The new episode of the series I watched is out, the system that warns you when you want to go and watch it from a site with lots of betting ads; that friend who warns you when you download software that costs thousands of dollars for free; That companion firewall that tells you that your computer is under threat is your digital firewall. Most of the time, it is not given much importance by users, but firewall can really be a life saver.
In its most basic definition, firewall; It filters and blocks potential threats by controlling incoming and outgoing data on the network. This system is being developed day by day. Because malicious requests from some reliable sources often manage to pass the filter. That’s why everyone needs a good digital firewall. Let’s take a closer look at the questions like what is a firewall, what is it good for, what are the types.
What is a firewall?
The firewall, which we can also define as a digital firewall; It is a network security system that controls incoming and outgoing data packets to and from the network, based on software and hardware, within the framework of certain rules. Depending on the filter it uses while controlling the network, it always passes the internet traffic through controls such as IP filtering, port filtering, web filtering, content filtering.
Most operating systems today use their own software-based firewall system. At the same time, routers that transfer data between networks also have their own firewall systems. Although the widespread use of the Internet and computers is a fairly new situation, firewall security systems are a technology that emerged in the 1980s.
What does a firewall do?
Firewall network security systems, which work as hardware or software bases, examine incoming and outgoing data packets to the network with a predetermined filter. The main purpose is to prevent possible attacks by passing data packets from unsafe sources through this filter.
Firewall network security systems are located on ports where data is shared over the network with external devices. The description “Source address 172. 18. 1.1 is allowed to reach destination 172. 18. 2.1 over port 22. ” is the most accurate description of what these digital firewalls do.
How does Firewall work?
Let’s go through an example to understand how firewall network security systems work; Let’s think of IP addresses as houses and port numbers as rooms. Only secure people, that is, secure source addresses, can enter the house. People entering the house can only reach certain rooms, namely connection points, by passing through another filter. In other words, the firewall filter provides control and supervision at multiple points.
The old-style packet filtering firewall security network systems were a bit weak in this regard. They checked the data packets through a basic filter and sometimes accepted the request directly from the trusted source. As it became clear over time that not every request from a reliable source was in good faith, firewall network security systems were developed and different types emerged.
Firewall types:
- Next-generation firewalls
- Proxy firewalls
- Network address translation firewalls
- Stateful multilayer inspection firewalls
Next-generation firewalls:
Next-generation firewalls, NGFW for short, in Turkish, new generation firewalls; They support traditional filters with additional features such as encrypted traffic control, intrusion prevention systems, antivirus. The most important feature of these systems is deep packet inspection. Thanks to deep packet inspection, even requests from secure sources are treated with suspicion and in-depth inspection is made.
Proxy firewalls:
Proxy firewalls control application-level security. In other words, unlike the others, they act as a bridge between two systems. In this system, the client sends a request to the firewall, the request is filtered and the request is approved or blocked depending on the situation. It monitors traffic for layer protocols such as proxy, HTTP and FTP, filters and uses deep packet inspection.
Network address translation firewalls:
Network address translation firewalls, NAT for short, network address translation firewalls in Turkish; It keeps other IP addresses private by allowing devices with different network addresses to connect to the network via a single IP address. In this way, hackers who want to attack through their IP address will return empty-handed. NAT is likened to a Proxy system because it is a system located between a group of computers and an external network.
Stateful multilayer inspection firewalls:
Stateful multilayer inspection firewalls, shortly SMLI, in Turkish, stateful multilayer inspection firewalls; They examine and compare data packets in both the network transport and the application layers. As a result of comparison, only secure packets can pass the system. It’s primary purpose is to make sure the source is secure, as it does layer-by-layer filtering.
We answered questions such as what is the firewall that ensures our security at every step we take in the internet world, what it does, how it works, what are the types, and we talked about the important details you need to know about network security systems.
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