What is a firewall and how does it work?

A firewall is software or service that is designed to protect a computer from unauthorized access, such as hackers and the sending of harmful information to the outside world. A firewall filters outgoing and incoming data to a computer via the Internet or another computer.

The term: “wall firewall” originally came from nomenclature related to car construction. Firewall there meant the physical separation of the engine from the passengers. This well captures the essence of the issue in IT as well: a firewall is a wall, that separates users from the threats lurking on the Internet.

How does the firewall work?

Every computer connected to a network, uses ports to connect to other devices. They are a kind of hole in the network that can make it easy for others to hack and lose data. Hackers operate in such a way that they search for bugs and vulnerabilities in software codes. The essence of a firewall is to check data transmission and, if a threat is detected, block access. The firewall also blocks bots-type programs that attack the IP address and other unused ports. There are two types of firewalls:

• Networked – works through software. Features easy installation and management.
• hardware – modem or router, connected to computer.

What else does firewall detect?

The firewall allows or rejects packets based on rules such as protocol, sender address, receiver address, source port, destination port, time, etc. In this way, the network is protected. The firewall also blocks the computer from the influx of Trojans, which are codes hidden in programs that can give signs such as suspending the operating system, displaying suspicious messages or deleting files. However, a firewall is not a full protection against viruses, but a supplement to an antivirus program.

Types of firewalls

• Filtering firewalls – monitor incoming network packets and allow flow only those that conform to defined rules. The most common filtering method on Linux is iptables (a command used to set filtering rules and change packets).
• NAT – network address translation, or making the IP address of an internal host to hide it from external monitoring. Otherwise known as IP address masking.
• Intermediary firewalls (proxies) – create a separate connection between the user and the firewall, and only from there the user connects to the server. In short: htto session is not immediately launched directly to the remote www server, but along the way the user waits for a connection to the Proxy. The firewall proxy catches various dangerous sites (e.g. pornographic, with vulgar words, etc.).

Some safety rules
on the web

1. Install antivirus software and update virus signature database.

2. Installing a firewall and keeping it tight.

3. if you have a Windows operating system, it is a good idea to enable automatic updates.

4. Disable message preview options in email programs.

6. Establishing strong passwords.

7. check, whether Spyware (spyware) is installed on the computer.

8. Install only proven programs.

9. Reading browser messages.

10. Informed consent (or not) for data processing.

Firewall at ITH

At ITH, the security of customer data is our top priority. We offer network protection, auditing and monitoring, we have a cloud firewall, VPN and stable, high-speed hosting. We encourage you to use the services of our specialists.