The document provides an overview of firewalls, explaining their role as network devices that block specific types of network traffic to create a barrier between trusted and untrusted networks. It outlines various types of firewalls, including packet filtering, stateful, deep packet inspection, application-aware, and application proxy firewalls, each with unique functionalities and methods of filtering network traffic. The information details how these firewalls operate and the security measures they implement to protect networks.

2. Content
 What Is Firewall?
 Types Of Firewall
 Packet Filtering Firewall
 Statefull firewall
 Deep packet inspection firewall
 Application-aware firewall
 Application proxy firewall

3. What Is Firewall?
The word firewall means a network device that
is used to block certain types of network traffic.
Basically, firewall forms a barrier between a trusted
and an untrusted network.

4. Types Of Firewall
Packet filtering firewall
Stateful firewall
Deep packet inspection
firewall
Application-aware firewall
Application proxy firewall

5. Packet Filtering Firewall
In this type of firewall, there are security rules that block
traffic based on IP address and IP protocol.
Filtering Rules are based on information contained in a
network.
•Source IP address
•Destination IP address
•Source and destination transport level address
•IP protocol field
•Interface

6. Packet Filtering Firewall

7. Statefull Firewall
Statefullfirewall tracks the state of network connections
when it is filtering the data packets.
These firewalls can watch the traffic streams end to
end.
Statefull firewalls are aware of the communication path
and can implement various IP security functions such as
tunnels or encryptions.

8. Statefull Firewall

9. Deep Packet Inspection Firewall
Deep packet inspection is a form of packet
filtering usually carried out as a function of your firewall.
The process of analyzing these packets, known as deep
packet inspection (DPI), is used every day by enterprises
and internet service providers (ISPs) to detect and
prevent cyberattacks, combat malware, optimize servers
to reduce overhead, and analyze user behavior.

10. Deep Packet Inspection Firewall

11. Application-Aware Firewall
The application-aware firewall is a kind of technology
that redefines the way the corporate networks are
secured.
The Application-aware firewall inspects the traffic and
blocks traffic based on applications, category,
application-family or application-group.

12. Application-Aware Firewall

13. Application-Proxy Firewall
An application proxy or application proxy server
receives requests intended for another server and acts as
the proxy of the client to obtain the requested service.
The Application proxy server when the client and the
server are incompatible for direct connection.

14. Application-Proxy Firewall