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Types of Firewalls


Are you looking for the best way to protect your business from possible threats?

When you know how firewalls work, you can figure out which is the best option for you. This article talks about the different types of firewalls, so you can make an informed choice.

What is a Firewall?

The simplest way to add a security layer between a system and malicious attacks is to set up a firewall. A firewall is a network traffic monitoring security device. It safeguards the internal network by filtering incoming and outgoing traffic according to a set of rules.

How does a Firewall Work?

To protect a system from malicious traffic, a firewall is installed on the hardware or software level. It can protect a single machine or an entire network of computers, depending on the configuration. The device inspects all incoming and outgoing traffic against a set of rules.

Requesting and transmitting data from a sender to a receiver is how you communicate over the Internet. Data is broken up into manageable data packets that make up the initially transmitted entity because it can’t be sent as a whole. A firewall’s job is to inspect data packets traveling to and from the host.

What exactly does a firewall look at? A header (control information) and payload make up each data packet (the actual data). The header contains details about the sender and receiver. The packet must first pass through the firewall before entering the internal network via the defined port. This transfer is determined by the data it contains and how it conforms to predetermined rules.

The firewall, for example, could have a rule that blocks traffic from a specific IP address. The firewall denies access to data packets with that IP address in the header. A firewall can also deny access to anyone other than the specified trusted sources. This security device can be configured in a variety of ways. The type of firewall determines how well it protects the system in question.

Types of Firewalls

Firewalls can have a wide range of operation methods and overall structure, even though they all serve to prevent unauthorized access. There are three types of firewalls based on their structure: software firewalls, hardware firewalls, or both. The remaining types of firewalls listed here are firewall techniques that can be implemented as software or hardware.

Software Firewalls

On the host device, a software firewall is installed. It must use its resources to work because it is attached to a specific device. As a result, it will inevitably consume some of the system’s RAM and CPU. As a result, a Host Firewall is another name for this type of firewall.

You must install the software on each device if you have more than one. It necessitates individual configuration for each because it must be compatible with the host. As a result, the most significant disadvantage is the time and expertise required to administer and manage firewalls for each device.

On the other hand, software firewalls have the advantage of being able to distinguish between programs while filtering incoming and outgoing traffic. As a result, they can block one program while allowing access to another.

Hardware Firewalls

As the name implies, hardware firewalls are security devices that sit between an internal and external network as a separate piece of hardware (the Internet). An Appliance Firewall is another name for this type of firewall.

Unlike a software firewall, a hardware firewall has its own resources and does not use the host devices’ CPU or RAM. It’s a physical device that acts as a gateway for traffic flowing into and out of a corporate network.

Medium and large businesses use them with multiple computers connected to a single network. In such cases, hardware firewalls are more practical than installing separate software on each device. Because configuring and managing a hardware firewall requires knowledge and skill, ensure that this task is delegated to a qualified team.

Packet Filtering Firewalls

The packet-filtering firewall is the most basic type of firewall when it comes to types of firewalls based on how they work. It connects to a router or switch and acts as an inline security checkpoint. It monitors network traffic by filtering incoming packets based on the information they contain, as the name implies.

Each data packet, as previously stated, consists of a header and the data it transmits. Based on the header information, this type of firewall determines whether a packet is allowed or denied access. It does so by looking at the protocol, the source IP address, the destination IP address, the source port, and the destination port. The packets are passed on or dropped depending on how the numbers match the access control list (rules defining wanted/unwanted traffic).

A data packet will not be allowed to reach the system if it does not comply with all of the required rules.

A packet-filtering firewall is a quick solution that doesn’t require much space. It is, however, not the safest option. It examines the header information but does not examine the data (payload). The packet-filtering firewall is not the best option for strong system security because malware can also be found in this data packet section.

Circuit-Level Gateways

Circuit-level gateways are a type of firewall that monitors TCP (Transmission Control Protocol) connections and sessions at the session layer of the OSI model. Their primary responsibility is to ensure the security of the established connections.

Circuit-level firewalls are usually integrated into software or an already installed firewall.

They, like pocket-filtering firewalls, inspect the information about the transaction rather than the data itself. Circuit-level gateways are also convenient, easy to set up, and don’t require a separate proxy server.

Stateful Inspection Firewalls

A stateful inspection firewall monitors the TCP 3-way handshake to keep track of the status of a connection. This allows it to keep track of the entire connection – from beginning to end – and only allow inbound traffic that is expected.

The stateful inspection creates a database (state table) and stores the connection information when starting a connection and requesting data. Each connection’s source IP, source port, destination IP, and destination port are recorded in the state table. It creates dynamic firewall rules to allow anticipated traffic using the stateful inspection method.

This type of firewall provides additional security. When compared to stateless filters, it enforces more checks and is safer. In contrast to stateless/packet filtering, stateful firewalls inspect the actual data transmitted across multiple packets rather than just the headers. As a result, they necessitate more system resources.

Proxy Firewalls

A proxy firewall is an intermediary device between internal and external systems communicating over the Internet. It secures a network by rerouting requests from the original client and passing them off as its own. Proxy means “to serve as a substitute,” which is precisely what it does. It takes the place of the client who is making the request.

When a client requests access to a web page, the proxy server intercepts the message. Pretending to be the client, the proxy sends the message to the webserver. The web server then responds by providing the requested information to the proxy, then forwarding it to the client. This conceals the client’s identity and location, shielding it from restrictions and potential attacks.

Next-Generation Firewalls

The next-generation firewall is a security device that combines the functions of several different firewalls into one device. Packet, stateful, and deep packet inspection are all included. Simply put, NGFW examines the packet’s actual payload rather than just the header information.

The next-generation firewall, unlike traditional firewalls, inspects the entire data transaction, including TCP handshakes, surface-level, and deep packet inspection.

NGFW provides adequate protection against malware, external threats, and intrusion. These devices are quite adaptable, and the functionalities they provide are not well defined. As a result, make sure to look into what each option offers.

Cloud Firewalls

A cloud firewall, also known as firewall-as-a-service (Faas), is a cloud-based network security solution. Third-party vendors, like other cloud solutions, maintain and run it over the Internet.

Clients frequently use cloud firewalls as proxy servers, but the configuration varies depending on demand. Their primary benefit is scalability. They are not reliant on physical resources, allowing the firewall capacity to be scaled according to traffic volume.

This solution is used by businesses to secure an internal network or other cloud infrastructures (Iaas/Paas).

The Best Firewall for Business

There is no need to be explicit when deciding which firewall to use. Multiple layers of protection are provided by using multiple firewall types.

Consider the following factors as well:

  • The size of the business. What is the size of the internal network? Do you need a firewall that monitors the internal network, or can you manage a firewall on each device? When deciding between software and hardware firewalls, these questions must be addressed. Furthermore, the ability of the tech team assigned to manage the setup will play a big role in deciding between the two.
  • The available resources. Is it possible to separate the firewall from the internal network by using a separate piece of hardware or even the cloud? The amount of traffic that the firewall must filter and whether or not it will be consistent are both important considerations.
  • The level of security that is required. The number and types of firewalls should correspond to the level of security needed by the internal network. A company that deals with sensitive client information should strengthen its firewall protection to keep data safe from hackers.

Create a firewall configuration that meets the requirements while considering these factors. Make use of the ability to layer multiple security devices and set up the internal network to filter any traffic. See how phoenixNAP ensures cloud data security for secure cloud options.

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