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What is a firewall?
A firewall, also known as a firewall or network firewall, is an important component of computer system security. It functions as a filter between your device and the network, ensuring security checks on all incoming and outgoing data. This term has its roots in the German language, where “Brandmauer” translates to “firewall,” and a similar word is used in English. Just as a fire wall protects buildings from fire, a firewall protects devices from external threats.
A firewall analyzes network traffic according to established rules and patterns. If it detects an unsafe connection, it blocks it. This can pertain to both the connection between your device and the internet, as well as interactions between two networks, such as a corporate network and the internet. It is important to note that firewalls can be both software-based and hardware-based.
Regular users often use built-in software firewalls that come with operating systems, which are sufficient for their needs. At the same time, corporate networks require more complex solutions, such as hardware-based firewalls, which are installed on servers or routers to quickly and effectively check large volumes of data.
Functions of a firewall
A firewall performs numerous functions aimed at ensuring the security of networks and personal computers. Here are the main threats it protects against:
- Computer viruses and worms: A firewall alerts users to suspicious files and can prevent their download.
- Data leaks: It monitors outgoing traffic, preventing the sending of passwords and other confidential information to attackers.
- DDoS attacks: A firewall analyzes traffic and blocks IP addresses from which attacks originate.
- Brute force attacks: It blocks connections that attempt to use programs for password guessing.
- Remote access hacking: A firewall prevents unauthorized connection attempts through system vulnerabilities.
- Phishing sites: It can block access to fraudulent websites that attempt to steal user data.
- Local network access control: Allows for the configuration of individual access rules for users and applications.
Types of firewalls
There are several types of firewalls that differ in methods of traffic filtering. Most modern solutions combine various types of filters. Here are the main types of firewalls:
- Packet filters: These filters check packet headers, including sender, recipient, and used ports.
- Stateful inspection: These firewalls monitor each connection session, providing a deeper level of protection.
- Application layer proxies: They analyze the contents of packets, blocking viruses and other threats.
- NGFW (next-generation firewall): This is a next-generation firewall that includes features for virus protection, spam blocking, and encrypted traffic analysis.
How to set up a firewall
Incorrect firewall configuration can lead to issues with internet access and the functioning of network applications. Here’s how to set up a firewall on various operating systems:
On Windows
- Open the Start menu and type “Firewall.”
- Click on “Windows Defender Firewall” to access the settings.
- In the “Advanced settings” section, create a new rule for a connection or application.
- If there are connection issues, allow the program to communicate through the network.
On MacOS
- Select the Apple menu and open “System Preferences.”
- Go to the “Privacy & Security” section.
- Click on “Firewall” to change its settings.
Proper firewall configuration is essential for ensuring the security of your device and protecting data. This is important for both regular users and companies that need to safeguard their networks from various cyber threats.