Firewall – Know about a System that Protects your Network & PC | #linux | #linuxsecurity


Internet and electronic devices are common in the modern days as we use them in our day-to-day life. We have internet networks and devices like PC or laptops in our homes and offices. It is important to protect those things from various viruses and from Hackers to keep them safe as our valuable and confidential data is stored there. We need a protected network and device to prevent any data loss or damage.

We all know the threat of cybercrime and firewall is one of the key elements that provide us the cyber security we seek for our network and IoT devices. It is an important tool which plays a very major role to secure our whole technical system.

So, it is a very positive thing to know about the different aspects of the firewall to get some specific idea of firewall and the importance of it to operate it in the most suitable way to protect your data.

What is a Firewall?

In simple words, a firewall is a kind of wall that protects your devices and networks from unwanted intruders to provide them security. All the unauthorized access to your network or device will get a denial from it and verifies the traffic before permitting them to pass. It is a firmware or software that stays between the online world and your private network and devices to secure them from many threats through the World Wide Web. Any kind of incoming and outgoing data is monitored by a firewall to block the dangerous one and opens the requested port for the safer one.

As it is one of the key components for the security of your network and device, generally you can find a built-in firewall in every PC or laptop and even in smartphones or many good routers. We connect our devices to different networks or routers so a firewall is a must thing for every device to give them security. And it should be updated with the latest security updates or patches to cover the loopholes in it or to enhance the quality of protection.

 

Why do we need a firewall?

The main functionality of a firewall is to protect your home or office network and the devices that are connected to the network for accessing the internet. A firewall is not a new thing to the technical world as the implementation of a firewall is old enough for security reasons. And today we have a modern and updated firewall to protect us from modern threats from the internet. The barrier of firewall prevents malware, spyware to save our device and network from getting corrupted or hacked.

Without a firewall or a turned-off firewall from your device or network security will be very dangerous as it can get infected with such viruses and any hacker can hack your whole system at any time. We connect our devices most of the time with the internet so it is recommended to use a firewall for the protection we get from it when we surf or connect with the net. Along with an updated antivirus, the firewall is also very important because it can filter traffic and control it for the safety of the devices and network. It is the best thing to check incoming and outgoing data to prevent attacks.

 

How does a firewall work?

The firewall follows the instructions of some pre-determined rules that are established to analyze and detect the threats from data packets and prevent them by blocking them. It only allows the data packets that are safe and opens up the port to permit the data to reach its destination. It secures our connection of the devices with the internet world by reviewing the incoming and outgoing traffic and preventing any sort of unprotected data to harm the system.

It is kind of the main door of your house with a trusted security guard with some specific instructions you provided him to allow or deny any person from getting inside your house. Based on those instructions, he can judge any person whether the person should be allowed or not. A firewall is also working like that with pre-installed rules to clear the way of any data packet after checking its safety.

If the data packet is safe then it will be allowed to get it and if the data packet is not safe then it will be blocked. A data packet is nothing but a piece of information containing data that provide some essential things like the content of the data and the destination or the source of it etc to evaluate the safety of it based on the rule sets. And firewall works to manage the safety and security of your network or device.

 

How many types of firewalls are there?

Different types of firewalls are used by different individuals or organizations for better security purposes depending on the size of the system and data filtering methods.

Firstly, take a look at the firewalls that we can by the size of the system they want to protect.

1. Network-based firewall

It is a type of firewall that is usually used for protecting a larger network in companies or organizations where multiple devices with data are connected with the same network. It protects the entire networking system like computers and servers to transfer traffic safely with other systems outside of this network. Generally, these types of network firewalls are hardware.

2. Host-based firewall

Compared to the network-based firewall, it is used for the protection of a single device which secures the device from potential threats. These devices are called hosts. So, it is covering a smaller network or an individual device. This is generally software that is installed in a device to manage traffic by inspecting them. For example- Windows in-built firewall.

Now, take a look at the firewalls that are based on the filtering of data.

Packet-filtering firewalls

For the control of data packets, a packet-filtering firewall is used with different rules or sets of rules. It monitors every incoming and outgoing data to allow them or block them according to the rules. It can block a port number or IP address etc. As the firewall provides some simple protections so it is not very advanced and limitations prevent it to deliver high security.

Stateful inspection firewalls

This is an advanced firewall compared to packet-filtering firewalls as it works based on stateful inspection and the established connections are also being tracked by it. It has a dynamic packet filter. Depending on the port, state, rules, etc it filters the traffic. These kinds of firewalls are majorly used for the inspection of internal traffic and for monitoring the data. It is good for the protection of your network but it is better to have additional antivirus to protect your device better.

Proxy firewalls

It is a more complex type of firewall that protects your network or device more effectively. A deep packet inspection is exercised by this firewall to check the data packets. Along with the sender and receiver, the content of the data packets is also being checked and analyzed with a proxy firewall. It will not allow any data to pass until the checking is finished and signals positive to go through.

Next-generation firewalls (NGFW)

Next-generation firewalls consist of some additional features to increase safety more convincingly. They are more advanced and upgrade the security to a different level if you compare them with previous firewalls. These can be, for example, so-called “Intrusion Detention System” (IDS) or “Intrusion Prevention System” (IPS). In addition, many secure connections are created over a Virtual Private Network (VPN). The firewall then controls the data packets before they arrive at the recipient from the VPN tunnel.

Where can we find a firewall?

For the users of Windows 7 and later, the firewall will be already there for using it to protect your device as windows defender includes its firewall with it. Apart from that, you can get a firewall from virus protection software. The installed firewall e.g. from Avira in your PC can be known as “Desktop firewall” or “Personal firewall”. Even your router could consist of a firewall of its own to protect the Wi-Fi network from online threats.

Windows computer: Where firewall can be found?

  • People who are using windows PC can go to the Control Panel.
  • After that, click on System and Security.
  • Here you can see Windows Firewall. Activate it if it is disabled.

Mac computer: Where firewall can be found?

  • Hop into settings.
  • Navigate to Security from there.
  • Then click on the Firewall tab. It must be activated.

Is Windows Defender a firewall?

It is an in-build and free security solution for Windows from Microsoft. It is not just a firewall. The security system has a firewall in it and provides antivirus services to the users. It is widely accepted among users and delivers some effective protection to prevent threats and viruses from online.

What happens if I turn off my firewall?

In order to install new virus protection programs or to test some programs, it may be necessary to disable the onboard firewall of Windows or Mac computers.

But always remember: if you turn off the firewall, you are not protected from harmful intruders during this time. Therefore, you should never turn off your firewall permanently, or only if a third-party firewall is replacing your Apple or Windows firewall.

With Windows 10 you deactivate the Defender Firewall via Start> Settings> Update and Security> Windows Security. Select Microsoft Defender Firewall under “Settings” and click “Off”.

With a Mac, go to System Preferences, then to “Security”. Click on the “Firewall” tab and unlock the area by clicking the lock symbol. You can then switch the firewall on or off.

With Linux, disable the firewall by entering the following command:

#For RHEL, CentOS, and other RPM-based 

To stop and disable

sudo systemctl stop firewalld
sudo systemctl disable firewalld

To Check status 

sudo systemctl status firewalld

Whereas to start and enable again:

sudo systemctl start firewalld
sudo systemctl enable firewalld

#For Ubuntu or Debian based systems:

sudo systemctl stop ufw
sudo systemctl disable ufw

To Check status

sudo systemctl status ufw

To start and enable again:

sudo systemctl start ufw
sudo systemctl enable ufw

 

Enable ports in the firewall – This is how you give targeted access to your network

Any computer consists of a certain number of ports. Ports are the possible accesses to a computer network. Between the client and the server, a connection is established through a port. After establishing the connection, data packets can be sent back and forth Ports are numbered from 0 to 65,536. These types of ports help you to surf the internet or send an e-mail. Some specific ports are reserved to do that type of work. Typically released ports like 993, 995, 80, or 443 enable to send an e-mail or surf the internet. Only port 0 is not for any use as it indicates no ports.

Conclusion

The use of a firewall is a must as we use multiple devices and networks to connect with the internet for many purposes. So, use an updated and activated firewall, and also in any virus protection program, you can activate the firewall as well. Check for any firewall in your router to use it if there is any. Online is a risky platform and you should be careful and protective of your data and network or devices.

The technology and security methods are always changing and upgrading so, you must go with the flow to maintain the advanced security systems and methods. That can protect you better than the old methods and systems.

 



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