What Is a Firewall?

A firewall is a type of security software that guards your computer and data from hackers and other dangers. It examines incoming and outgoing traffic using a set of criteria to detect and then allow or prohibit safe traffic. These guidelines are based on previously defined security regulations inside an organization. In both personal devices and corporate networks, firewalls are employed.

Firewalls are similar to bouncers or doormen in that they stand at the doorways of business networks, applications, databases, and other resources, inspecting incoming (and outgoing) data traffic and choosing what should be let through and what should be denied.

However, the phrase “firewall” is just too wide for IT security customers to be useful. There are several types of firewalls, each of which protects various sorts of resources in different ways, both within data centers and corporate perimeters, as well as outside in the cloud.

In this article, we will focus on how firewalls work and how many different types of firewalls are out there.

How does a Firewall Work?    

Firewalls check various data packets for potentially hazardous material, such as malicious code, that has been identified as a known or established threat. If a data packet is detected as a system risk, the firewall prevents it from accessing the network and, as a result, from gaining access to your machine and inflicting harm.

Firewalls are either hardware or software barriers that separate your network from the internet or areas of your network from the rest of your system. Firewalls not only keep dangerous software out of your network, but some can also prevent an attacker from utilizing your system to spread harmful code since they can inspect data as it comes in and goes out.

What are Types of Firewalls?        

Depending on their construction, firewalls can be classified as software, hardware, or both. The functionality of each type of firewall varies, but the goal is the same. To obtain optimal protection, it is ideal to have both.

A hardware firewall connects a computer network to a gateway through a physical device. A broadband router, for instance. The term “appliance firewall” is used to describe a hardware firewall. A software firewall, on the other hand, is a straightforward application that works with port numbers and other installed software to protect a computer. A Host Firewall is a sort of firewall similar to this one.

Furthermore, depending on their features and security level, there are many different types of firewalls.

Furthermore, based on their features and the degree of protection they provide, there are a variety of additional types of firewalls. Firewall approaches that can be implemented as software or hardware include the following:

1. Stateful Inspection Firewall

A stateful inspection firewall, sometimes known as a “conventional” firewall, permits or blocks traffic based on state, port, and protocol. It keeps track of all activities from the time a link is established until it is terminated. Filtering choices are based on both administrator-defined criteria and context, which refers to utilizing data from prior connections and packets from the same connection.

The ACL’s ( Access Control List) extensive lines of configuration can be replaced by a stateful firewall, which can keep track of the state of every connection passing through it. In terms of operation, traffic that must pass through a firewall is first compared to a firewall rules list (is the packet authorized in the first place?). The stateful component of the procedure begins if the packet type is accepted through the firewall.

2. Unified Threat Management (UTM) Firewall

Originally known as unified threat management (UTM), Next-Generation Firewall (NGFW) capabilities deliver many security features and services in a single network device or service, safeguarding users from security threats in a simpler manner.

Antivirus, anti-spyware, anti-spam, network firewalling, intrusion detection and prevention, content filtering, and leak protection are often included in a UTM device. Remote routing, network address translation (NAT), and virtual private network (VPN) capabilities are also available from some devices. The solution’s appeal stems from its simplicity; enterprises that previously had different suppliers or appliances for each security activity can now consolidate them all under one vendor umbrella, backed by a single IT team or segment, and controlled through a single interface.

3. Next-generation Firewall (NGFW)      

A next-generation firewall (NGFW) extends the capabilities of a stateful network firewall, a technology pioneered by Check Point Software Technologies in 1994. A stateful firewall is a network security device that filters incoming and outgoing network traffic based on IP port and IP address combinations. New connection requests can be connected with existing genuine connections by intelligently examining the payload of particular packets. Application control, integrated intrusion prevention (IPS), and typically more sophisticated threat prevention capabilities like sandboxing are all included in a next-generation firewall.

In today’s NGFW arena Zenarmor is one of the best of them.

Better packet intelligence equates to more informed decision-making. Better decision-making leads to greater success in identifying and preventing cyber-attacks.

ZENARMOR’s technology drives the first packet inspection engine with native TLS inspection in the industry.

For each form of traffic, ZENARMOR technology also delivers high-visibility packet categorization and fine-grained policy enforcement.

Sunny Valley Networks has developed excellent packet intelligence so that any individual, educational institution, corporation, or enterprise may benefit from superior cyber protection.

Lightweight, appliance-free technology provides enterprise security features including:

  • L2-L7 Packet Filtering
  • Advanced Network Analytics
  • Application Control
  • User/Device-based Filtering
  • Policy-based Filtering and QoS
  • Web Filtering and Security
  • DNS Security
  • Built-in Full TLS Inspection (coming soon)

4. Virtual Firewall

In a virtualized environment, a virtual firewall is a firewall device or service that offers network traffic filtering and monitoring for virtual machines (VMs). A virtual firewall, like a typical network firewall, inspects packets and applies security policy rules to prevent unauthorized connections between VMs. In most cases, a virtual firewall is installed as software.

Virtual firewalls are often used to secure virtualized environments because they are the cheapest and most portable, thanks to the simplicity with which they can be moved from cloud to cloud. It’s also simple to upgrade and manage a virtual firewall.

Who Invented Firewalls?

Since the days of packet filtering, the modest firewall has gone a long way. Digital Equipment Corporation (DEC) was the first to design firewalls in the late 1980s.

These early firewalls generally worked on the first four levels of the Open Systems Interconnection (OSI) paradigm, intercepting traffic on the wire and examining the attributes of each individual packet to see if they fit a set of rules that had been established (source and destination address and port numbers, for example). These packets would subsequently be discarded or forwarded, depending on the situation.

This technique of traffic inspection, while quick, was quickly shown to be needlessly resource-intensive, prompting Check Point Software Technologies to introduce circuit-level firewalls, subsequently known as “stateful” firewalls.

Although layer 7 firewalling was again pioneered by DEC, with SEAL the first firewall “product” in 1991, application-level firewalls made a significant step forward with the introduction of the first open-source firewall, Firewall Toolkit (FWTK) by Trusted Information Systems in 1993.

The “classic” stateful inspection firewall was the industry norm for nearly a decade. While the UTM found a place in some situations until Palo Alto Networks defined the “next-generation firewall,” which acquired considerable market momentum in 2010 and beyond, the stateful inspection firewall was the dominating technology in the enterprise.