filtering, circuit-level, and application-level, each with distinct operational characteristics and use cases.

1. SEMINAR ON
FIREWALL
PRESENTED BY :- IIITU15114

2. CONTENT
• What is Firewall ?
• History
• Design Goal of Firewall
• Software Firewall vs Hardware Firewall
• Types of Firewall
• Conclusion

3. WHAT IS FIREWALL ?
• A Firewall is a program or hardware device that filters the information coming through internet
into our private network or computer system.
• It act as a barrier between local area network and the other networks.
• It monitors and control the incoming and outgoing network traffic based on predefined security
rules.
• It can be of types :
• Hardware Firewall
• Software Firewall
• Most personal computers and their operating systems include software based firewalls for
protecting the computer from the many types of threats.
• Most routers that transmit data between networks contain hardware firewalls which make the
network more secure.

4. HISTORY OF FIREWALL
• Firewall technology first began to emerge in the late 1980s.
• The idea of Firewall formed after major internet security breached happened in
1980.
• One of the first major attack on Internet Security is Morris Worm which is
distributed through email over the internet . It affected nearly 2000 computers
and 6000 UNIX machines in 15 hours. It almost take 2 days to remove completely
this virus.
• After this attack internet community began to collaborate on new ideas , system
and software to make internet safe .
• The first paper on Firewall Technology was published in 1988 by Jeff Mogul
known as packet filter firewalls (First generation of Firewall ).

5. CONT…
• From 1980-1990 two colleagues from AT&T Bell Laboratories, Dave Presetto and
Howard Trickey, developed the second generation of firewalls known as circuit
level firewalls.
• Bill Cheswick at AT&T laboratories and Marcus Ranum described a third
generation firewall known as application layer firewall, also known as proxy-based
firewalls.
• The first commercial Firewall was launched in 1991 named DEC SEAL.

6. DESIGN GOAL OF FIREWALL
• The first design goal for a firewall is that collectively the sum of all the network
traffic from internal to external must go through the firewall physically cutting off
all access to the local network except via the firewall.
• The second design goal would be only authorized traffic which is predefined by
the local security policy will be allowed to proceed.
• The last design goal is that the firewall itself is resistant to penetration inclusive is
a solid trustworthy system with a protected operating system.

7. CATEGORIES OF FIREWALL
• There are two categories of Firewall:-
• 1. Hardware Firewall:-
• These are the Firewall which are integrated into the hardware devices like
Routers, Broadband modems ,etc.
• They typically deal with the packet filtering which means they scan the
packet header and determine the source and destination IP address and
check the packet according to the predefined rules and make the decision
whether to allow or block them.
• These firewalls do not need lot of configuration as most of the rules are
predefined and built in and they do packet filtering based on them.
• Example :- Cisco Hardware uses “Cisco Protect Link Security Solutions”

8. ADVANTAGE OF HARDWARE FIREWALL
• Speed :-
• Hardware Firewall has faster response time, so it can handle more traffic load.
• Security :-
• This Firewall has their own operating system so they are less prone to attack and they
have more enhanced security controls.
• No Interference :-
• As it is an isolated network component , it can be managed better and does not load
or slow down with other applications. It can be stopped or reconfigured with
minimum interference to the network.

9. SOFTWARE FIREWALL
• Software firewalls are programs which are installed on individual servers or an
individual host .
• They intercept each connection request and then determine whether the request is
valid or not.
• They can easily distinguish between application programs and can control what they
can sent and receive over the internet.
• They provide better control over its function and protection features.
• Examples :- Windows Firewall , Zone Alarm
• Even most of the antivirus software includes firewall.

10. ADVANTAGE OF SOFTWARE FIREWALL
• They are easy to configure and setup.
• Through Software firewall we can restrict some specific application from the
internet. This makes it more flexible.
• They provide users complete control on their internet traffic through a nice user
friendly interface that require little knowledge.

11. TYPES OF FIREWALLS
• There are three common types of Firewalls:
• 1. Packet-filtering Firewall
• 2. Circuit-level Firewall
• 3. Application-level Firewall

12. PACKET-FILTERING FIREWALL
• Packet-Filtering Firewalls works at the network level of OSI Model
• These firewall monitor the both incoming and outgoing packets and applies a set of rules to each
packet and than determine whether to discard or to allow it.
• They actually determines the information available at transport layer to make decisions.
• What they Inspect in Packet Header?
• Packet Filtering checks both the source and destination IP address.
• It checks the source and destination protocols like UDP(User Datagram Protocol) and
TCP(Transmission Control Protocol).
• It also check the source and destination port address.
• Packet Filtering is also know as Static Filtering.

13. CONT..
• Advantages:-
• It is cost-effective means of security.
• It has effective defense against attacks from computers outside a local area network
(LAN) as most of the routing device have integrated filtering capabilities.
• It has high speed.
• Disadvantages:-
• Difficulty in setting up packet filtering rules as it requires command line commands.
• Once rules are setup ,it is hard to test them.
• Lack of Authentication
• They do not support Complex rule based models.

14. CIRCUIT LEVEL GATEWAY FIREWALL
• The circuit level gateway firewalls work at the session layer of the OSI model.
• They monitor TCP handshaking which is used to establish connection and determine
if a requested session is valid or not.
• They hide the information about the internal network. All the information passing
through circuit-level gateway firewall to internet appears that it originated from circuit
level gateway. There is no way for a remote host to determine the internal IP address
of a network
• It use network translation technique as it translate all the private IP address
originating form clients inside the network to public IP address available through ISP
and then send it to the outside world(internet).
• So all the packets are tagged with Public IP address and all the internal IP address will
never get exposed to potential intruders.

15. CONT..
• Advantages:-
• Circuit level gateways are comparatively inexpensive .
• They provide Anonymity to the private network.
• Disadvantage:-
• Circuit level Gateways do not filter Individual Packets. After Establishing a
Connection, an Attacker may take advantage.

16. APPLICATION LEVEL GATEWAYS FIREWALL
• It work on the Application layer of the OSI model and provide protection for a
specific Application Layer Protocols.
• It would work only for the protocols which are configured. For example, if we
install a web proxy based Firewall than it will only allow HTTP Protocol Data.
• These firewall use proxies for various application. Both the client and the server
connect to these proxies instead of connecting directly to each other. So, any
suspicious data or connections are dropped by these proxies.
• They are also called proxy servers.

17. CONT..
• Advantage:-
• Application level firewalls can also be configured as Caching Servers which in turn increase
the network performance and makes it easier to log traffic.
• Easy to log and audit all incoming traffic.
• Direct connections between internal and external hosts are disallowed.
• User-level authentication is supported.
• Disadvantage:-
• Slower than packet filters.
• Every possible type of connection can not be supported .
• For each protocol, such as HTTP, SMTP, etc., requires its own proxy application
• Application firewalls typically require clients on the network to install specialized software
or make configuration changes to be able to connect to the application proxy.

18. CONCLUSION
• Firewall is the essential part of the internet if you want internet safer as it blocks
any unwanted request from getting into your network or personal computer.
• We have to use both hardware and software firewall because Neither of them
individually provide better security.

19. REFERENCES
• https://en.wikipedia.org/wiki/Firewall_(computing)
• http://nhprice.com/tutorial-of-firewall-types-and-their-advantages-and-
disadvantages.html
• https://www.techopedia.com/definition/4038/packet-filtering