Need to Know: What is a Firewall?

what is a firewall

What is a firewall?

A firewall is a security system for devices connected to a network. It protects the devices and data from outside attacks by restricting access to only those who are allowed in.

Most people do not know what a firewall is, but it is something that you should be very familiar with if you work on or own a computer.

In this article we will discuss exactly what firewalls are, how they work, and why they should be an integral part of your computers protection against viruses and other malware.

About firewalls

A firewall is a hardware or software program that controls the incoming and outgoing traffic for one system.

It can be placed on an individual computer, but it more often than not is used by companies to protect their network of computers from outside attacks. Firewalls are installed in routers which connect multiple devices together into a local area network (LAN).

How does a firewall work?

A firewall works by checking each packet of data that is sent or received.

The device calculates a number which represents the information in the packets header, and then adds it to an access control list (ACL). It only allows those with matching numbers through while blocking everything else. For this reason firewalls are considered stateful because they keep track of the state (the packets, their sequence number, and so on) of all connections between devices.

Firewalls also keep a record known as an event log that logs each packet that is allowed through or blocked.

The firewall can monitor this log to detect attacks and other suspicious activity in real time. Some firewalls can also take automatic action based on the information in the event log, such as blocking or disconnecting a user who has attacked your system.

What does a firewall do?

The main purpose of a firewall is to determine if the traffic that it receives should be blocked or allowed through.

It can also monitor existing connections for suspicious activity and block any attacks from continuing into your network.

A firewall provides protection against outside threats by blocking all unauthorized access attempts. It uses many types of security protocols and other methods to ensure that only the appropriate users can access your network.

Why is a firewall important?

Firewalls are important because they protect all of the devices that attach to your network.

Without a firewall you run the risk of allowing worms, viruses and other malware through which could lead to data loss or theft as well as damage to any connected hardware.

If you do not have an up-to-date firewall installed on your system you should consider getting one as soon as possible.

Deciding on a firewall

There are many different types of firewalls available, including free and commercial solutions.

The free firewalls available are usually not as good as the commercial options.

In general, for a small business you should look into purchasing an enterprise-level firewall designed specifically for that purpose and industry.

For home use there are also many free firewalls available such as Comodo Firewall or ZoneAlarm which work well to protect your system from outside threats.

There are a few main things you should consider when looking for the right firewall software:

  • Antivirus compatibility: many firewalls have an antivirus built in which is designed to work with other types of security in order to provide better protection, so make sure that it will be compatible with your existing virus protection. This is especially important if you are using an antivirus from a different company since they may not play well together.
  • Ease of use: even the most powerful firewalls available can be easy to install and set up for anyone who knows their way around computers, but some software is more user friendly than others so make sure it will suit your needs.
  • System requirements: make sure that your firewall will have the minimum system requirements to run properly on any of the devices you plan to install it on. Many firewalls require more resources than others, so if you are using an older computer or a laptop with limited memory then be careful when choosing which software is right for you.

The different types of firewalls and technologies explained.

There are many different types of firewalls available from free to enterprise-level, each with their own unique features and abilities.

A good place to start when choosing a firewall is determining what type you will need based on the devices that you plan to connect it to.

The main three categories of firewalls are hardware, software, and virtual.

A hardware firewall is a physical device that you connect to your network in order to protect it from outside threats on the internet.

Many of these devices can also be used as routers so they are able to provide protection for all of the different types of networks attached to them such as homes and businesses.

What is a network firewall?

A network firewall is a device that provides protection for devices connected to the same network or local area network.

It works by filtering out any traffic not intended for those devices and blocking it from entering, while allowing through only trusted people and information.

Comparing firewall to VPN, IDS/IPS and proxy.

Many people use VPNs to provide security and allow access through the firewall without being able to be detected.

This is done by encrypting all outgoing data so that it cannot be read while traveling across the network, this way only authorized users can access your system or files over a public connection such as an internet cafe or hotel Wi-Fi.

The downside to VPNs is that they can take up a lot of bandwidth and resources since they are essentially creating their own dedicated network in order to provide access, but for the most part it will be well worth it depending on your needs.

What are IDS/IPS proxies? How do they work?

An Intrusion Detection System or IDS is a system that will monitor the network for any possible intrusions and stop them before they can do damage.

IDS are used to protect systems from outside threats such as hackers trying to access your files, viruses attempting to install themselves on your computer without permission, and bots launched by malware meant to damage the system or steal information.

They can be used to monitor incoming and outgoing traffic for certain types of files, keywords, phrases, etc that would indicate an attack is being made in order to take action before any damage occurs.

IDS are usually installed on a computer acting as a server which will alert others when suspicious activity is detected.

An Intrusion Prevention System or IPS is a more advanced version of an IDS that can actually block any suspicious activity before it has the chance to do damage.

This type of system works by taking over your computer and allowing you complete control, this way no unauthorized changes are made without your knowledge while working on the machine.

IPS are usually installed on a dedicated server often referred to as an IPS sensor, they monitor incoming and outgoing traffic for certain types of files that could indicate someone is trying to attack your system or steal information.

They will then either block the activity outright so it never has a chance to happen in order to protect you from harm, or alert others that something is happening in order to have someone else come and deal with it.

The main difference between a firewall, IDS IPS proxies and VPNs are that firewalls provide protection for devices connected to the same network whereas an IDS IPS proxy works as a layer of defense over your entire system by protecting data from outside threats before they can ever have a chance to do damage, whereas VPNs are used to provide access without being detected and allow for data encryption.

What is the difference between an IDS IPS proxy and firewall?

A network firewall works by filtering out any traffic not intended for those devices and blocking it from entering while allowing through only trusted people and information in order to protect those devices from outside threats.

An IDS IPS proxy works as a layer of defense over your entire system by protecting data from outside threats which can be done through file monitoring or taking control in order to prevent any damage before it ever has the chance to happen often times alerting others if suspicious activity is detected.

Types of Firewalls

Packet-filtering firewalls

A Packet-filtering Firewall is what would be referred to as a traditional firewall, it works by filtering out any traffic not intended for those devices and blocking it from entering while allowing through only trusted people in order to protect those devices from outside threats.

Application layer and proxy firewalls

An Application Layer or Proxy Firewall is different in that these types of firewalls work by acting as a proxy, allowing only certain types and forms of traffic to pass through while filtering out any other data.

This type of firewall can see all the information passing over your network which allows for more granular control on what should be allowed in and out.

Static packet filtering firewall

A Static Packet Filtering Firewall works by filtering out certain files and connections based on their port numbers or other identifying factors such as the origin of a connection.

This type of firewall does not allow for any changes in its rules to be made, it is set up at installation which makes it less flexible than others but also more secure since it is unable to be changed by anyone.

Packet filtering is also a technology used for other firewalls. The main purpose of this technology is to allow or block packets based on their attributes.

A packet filter firewall is used by the software itself in order to control what type of traffic can pass through it and where that data should be allowed into your system from not only a security standpoint but also an efficiency one as well, limiting any unnecessary information flowing back and forth over your network which can slow it down or cause other problems.

Stateful inspection firewalls

A Stateful Inspection Firewall is more advanced than the previous types and works by inspecting all of a data packet’s information, they work by keeping track of any conversation that has happened between devices allowing for better control over what should be allowed in or out.

This type of firewall can often times block traffic based on many different factors such as the source or destination of a file.

Virtual firewall

A Virtual Firewall is not a physical piece of software that can be installed on your device, but rather it functions through an operating system’s kernel.

This type of firewall works by being able to create and manage virtual network devices which are often times connected to the same IP address as their actual hardware counterparts but work in a slightly different way.

Next generation firewalls (NGFW)

Next Generation Firewalls are the next step in firewall technology and work by allowing for better visibility into all of your network traffic which allows for increased control over what information should be allowed through.

The next generation firewall is a feature-rich software that can monitor and control network traffic at both the application layer as well as the data link.

These types of firewalls allow you to see every packet moving across your system, seeing everything that is going on it will provide greater protection against all types of threats and will allow you to see exactly where your vulnerabilities lie.

Unified threat management firewalls (UTM)

Unified Threat Management Firewalls are also a step up from traditional firewalls, they allow for the protection of your network by working to provide greater security and control over what information should be allowed in or out.

This type of firewall will not only protect devices on your network but it is able to do so much more than a traditional firewall, these types of firewalls allow for integration with numerous other technologies which can increase the protection and security of your system.

Firewall (computing)

A Firewall is a computer system which controls the incoming and outgoing network traffic by analyzing the data packets (also called “frames”) that are moving in or out of your device and allowing for only certain types to move through while blocking others.

Do you need a firewall at home?

A firewall at home is great to have to take extra precautions. If you work from home or run a business from home, this would make more sense to have.

However most would find an antivirus software on their personal computer more cost effective for every day use.

Are firewalls software-based or hardware-based?

Firewalls can be software-based or hardware-based.

A software-based firewall is usually virtualized on top of a hardware that is being used for another primary function.

Whereas a hardware-based firewall is designed to be used primarily for firewall purposes.

Many hardware devices are standard to be multi-purposed with firewalls.

What do firewalls protect against?

A firewall protects your device from threats which could come in the form of viruses, spam emails, or malware that would cause harm to any systems connected to it by blocking these types of files and attempts at communication with them when they are detected.

Key Points

  • Firewalls are a computer system which controls the incoming and outgoing network traffic by analyzing data packets that are moving in or out of your device.
  • Firewalls work to block only certain types while allowing others through.
  • A hardware firewall is being used primarily for firewall purposes, software-based firewalls can be virtualized on top of hardware where it functions as another primary function.

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