Firewalls

What is Firewalls?

In computing,a firewall is a network security system that monitors and control incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted network and an untrusted network,such as the internet.

Firewall Classification

First Generation/Packet Filtering firewall : It is used to control network access by monitoring outgoing and incoming packet and allowing them to pass or stop based on source and destination IP address,protocols and ports.It analyses traffic at the transport protocol layer.Packet firewalls treat each packet in isolation.

Second generation/state-full inspection firewall : They are able to determine the connection state of packet,unlike packet filtering firewall,which makes it more efficient.It keeps track of the state of networks connection travelling across it,so the filtering decisions would not only be based on defined rules.But also on packet’s history in the state table.

Third generation/Application layer firewall : They can inspect and filter the packets on any OSI layer,upto application layer.It has the ability to block specific content,also recognize when certain application and protocols (like HTTP,FTP) are being misused.

Next Generation Firewalls(NGFW) : They are being deployed these days to stop modern security breaches like advance malware attacks and application -layer attacks. It consists of Deep packet inspection,application inspection,SSL/SSH inspection and many functionalities to protect the network from these modern threats.

Types of firewalls

Host-based firewalls : It is installed on each network node with controls each incoming and outgoing packet.It is a software application or suite of applications,comes as a part of the operating system.They are needed because network firewalls cannot provide protection inside a trusted network. It protects each host from attacks and unauthorized access.

Network based firewalls : They function on network level.In other words,these firewalls filter all incoming and outgoing traffic across the network. It protects the internal network by filtering the traffic using rules defined on the firewall.