Examining network devices for settings and configurations is an example of
Firewalls have existed since the late 1980’s and started out as packet filters, which were networks set up to examine packets, or bytes, transferred between computers. Though packet filtering firewalls are still in use today, firewalls have come a long way as technology has developed throughout the decades. Show
Back in 1993, Check Point CEO Gil Shwed introduced the first stateful inspection firewall, FireWall-1. Fast forward twenty-seven years, and a firewall is still an organization’s first line of defense against cyber attacks. Today’s firewalls, including Next Generation Firewalls and Network Firewalls support a wide variety of functions and capabilities with built-in features, including: Choosing the correct type of firewall to protect your network is a vital security decision. Going with the wrong type is worse than having no firewall at all since you get a false sense of security despite the network being wide open to an attack. So, what are the different types of firewalls you can deploy? And, more importantly, which one is the right option for your use case? This article presents eight different types of firewalls that keep malicious traffic out of networks. We analyze the pros and cons of each solution, explain what OSI layer(s) they operate on, and offer tips for choosing a firewall that best meets your security requirements. What is a Firewall?A firewall is a security device or program that monitors network traffic and detects potential threats. The main purpose of a firewall is to act as a barrier that allows non-threatening traffic in and keeps dangerous traffic out. The scope of a firewall's protection varies between use cases. Security teams use firewalls to:
Firewalls are one of the bases of network security in the client-server model. These systems ensure both incoming and outgoing traffic is safe, but they are vulnerable to:
While firewalls are a cybersecurity must-have, you require other mechanisms to remove threats reliably. Consider upgrading your firewall strategy with intrusion detection systems (IDSes), DDoS protection, and session monitoring. How Does a Firewall Work?Teams set up a firewall inline across a network to act as a border between external sources and the guarded system. Admins create so-called choke points at which a firewall inspects all data packets entering and leaving the network. A packet is a piece of data formatted for Internet transfer that contains:
Firewalls analyze packets based on pre-set rules to distinguish between benign and malicious traffic. These rulesets dictate how the firewall inspects the following:
The firewall blocks all packets that do not abide by the rules and routes safe packets to the intended recipient. There are two options when a firewall prevents traffic from entering a network:
Both options keep dangerous traffic out of the network, so choose the one that makes more sense from a security standpoint. Typically, security teams prefer to drop requests silently to limit the info in case a would-be hacker is testing the firewall for potential vulnerabilities. Types of Firewalls Based on Delivery MethodThere are three types of firewalls based on how you decide to deploy them: hardware, software, and cloud-based firewalls. Let's see what each of these strategies offers. Software FirewallsA software firewall (or a host firewall) installs directly on the host device. This type of firewall protects only one machine (network endpoint, PC, laptop, server, etc.), so admins must install a version of the software on each device they want to protect. Since admins attach a software firewall to a specific device, there's no avoiding some resource usage. These firewalls inevitably eat up some system RAM and CPU, which is a deal-breaker for some use cases. Pros of software firewalls:
Cons of software firewalls:
Hardware FirewallsA hardware firewall (or an appliance firewall) is a separate piece of hardware that filters traffic entering and coming out of a network. Unlike a software firewall, these self-contained devices have their own resources and do not consume any CPU or RAM from host devices. For some SMBs, a hardware firewall is a bit of an overkill, and they might find more value in per-host software firewalls. Hardware firewalls are an excellent choice for larger organizations with several subnetworks containing multiple computers. Pros of hardware firewalls:
Cons of hardware firewalls:
Cloud-Based FirewallsMany providers offer cloud-based firewalls that they deliver on-demand over the Internet. These services are also known as Firewall-as-a-Service and run either as IaaS or PaaS. Since an MSP manages a cloud-based firewall, this option is excellent for:
Like hardware-based solutions, cloud firewalls excel at perimeter security, but you can also set up these systems on a per-host basis. Pros of cloud firewalls:
Cons of cloud firewalls:
There's no reason to pick one type of deployment and rely solely on that setup. For example, you could set up a hardware or cloud firewall at the network perimeter while also having software firewalls on high-value hosts. Types of Firewalls Based on Method of OperationBelow is an in-depth look at the five types of firewalls based on their function and OSI layer. You can deploy any of them as hardware, software, or in the cloud. Packet-Filtering FirewallsPacket-filtering firewalls act as a checkpoint at the network layer and compare each packet's header info to a set of pre-established criteria. These firewalls check the following header-based info:
These types of firewalls only analyze surface-level details and do not open the packet to examine its payload. A packet-filtering firewall examines each packet in a vacuum without considering existing traffic streams. Packet-filtering firewalls are ideal for small organizations that require a basic level of security against well-established threats. Pros of packet-filtering firewalls:
Cons of packet-filtering firewalls:
Circuit-Level GatewaysCircuit-level gateways operate at the session OSI layer and monitor TCP (Transmission Control Protocol) handshakes between local and remote hosts. This simplistic firewall type quickly approves or denies traffic without consuming a lot of resources. However, these systems do not inspect packets, so even malware-infected requests get access if there's a proper TCP handshake. Pros of circuit-level gateways:
Cons of circuit-level gateways:
Stateful Inspection FirewallsA stateful inspection firewall (or dynamic packet-filtering firewall) monitors incoming and outgoing packets at the network and transport layers. This firewall type combines packet inspection and TCP handshake verification. Stateful inspection firewalls maintain a table database that tracks all open connections and enables the system to check existing traffic streams. This database stores all key packet-related info, including:
When a new packet arrives, the firewall checks the table of valid connections. Familiar packets go through without further analysis, while the firewall evaluates non-matching traffic according to the pre-set ruleset. Pros of stateful inspection firewalls:
Cons of stateful inspection firewalls:
Proxy FirewallsA proxy firewall (or application-level gateway) serves as an intermediate between internal and external systems. These firewalls protect a network by masking client requests before sending them to the host. Proxy firewalls operate at the app layer, the highest level of the OSI model. These systems have deep packet inspection (DPI) capabilities that check both payloads and headers of incoming traffic. When a client sends a request to access a network, the message first goes to the proxy server. The firewall checks the following:
The proxy then masks the request and forwards the message to the web server. This process hides the client's ID. The server responds and sends the requested data to the proxy, after which the firewall passes the info to the original client. Proxy firewalls are the go-to option for businesses trying to secure a web application from malicious users. These systems are also popular when a use case requires network anonymity. Pros of proxy firewalls:
Cons of proxy firewalls:
Next-Generation FirewallsA next-generation firewall (NGFW) is a security device or program that combines several functions of other firewalls. Such a system offers:
Next-gen firewalls also include additional network security measures, such as:
NGFWs are a common choice in heavily regulated industries, such as healthcare or finance. Companies that must adhere to HIPAA and PCI are the usual adopters. Pros of next-generation firewalls:
Cons of next-generation firewalls:
Like with delivery models, nothing is stopping you from using multiple types of firewalls at the same time. Companies often set up several firewalls in the same network and deploy them at different levels. Which Firewall Type is Right for Your Business?No two businesses have the same assets, networks, and risk tolerance, so every company has unique firewall needs. The main questions to answer when choosing a firewall type are:
Answers to these questions help identify the right firewall option. Here are a few extra tips to help you out:
A smart strategy when choosing a firewall is to start by analyzing your weaknesses. Learn how to perform a network security audit that thoroughly examines the current state of your network. Understand What Different Types of Firewalls OfferA firewall is the first line of defense if someone or something tries to breach your company. These systems have the potential to make or break a security strategy, so treat their selection and setup accordingly. Know what different types of firewalls offer and how they keep assets safe before you go all-in on a solution. What are some examples of network security devices?Types of Network Security Devices. Firewalls. Firewalls are one of the most fundamental network security appliances. ... . Intrusion Protection Systems (IPS) ... . Unified Threat Management (UTM) ... . Network Access Control. ... . Email Security Gateways. ... . Web Application Firewalls (WAF) ... . VPN Gateways. ... . Network Device Backup and Recovery.. What are the 3 types of firewalls?Based on their method of operation, there are four different types of firewalls.. Packet Filtering Firewalls. Packet filtering firewalls are the oldest, most basic type of firewalls. ... . Circuit-Level Gateways. ... . Stateful Inspection Firewalls. ... . Application-Level Gateways (Proxy Firewalls). What is an example of firewall?A firewall that filters IP traffic between a pair of bridged interfaces. A firewall is a combination of various firewall types. For example, an application inspection firewall combines a stateful firewall with an application gateway firewall.
What is network security techniques?Network Security involves access control, virus and antivirus software, application security, network analytics, types of network-related security (endpoint, web, wireless), firewalls, VPN encryption and more.
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