Network Security is needed to prevent
hacking of data and to provide authenticated data
transfer. Network Security can be achieved by
Firewall. Firewall is a hardware or software
device designed to permit or deny network
transmissions based upon a set of rules and
regulation. It is frequently used to protect networks
from unauthorized access.A firewall is typically
placed at the edge of a system and acts as a filter
for unauthorized traffic. But conventional firewalls
rely on the notions of restricted topology and
controlled entry points to function. Restricting the
network topology, results in difficulty in filtering of
certain protocols, End-to-End encryption problems
etc.Sodistributed firewalls are used which allow
enforcement of security policies on a network
without restricting its topology on an inside or
outside point of view. Distributed firewalls secure
the network by protecting critical network
endpoints, exactly where hackers want to
penetrate. It filters traffic from both the Internet
and the internal network. They provide unlimited
scalability and also they overcome the single point
of failure problem presented by the perimeter
firewall.
This paper is a literature review paper,
dealing with the general concepts such distributed
firewalls, its requirements and implications and
introduce, its suitability to common threats on the
Internet, as well as give a short discussion on
contemporary implementations. A distributed
firewall gives complete security to the network.