What Is a Firewall? Types of Firewall

What does a firewall do? Firewalls are important not only for their threat prevention capabilities but also the ways in which they enhance privacy and monitor traffic. In the context of this firewall meaning, firewalls provide several benefits.

Firewalls are able to send alerts about malicious data in addition to stopping the attacks. This enables administrators to see the frequency of attacks and take note of attack patterns.

Firewalls provide visibility into when and how threats attempt to penetrate your network. In addition, they prevent attacks from gaining a foothold in your system.

Firewalls can inspect the traffic generated by users as they try to access content linked to in a phishing attack. This is one of the key benefits of firewall technology. In this way, a firewall in a computer can protect well-meaning users from hurting their own devices or networks.

Firewalls, particularly when used to prevent data theft, can enhance the privacy of a network. Also, when firewalls are used to set up VPNs, they can ensure private communications between users.

A firewall consists of hardware and software that combine to protect a section of a network from unwanted data. A hardware firewall runs software installed inside it, and software firewalls use your computer as the hardware device on which to run. Whether you have your own firewall or a managed firewall run by a Firewall-as-a-Service (FWaaS) vendor, components will be similar.

The hardware of a firewall has its own processor or device that runs the software capabilities of the firewall. The software of a firewall consists of various technologies that apply security controls to the data trying to go through the firewall. Some of these technologies include:

1. Real-time monitoring, which checks the traffic as it enters the firewall
2. Internet Protocol (IP) packet filters, which examine data packets to see if they have the potential to contain threats
3. Proxy servers, which serve as a barrier between your computer or network and the internet. Requests you send go to the proxy server first, which forwards your web request on. A proxy server can control which websites users interact with, refusing to forward requests to sites that may pose a threat.
4. VPN, which is a type of proxy server that encrypts data sent from someone behind the firewall and forward it to someone else
5. Network Address Translation (NAT) changes the destination or source addresses of IP packets as they pass through the firewall. This way, multiple hosts can connect to the internet using the same IP address.
6. Socket Secure (SOCKS) server that routes traffic to the server on the client’s behalf. This enables the inspection of the client’s traffic.
7. Mail relay services, which takes email from one server and delivers it to another server. This makes it possible to inspect email messages for threats.
8. Split Domain Name System (DNS), which allows you to dedicate internal usage of your network to one DNS and external usage to another. The firewall can then monitor the traffic going to each server individually.
9. Logging, which keeps an ongoing log of activity. This can be reviewed later to ascertain when and how threats tried to access the network or malicious data within the network attempted to get out.

There are several different types of firewalls, and each one protects your network in a different way.

1. Packet layer: A packet layer analyzes traffic in the transport protocol layer. At the transport protocol layer, applications can communicate with each other using specific protocols: Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). The firewall examines the data packets at this layer, looking for malicious code that can infect your network or device. If a data packet is identified as a potential threat, the firewall gets rid of it.
2. Circuit level: A firewall at the circuit level is positioned as a layer between the transport layer and the application layer of the TCP/Internet Protocol (TCP/IP) stack. Thus, they work at the session layer of the Open Systems Interconnection (OSI) model. In the TCP model, before information can be passed from one cyber entity to another, there needs to be a handshake. A circuit level firewall examines the data that passes during this handshake. The information in the data packets can alert a firewall to potentially harmful data, and the firewall can then discard it before it infects another computer or system.
3. Application layer: An application layer firewall makes sure that only valid data exists at the application level before allowing it to pass through. This is accomplished through a set of application-specific policies that allow or block communications being sent to the application or those the application sends out.
4. Proxy server: A proxy server captures and examines all information going into or coming out of a network. A proxy server acts like a separate computer between your device and the internet. It has its own IP address that your computer connects to. As information comes in or goes out of the proxy server, it is filtered, and harmful data is caught and discarded.
5. Software firewalls: The most common kind of software firewall can be found on most personal computers. It works by inspecting data packets that flow to and from your device. The information in the data packets is compared against a list of threat signatures. If a data packet matches the profile of a known threat, it is discarded.

The most critical risks you expose your organization to by not having a firewall include:

1. Allowing open access to any intruder who wants to connect with your network and initiate an attack.
2. Losing sensitive data to attackers who break into your network and steal it from your servers or computers.
3. Your network crashing due to attackers infiltrating it with malware that brings down the systems and software needed to keep your network operational.

Here are some basic steps you can take to enhance your firewall security:

1. Use antivirus protection in addition to firewalls so you can stop a wider range of threats.
2. Limit the number of users who have rights to access sensitive areas of your network.
3. Constantly update your firewalls. In this way, you ensure that you’re protected from the most recent threats.
4. Back up business-critical data frequently so if an attack is successful you can use a backup to get important systems running again.
5. Segment your network with firewalls. Putting a firewall between different portions of your network can stop malware that tries to move laterally from one network segment to another.

The Fortinet line of FortiGate next-generation firewalls (NGFWs) combine the functionality of traditional firewalls with deep packet inspection (DPI) and machine learning to bring enhanced protection to your network. In this way, FortiGate can identify malware, attacks by hackers, and many other threats and block them. 

FortiGate also provides secure sockets layer (SSL) inspection, so even encrypted traffic is examined and filtered. FortiGate has paths allowing for future updates that incorporate the latest information from the threat landscape.

Download the 2021 Gartner Magic Quadrant for Network Firewalls where Fortinet was recognized for the 12th time in the Magic Quadrant.  

A firewall is a device that filters the traffic that is allowed to go to or from a section of your network. Also, within this firewall definition, a firewall can be used to set up a secure virtual private network (VPN) by encrypting the data that gets transmitted between the parties connected to it.

Firewalls are important not only for their threat prevention capabilities but also the ways in which they enhance privacy and monitor traffic. In the context of this firewall meaning, firewalls provide several benefits.

Firewalls work by inspecting packets of data and checking them for threats to enhance network security. They can check the contents of the data, the ports it uses to travel, and its origin to see if it poses a danger.

A firewall consists of hardware and software that combine to protect a section of a network from unwanted data. A hardware firewall runs software installed inside it, and software firewalls use your computer as the hardware device on which to run.