Firewalls help monitor your system's communications between your network and the Internet, to help detect, alert, and prevent intrusions and attacks. They are particularly useful for controlling the activities of Internet facing applications, ie. applications that access the internet.
Ignoring this layer of security may eventually result in a breach, which can result in more than just lost data. Especially for companies, the embarrassment and loss of public face could have them soon investing in business reputation management as a part of their recovery process. Time spent looking for the right firewall solution is indeed time well spent.
Firewall products can be one of more cumbersome software products to use and have a history of causing user angst. To find a suitable product that meets individual users' needs may involve a process of trial and error. A good firewall should be able to protect the user at a near-perfect level, while not being too intrusive or complicated to handle. In this article, we give you a selection of some of the best free firewall software, in our opinion, that is available. Our reviews and recommendations are made taking into consideration both editors' and site visitors' experience, opinions, and comments. As always, if you have more to share on your experiences with the software products mentioned and/or freeware firewall products that you like, we would like to hear from you. Please refer to the comments section at the bottom of this page.
Firewalls come in two flavours; software based and hardware based. Software based firewalls (which is what we will cover in this article) reside on your machine, running in the background to keep a watch on things. To avoid potential conflicts, only install one software firewall. In order to achieve the best combination of protection, we would strongly suggest to use a hardware firewall (such as a router) in conjunction with a software firewall. Modern routers usually have a built-in firewall, helping to filter out content before it reaches your machine; consult your router documentation for more details. In situations where a hardware firewall is not available (eg. a public network), having a software firewall is even more crucial.
Basic firewall protection is critical for securing your PC. At a basic level, firewalls limit access to your system and personal information, and silently protect you from inbound threats. We review basic third-party firewalls as well as the built in Windows firewall, and look at features such as monitoring programs that request outgoing Internet connections (we call this “outbound protection”).
Basic firewalls generally only have limited protection; proactive firewalls offer more extended protection, including HIPS or program monitoring (HIPS Explained), and watch for malicious behavior before malware gets a chance to take control of your PC or turn it into a botnet drone. They seek to achieve stronger “2-way” protection, preventing programs from broadcasting your personal information to the Internet. The downside of such firewalls are that it may be harder to use and/or require more memory consumption. Also, there is a greater risk of HIPS software causing conflicts, errors, or otherwise cause other issues with your PC.
Some kinds of malware are best detected by their behavior, so a proactive firewall (or firewall/HIPS combo) is a solid second layer of protection next to your antivirus program. Many of the top antivirus programs also provide behavioral blocking and extended scanning of network activity. Therefore, to best minimize the risk of malware on your PC, it is important to use a basic or proactive firewall protection, as well as antivirus software.
You can “upgrade” (for free!) your security by reading the documentation and learning about proactive firewalls or HIPS programs, or using other protection like least-privileged user accounts and/or Sandboxie or GeSWall. This information, and more, is available on various parts of our website; check the end of this article for related document links.
The built-in Windows firewall is a common and popular choice since it passes all inbound tests (both stealth and open port), doesn't have many popup alerts, and doesn't cause system performance issues. It also does not require a separate software installation, since it comes built-in with modern versions of Windows. The built-in Windows firewall has improved drastically from earlier versions of Windows; the latest iteration, Windows 10, now contains a very capable and reliable built-in firewall solution, which is named Windows Defender Firewall.
You can also replace the Windows firewall with a basic third-party firewall which can provide greater control of outbound protection and additional features. Most simple two-way firewalls ask you to allow or deny Internet access for unknown programs. Many also automatically allow trustworthy apps and remember your decisions to become silent over time. However, these software require additional configuration of settings, especially at the outset. With the improved functionality of the built-in firewall in Windows 10, such third party firewall solutions are decreasing in popularity.
A firewall built into Windows with no separate installation required.
A lightweight firewall solution that works with the built-in Windows Firewall.
A good choice to supplement the Windows built-in Firewall and compatible with Windows XP and higher.
A well-established inbound and outbound OS firewall solution suited for users of every level of experience.
Firewalls with HIPS Protection
The following personal firewalls provide an advanced level of network and HIPS protection. Each firewall comes with default settings and, depending on the users' needs, may or may not require much adjustments.
It should be noted that firewall products in this section require more time to learn and configure, and are more complex to use than basic firewalls. There is also a higher risk of conflicts and problems arising on your system. Since firewalls are often praised for their security effectiveness at their max settings, users will likely have lower protection than mentioned by independent testing sources, such as Matousec, for practical day to day use. All of the product vendors seek to provide user friendly features, sometimes incorporating reduced levels of protection in their default settings by decreasing some HIPS monitoring. In other words, these firewalls may be more suitable for more advanced users, as well as those that are more “high risk”. We would only recommend these firewalls for these users; for average daily users, basic firewalls are likely sufficient.
A good choice for lightly-skilled and advanced users seeking a full featured security suite.
Both types of firewalls (basic and HIPS/proactive) both have their benefits and drawbacks. While HIPS software do offer greater protection and control of your machine, it naturally requires more user interaction and resources, making such software more complex. There are more settings to configure than basic firewalls.
On the contrary, basic firewalls are generally simpler to use and may be easier for the user to adjust and learn how to use it. Comparatively, they do not offer as much protection as HIPS software; for example, they cannot detect suspiciously acting software behaviour, as it primarily filters incoming and outgoing internet traffic.
If you are an advanced computer user and/or are a “high risk” user, then the increased complexity of a HIPS firewall may be the best option for you, as it offers you the maximum protection available (in this regard). However, for most average users who use their computer for regular day to day use, a basic firewall, especially the built in Windows Defender Firewall, is probably more than adequate. For these latter parties, a HIPS firewall may simply be going overboard as the increased features, complexity, and configurations are unnecessary.
Additional Tips / Precautions
- Before installing new resident security products, including antivirus and firewall programs, consider making a full drive image. By creating a full drive image you are able to restore your entire computer back to a previous state in the event your system becomes completely unresponsive. Drive imaging allows you to recover from unintentional conflicts as well as severe malware infections. Everyone's system is unique and may have old, latent drivers that may be incompatible with whatever you are installing, causing problems with your system. Newer versions of Windows have a built in “Complete PC Backup and Restore” feature, or you can use a free drive imaging program.
- To cleanly uninstall your (third-party) firewall before installing a new one, you may consider using ZSoft Uninstaller to analyze before and after the installation. If you haven't used it on your current firewall, try Revo Uninstaller (or other vendor or Windows uninstaller), check for leftover services and drivers with Autoruns, and restart your computer.
The following firewalls are now unsupported by their vendors. This means they have been discontinued and/or are no longer offered by the software publisher. While they may still be available for download, they may contain undocumented bugs or stability/security issues that will not be addressed. These reviews are archived for information purposes only. Unless you run an older Windows system with no other current firewall programs available and are unable to upgrade, we recommend using an active, supported program from the list above.
Related Products and Links
Related to Firewalls
- Comprehensive List of Firewalls (PBSLW)
- Best Free Intrusion Prevention and Detection Utility (HIPS)
- HIPS Explained
- Matousec Proactive Security Tests Analyzed
- Security Advice Wizard
- Probably the Best Security List in the World
- Gizmo's Guide to Securing Your PC
- Safe Computing in Under an Hour
- Best Free Security Diet Plan
- How to Stay Safe While Online
- How to Improve Security When Using a Public Terminal
- Best Free Antivirus Software
- Best Free Browser Protection Utility
- Best Free Adware/Spyware/Scumware Remover
- Best Internet Safety Check Freeware
- Best Free Software Update Monitor
- Best Free Encryption Utility
- Best Free Anonymous Surfing Service
- Best Free Drive Imaging Program
- Best Free Password Manager
Inbound Vulnerability Tests
- Nessus (open ports test, vulnerability scan)
- GRC ShieldsUp! (stealth test)
- Audit My PC (open ports test)
- Nmap Online (open, closed, filtered, unfiltered ports test)
- Security Space (open ports test)
- Symantec Security Scan (open ports test)
- SecurityMetrics (stealth test)
Outbound Vulnerability Tests
- Matousec Proactive Security Challenge (testing suite results)
- Matousec SSTS/BSODhook (a suite of tests for experts). It may receive antivirus warnings, but they are false positives.