What Is a Host-Based Firewall? Ultimate Guide

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A host-based firewall is a type of firewall specifically designed to provide security to a single host, such as a computer or server, by monitoring and controlling its incoming and outgoing network traffic based on predetermined security rules.

This guide will dive into the technology behind host-based firewalls and explore how they work, how they differ from network firewalls, and their features, advantages, and disadvantages.

How host-based firewalls work

Host-based firewalls are designed to protect individual devices by closely monitoring and managing network traffic entering and leaving the device. They operate by examining network packets in real-time and making decisions on whether to permit or block traffic based on a predefined set of rules or policies. These rules take into consideration factors such as source and destination IP addresses, port numbers, protocols, and applications involved in the communication.

One key feature of host-based firewalls is their ability to control traffic at the application level. This granular control allows users to set rules specific to individual applications, giving them more control over the security of their devices. For example, a user may configure the firewall to only allow a certain web browser to access the internet while blocking other potentially unsafe applications.

Host-based firewalls often include additional security features, such as intrusion detection and prevention systems (IDS/IPS), which analyze network traffic for signs of malicious activity or policy violations. Some also offer advanced features like sandboxing, which isolates and analyzes suspicious files in a secure environment, and virtual private network (VPN) support, which secures data transmission between devices and networks.

Overall, host-based firewalls play a crucial role in securing individual devices, allowing for customized security settings tailored to the needs of the user or organization and providing an additional layer of protection alongside network-based firewalls and other security measures.

Host-based firewall vs. network firewall

Host-based firewalls and network-based firewalls serve similar purposes but have different areas of focus. While a host-based firewall resides on individual devices and is responsible for protecting that specific device, a network-based firewall, also known as a hardware firewall, is a separate device installed at the perimeter of a network.

Network-based firewalls protect multiple devices connected to the network by regulating incoming and outgoing traffic between the network and the internet.

The primary differences between these two types of firewalls include:

  • Deployment: Host-based firewalls are installed on each device within a network, whereas network firewalls are standalone devices that protect the entire network.
  • Scalability: As the number of devices in a network grows, the management and configuration of host-based firewalls can become complex. In contrast, network firewalls require fewer adjustments and can be more scalable.
  • Granularity: Host-based firewalls offer a more granular level of control, as they can be customized for each device. Network firewalls typically apply a standard set of rules across the entire network.
  • Cost: Host-based firewalls are often less expensive than network firewalls, especially for smaller networks or individual devices. However, the cost curve can ultimately surpass network firewalls the more host-based firewalls you have to buy.

What do host-based firewalls protect you from?

Host-based firewalls play a critical role in safeguarding individual devices against various types of cyber threats. By offering personalized and granular control over network traffic, they provide protection in several key areas: unauthorized access, malware, data breaches, and unwanted outgoing traffic.

Unauthorized access

Host-based firewalls can detect and block unauthorized attempts to access the device, such as brute-force attacks, port scans, or unauthorized remote login attempts. This helps prevent unauthorized users or malicious actors from gaining control over the device or accessing sensitive information stored on it.

Malware and virus infections

By controlling which applications and services can access the network, host-based firewalls can help prevent the spread of malware and viruses. For example, if a device is infected with malware that tries to connect to a command-and-control server or spread to other devices on the network, the firewall can block these connections, limiting the impact of the infection.

Data breaches and information theft

Host-based firewalls can prevent cyber criminals from exfiltrating sensitive data from a compromised device. By monitoring and controlling outgoing traffic, they can detect and block suspicious connections, such as those to known malicious domains or unusual data transfers.

Unwanted outgoing traffic

A host-based firewall can also identify and block unwanted outgoing traffic, which may be indicative of a compromised device. This could include connections to known botnet command-and-control servers or the unauthorized use of system resources for activities such as cryptocurrency mining or participating in distributed denial-of-service (DDoS) attacks.

4 examples of host-based firewalls

Each firewall offers unique features and capabilities, catering to specific needs and requirements, and ensuring a more secure and protected digital environment. Here are four popular host-based firewalls that showcase the variety of options available for users across different platforms.

Windows Firewall

A built-in firewall for Microsoft Windows operating systems, Windows Firewall provides essential protection against unauthorized network access. It offers inbound and outbound filtering rules, allowing users to create customized settings depending on their needs. While it may not have the advanced features offered by third-party firewalls, it is a reliable and user-friendly option for users seeking basic protection.


A popular third-party firewall for Windows, ZoneAlarm offers advanced features, such as application control and real-time threat monitoring. This firewall not only provides users with increased security options but also incorporates advanced threat detection and monitoring tools, which can identify and block potential threats before they compromise a system.

ZoneAlarm offers Free and Pro plans, with the Pro plan currently starting at $22.95 a year for one PC.

Little Snitch

A macOS host-based firewall, Little Snitch monitors and controls application-level network activity, offering enhanced visibility and control over incoming and outgoing connections. This firewall allows users to block or permit specific applications from connecting to the internet and provides real-time alerts when new connections are attempted, ensuring that users have the ultimate control over their network traffic.

Pricing for Little Snitch starts from $74.95 for a single license. It also offers a free trial.

UncomplicatedFirewall (UFW)

A user-friendly firewall for Linux systems, UFW simplifies the process of managing iptables, the built-in Linux firewall. With an easy-to-understand command-line interface, UFW makes it straightforward for users to create and manage firewall rules, ensuring their Linux systems are well-protected from potential threats.

Advantages of host-based firewalls

Host-based firewalls offer several benefits that contribute to an organization’s overall security strategy. They include:

  • Granular control: Host-based firewalls offer precise control over network traffic at the individual host level.
  • Protection against internal threats: They provide an additional layer of security against compromised devices or malicious insiders within the network.
  • Flexibility: They can be customized to suit the specific needs of each host, providing a tailored security solution.
  • Compatibility: They can be used alongside network firewalls for a comprehensive security strategy.

Disadvantages of host-based firewalls

Host-based firewalls are good for a variety of use cases, but they can’t do everything. Here are a few of their shortcomings:

  • Complexity: Managing individual firewalls on each host can be time-consuming and complex.
  • Resource consumption: Running a firewall on each host can consume system resources, potentially affecting performance.
  • Limited scope: Host-based firewalls only protect the host they are installed on, leaving other devices in the network potentially vulnerable.

Bottom line: Using host-based firewalls on your devices

Host-based firewalls provide an essential layer of security for individual devices and work well alongside network-based firewalls and other security measures. Implementing a host-based firewall helps ensure comprehensive protection for your devices and sensitive data, regardless of where you connect or what network you are using.

While they may have some drawbacks, such as increased management complexity and potential performance impacts, the benefits often outweigh these disadvantages. By offering granular control, personalized protection and portable security, host-based firewalls are a valuable tool in any cybersecurity strategy.

Read our complete guide to network security to learn more about firewalls, malware protection, and other best practices.

Collins Ayuya
Collins Ayuya
Collins Ayuya is a contributing writer for Enterprise Networking Planet with over seven years of industry and writing experience. He is currently pursuing his Masters in Computer Science, carrying out academic research in Natural Language Processing. He is a startup founder and writes about startups, innovation, new technology, and developing new products. His work also regularly appears in TechRepublic, ServerWatch, Channel Insider, and Section.io. In his downtime, Collins enjoys doing pencil and graphite art and is also a sportsman and gamer.

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