In computing, a firewall is a security for network. It monitors and controls incoming and outgoing network traffic. It is totally based on predetermined security rules. A firewall typically establishes a barrier between a trusted network and untrusted network like internet. Generally, Firewalls have been popular of defense in network security for over 25 years. It establish a barrier between secured internal network such as the internet. Comparatively, A firewall can be hardwaresoftware or both.

History of Firewall

The term firewall originally refers as a wall intends to confine a fire with a line. Later uses refer to similar structures like metal sheet separating the engine of vehicle. The term was applied in the late 1980s to network technology. It emerges when the market was fairly new in terms of its global use. The network security router is used in the late 1980s. Because they already apply filtering to packets crossing them. Before it was used in real life computing, the term appeared in the 1983 a computer hacking movie which inspire us later.

How Firewall Works

A firewall carefully analyze incoming traffic. That traffic is based on pre-established rules and filter traffic. That filter traffic coming from unsecured or suspicious sources to block attack. Generally, Firewalls guard traffic at a computer’s entry point which is known as a ports. Generally, This is the place where the information is exchange with external devices.  Think of a IP addresses as houses. port numbers as rooms within the house. as an i.e. Only trusted members are allow access certain rooms. A house owner can access all rooms but a child or a guest can access only certain rooms.

A software firewall is a kind of program which is installs on each computer and regulates traffic via port numbers and apps. While a physical firewall is a piece of equipment which is installs between our network and gateway. A packet filtering firewalls is a most common type of firewall. It examines a packets and prohibit them from passing via security rule set. This type of firewall checks the packet’s source and destination. Generally a packet filtering firewalls are divided into two categories one is stateful and another is stateless.

Types Of Firewall

Next generation firewall

combination of traditional firewall technology with additional function. just like encrypted traffic inspection, anti-virus. It includes deep packet inspection (DPI). While some basic firewall only look at packet headers. It enables users to more effectively categorize, identify.


Proxy firewall

Filter network traffic at the application level. The proxy acts an intermediately between two systems. A client must need to send a request to the firewall. Where It is evaluate against a set of security rules. Generally, proxy firewalls monitor traffic for layer 7 protocols like HTTP and FTP.


Network address translation firewall

It allows multiple devices with independent network addresses to connect using single IP address. Generally, It keeps individual IP addresses hidden. An attackers who scanning a network for a IP address can’t capture specific details. Generally, NAT firewalls are greater and similar to proxy firewalls as an intermediary between a group of computers.


Packet filter

A first report type of network is calls as a packet network. It inspects transferred packets between computers. There are three basic actions regarding the packet consist of a silent discard and forward. Generally, around 21st century The bulk of internet communication used either transmission control protocol (TCP) or User datagram protocol (UDP). The first paper published on firewall technology in 1987. When engineers from Digital equipment corporation develops filter systems which is known as a packet filter firewall.


Connection tracking

From 1989-1990, Three colleagues from AT&T bell lab developed a second gen of firewalls calling them circuit-level gateways. Second gen firewalls perform the work of their first-gen predecessors. It also maintain knowledge of specific conversation between endpoints.


Application layer

Marcus ranum, wei Xu and peter churchyard released an application firewall which is known as a firewall toolkit in OCT 1993. This toolkit became the first base for gauntlet firewall at trusted info systems. The main key benefit of application layer filtering is that it can understand some applications and protocols FTP, DNS, HTTP. This allows it to identify unwanted using applications or services. As of 2012, the next gen firewall provides a wider range of inspection at the application layer.


Recent Articles

PS/2 Port
DVD Drive
Floppy Disk

Popular Articles



HK Sangani 34 Articles
I'm Harikrushna Sangani, a software engineer and the face behind IT Tutorials Cloud. I'm passionate about all things tech and love sharing my knowledge with you through easy-to-follow tutorials and tips. Join me on IT Tutorials Cloud to level up your coding skills and stay updated on the latest in the tech world. Let's learn together! Harikrushna Sangani