A firewall monitors and controls incoming and outgoing network traffic based on security rules, acting as a barrier between trusted and untrusted networks. There are various types of firewalls including packet filters, proxy firewalls, application-layer firewalls, and stateful firewalls. Successful firewall implementation involves defining security needs, researching solutions that meet those needs, and properly installing, configuring, and maintaining the chosen firewall.

1. E-Commerce Progression
TOPIC: FIREWALL
Definition: What is Firewall?
A firewall is a network-security system, which monitors and controls the
incoming and outgoing network traffic based on predetermined security rules.
Firewalls are often categorised as either network firewalls or host-based
firewalls.
A firewall acts as a barrier between a trusted network and and an untrusted
network. This means that the only traffic allowed onto the network is defined in
the firewall policy; all other traffic is denied.
Types: Various Firewalls
Firewalls may vary in types depending on the origination of communication,
interception point, communication types being traced.
1. Packet Filters: It was one of the earliest firewall, inspecting the packets
that are transferred between computers on the Internet.When a packet
passes through a packet-filter firewall, its source and destination address,
protocol, and destination port number are checked against the firewall's rule
set.Packet-filter firewalls work mainly on the first three layers of the OSI
model (physical, data-link and network layer).
2. Proxy Firewalls: This firewall acts between systems, and proxy
firewalls keep direct connections from being established between both
sides. Firewall proxy serversoperate at the firewall's application layer,
acting as an intermediary for requests from one network to another for a
specific network application.
3. Application-Layer Firewalls: Application-layer firewalls work on
the application level of the TCP/IP stack, generally intercepting all packets

2. travelling to or from an application. The key benefit of application-layer
filtering is the ability to block specific content, such as known malware or
certain websites, and recognise when certain applications and protocolssuch
as HTTP, FTP and DNS -- are being misused.
4. Stateful Firewalls: In order to recognise a packet's connection state, a
firewall needs to record all connections passing through it to ensure it has
enough information to assess whether a packet is the start of a new
connection, a part of an existing connection, or not part of any connection.
Role in Security:
The firewall controls connections coming into your network so that only the
connections that are allowed can get through. It is same like the watchman will
let only those people go who lives in the building and a list of authorised guests,
which is known as access policy.
An access policy is simply a set of rules that determine who gets in or out of
your network and who doesn't. Firewall access policies are created by firewall
administrators, who are IT experts that know and understand how to setup the
firewall to protect your network.
Firewalls are also used to segment your network into places called zones. Zones
are smaller chunks of your network that share similar attributes. Going back to
our fancy building analogy, the watchman knows that residents go to the
elevators, employees go to the door on the right, guests go to the registration
desk to check in, and the bad crowd stays out.
Similarly a firewall protects your network. It directs and controls traffic on your
network using various access policies that may apply to the various zones.
Issues in Implementation of Firewall:

3. • The major issue that most firms faced was make make-or-buy decision. In the
past, the firewalls were constructed according to the firm’s requirements
which required significant amount of corporate time and effort. Therefore, it
became unviable for the corporates.
• The other issue was that there were array of choices of firewall in the market,
which needed the corporate managers to be careful in choosing the right one
for the firm.
• Another issue was that, the companies transaction process was slowed down
as the firewall examines all the which passes through it.
Successful Implementation of Firewall:
A firewall keeps the network, and everything in it, as secure as possible from
potential attacks.Below are three ways to ensure that the implementation of
your firewall is successful:
• Define security needs: Before installing a firewall solution, it is helpful
to first define exactly the level of security necessary for your organisation.
Examine any existing solutions and note what currently works, what doesn’t
work, and what areas need to be improved.
• Research solutions that match the specified needs: Only once a
business has defined what it needs from a firewall/managed security service
can the process of researching solutions begin. Choose a vendor who has a
reputation for providing quality and efficient service.
• Installation, configuration, and maintenance of the
firewalls: Once a vendor has been chosen, the final step in setting up your
firewall is the actual implementation. The IT provider you have chosen will
install the solution in your environment, covering all of the areas you deemed
necessary in your earlier assessment.