How Firewall Works

Firewall systems that control the network over special rules and certain protocols and make your systems safe against external dangers. By controlling the network you are in. It acts as a shield against outside behavior that threatens the network. Firewall working principles are based on the rules you have set. When security systems, acting within the framework of the rules. You have previously determined, detect a traffic that does not comply with the protocols you have determined.

They prevent access to the network and interrupt the flow of this traffic by creating a secure layer. In this way, it only allows the flow of allowed and rules-compliant network traffic. It provides an environment for the communication between your home or company internet and your network to be and remain at a secure level.

You can witness the use of Firewall almost everywhere in the face of developing and renewed technology. Any company or business, small or large. Uses Firewall services to protect its internet network and devices. These systems, which are prepared to protect your devices and information against cyber attacks, work with the logic of the White List.

The services, ports, processes and network traffic you include in this list allow you to use them securely. It blocks activities outside of this list as harmful. Instead of individually limiting users on your own network. You can easily do this through Firewall devices and save time.

What are Firewall Technologies?

Packet Filter (1st Generation)

The 1st generation internet security system, which was prepared in a very simple and practical way, was prepared in 1988 by Jeff Mogul from Digital Equipment Corporation. This system, which was prepared with a few small rules and protocols, spread rapidly and was used by companies and organizations. This simple system, prepared as a packet filter. Has developed over the years and has become more complex. AT&T’s Bill Cheswick and Steve Bellovin worked on the first generation firewall and developed it for their companies. Thanks to this filter, which was developed for the first time. Unwanted and harmful packets are prevented and the security of data flow and devices is ensured.

Circuit Level (2nd Generation)

With the development of technology, the first generation firewall has become inadequate. Between 1980 and 1990, the second generation firewall was developed at AT&T’s Bell labs with the work of Dave Presetto and Howard Trickey. Circuit-level firewalls, which have a more complex structure than the first generation firewall, are based on controlling network traffic and creating a secure internet service. In this way, it controls the incoming network traffic on the network and determines which packets are safe and which packets should be allowed.

Application Level (3rd Generation)

Third-generation firewalls, defined by publications by Gene Spafford, Bill Cheswick, and Marcus Ranum, are known as application-level firewalls or Proxy-based firewalls. These systems, which operate at OSI layers, determine which sites are safe and which network traffic should be allowed by allowing proxy settings on the internet. The first third generation Firewall, released as SEAL Product, takes the security level to the next level by providing better filtering service. In this way, the security of network systems and devices against new generation attacks is ensured.

Next Generation Firewalls

The first systems with a colorful and visual interface were developed by Bob Braden and Annette DeSchon in 1992 as a fourth generation packet filtering service. In 1994, an Israeli company known as CPST takes this service one level further and launches it. This service, known as Firewall-1, ensures the protection of personal data and devices by controlling all permissions on the network. Firewalls developed after this recipe are called fourth, fifth and next generation firewalls. Next-generation firewalls, powered by a security engine called Deep Packet Control and combining technologies known as IPS, are now more powerful and secure. At this point, firewall devices known as UTM (Unified Threat Management) emerge.

Next Generation Firewalls (NGFW)

The new generation firewalls, which combine integrated security systems (DLP, IPS, IDS, Content filtering, AV Control) in a single structure, draw attention with their “Identity Control” feature. Even if the IP address of a user on the system changes, it makes it possible to access the network with authentication technology and given authorizations. Thus, it is possible to control users and adapt to new generation network technologies. New generation firewall systems, which control applications and devices running on a port, help you create a secure layer by controlling all kinds of network protocols.

What are Firewall Types?

It is possible to divide the firewall systems, which are prepared to ensure the security of companies and institutions and to protect them against cyber attacks, into two classes. They are classified according to their structure and according to their architecture. Firewall systems, which are prepared according to their structures, appear in software and hardware. Systems prepared according to its architecture are; Static Packet Filter Firewalls are Circuit Level Firewalls, Dynamic Packet (Stateful) Filter Firewalls, Proxy Supported Firewalls and Hybrid (Hybrid) Firewalls.

Systems According to Their Structures

Software Firewall Systems

Software firewall systems, which can easily work on any computer, control the data flow to the computer and ensure that this flow is secure. These systems, which have a very low cost, are also extremely simple in terms of installation and use. These systems, which are suitable for use in places with a small number of computer networks, run on the operating system. So they put more load on the server. Also, they can pose security risks. When controlled by users as they are easy to disable.

Hardware Firewall Systems

It allows you to control the inputs and outputs of the network using the packet filtering method. They analyze and manage inbound and outbound traffic, creating a bridge between the network and the internet. Since they are not installed on the operating system or server. They do not affect performance and server speed. Ideal for businesses using large-scale networks. It is more secure than software firewalls.

Systems by Architecture

Static Packet Filter Firewalls

These systems, which work by reading and analyzing the header part of the data flowing in the traffic in the network. Have a structure that allows the passage of packets according to the permissions you create on the network. They allow or prevent the entry of incoming data as a result of analyzes such as the source address, destination address, port it wants to access and the protocol it will use. These systems, which work at the network layer in the OSI model, are still among the preferred systems, although they are obsolete. The biggest disadvantage is that the first sender system is sometimes undetectable.

Circuit Level Firewalls

They restrict access by hiding the IP address of the gateway system in the local network from outside sources. In this way, they have a flexible structure. They show a high level of performance because it examines packages on an extremely small scale. However, these systems. Which do not establish a direct connection between the source and the destination. Cannot analyze the packets between the source and the destination.

Dynamic Packet (Stateful) Filter Firewalls

These systems, which enable the tracking of data from source to destination, have been developed for situations where static packet filter firewalls are insufficient. Controlling many different layers from the header of the packet to its contents, these firewalls help to obtain more information about incoming and outgoing packets. These systems, which keep all ports closed circuit. Only open that port for use when authorized.

Proxy Supported Firewalls

When the source system sends a login request. This system sends that request to the firewall and the firewall forwards it to the source. This process continues even after logging in, thus creating an advanced firewall measure. These systems, which provide an isolation task between the target and the source. keep the network security at the highest level. They can directly check the package contents.

Hybrid (Hybrid) Firewalls

Firewall systems that host two or more of the above architectures at the same time. It acts as a shield that prevents cyber attacks and malicious software that can come to devices. Such as computers, servers, tablets or phones and your network over the internet. It has an extremely secure architecture as it works with different protocols and rules. These systems, which act as a bridge between the source and the destination. Prevent any harmful input by controlling the data flow.