Best Free Firewall Protection

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Firewalls help monitor your system's communication between your network and the Internet to help stop intrusions and attacks. They are particularly useful for controlling the activities of Internet facing applications.

No other freeware product has more of a reputation for causing user angst than a firewall. To find a suitable product may involve a process of trial and error. A firewall should protect while not being too intrusive or too complicated to handle. In this article we give you a selection of what we think is the best free firewall software available today. Our recommendations are made taking into consideration both editors' and site visitors' opinions.

Firewalls come in two flavours; software based and hardware based. To avoid potential conflicts only install one (third-party) software firewall. You can improve protection, however, by using a hardware "firewall" (such as a router) and a software firewall in conjunction. Modern routers usually have a built-in firewall; consult your router documentation for more details.

Basic firewall protection is critical for securing your PC. Simple firewalls (like the default Windows firewall) limit access to your system and personal information, and silently protect you from inbound threats. We review basic third-party firewalls that have marginally better security than the Windows firewall, such as simpler features for monitoring programs that request outgoing Internet connections (we call this "outbound protection"). The default Windows firewall has only limited outbound protection.

Proactive firewalls have the most 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.

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. It's an excellent option for high risk users (check out our Security Wizard to see if this includes you). However, it's plausible to argue that a good resident antivirus will stop some malicious threats before they get a chance to make it to the Internet anyway. Many of the top antivirus programs are starting to provide behavioral blocking and extended scanning of network activity.

It's important to use basic or proactive firewall protection, antivirus software for active protection, and safe practices from our "most important advice of all" (Security Wizard) in order to minimize the risk of malware on your PC.

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.

Review Index

Additional Tips

  • Before installing new resident security products, including antivirus and firewall programs, you may want to make 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. Windows Vista (Ultimate) and Windows 7 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.
Basic Firewalls



The built-in Windows firewall is a common choice since it passes all inbound tests (both stealth and open port) and doesn't have many popup alerts. It doesn't require installation, so it's not likely to conflict with your other programs. And many average users may not reliably handle the popup alerts of the best firewalls on the market (especially at their max settings).

If you scan clean for malware and you don't want/need the additional features of a third-party firewall, then the Windows firewall could be a practical and useful solution.

Alternatively, you can replace the Windows firewall with a basic third-party firewall for easier control of outbound protection and additional features. Most simple two-way firewalls ask you to allow or deny Internet access for unknown programs. Many automatically allow trustworthy apps and remember your decisions to become silent over time.

First, you can convert a proactive firewall into a basic two-way firewall, making some of the best free firewalls behave with similar silence and protection as ZoneAlarm. Select the following one-click configurations to set them (see the proactive section for more on them):

  • Online Armor Free: Right-click its tray icon > uncheck the "Program Guard". It's a user friendly option for this configuration if it doesn't conflict with your other software.
  • Comodo Internet Security: Right-click its tray icon > set "Defense+" to "disabled". Or select the "Firewall only" configuration during installation. Make sure to enable rule creation in 'firewall behavior settings' (so you can modify program rules later).

Second, additional third-party firewalls behave similar to the basic configurations of proactive firewalls above. ZoneAlarm, for example, has made a comeback with fewer popups and lighter resource use.



Basic Firewall Reviews

ZoneAlarm Free Firewall  is an excellent inbound/outbound OS firewall solution suited for users of every level of experience. ZoneAlarm protects systems from intrusions as well as program access to the web. ZoneAlarm features an easy-to-understand user interface. Users can adjust security settings for their needs to allow for file/printer sharing, public networks, and even turn off the firewall if ever needed. Simple controls in the form of visual slide bars make setting up this firewall a snap. ZoneAlarm offers to help users setup initial program access with a first-run scan of installed software and allows/denies accordingly. This first scan does not always offer accurate access to programs.

Users will have to interact with this firewall for a time after installation to make sure programs needing LAN or internet access are granted proper permissions. Popups are very simple in format offering Deny, Accept, and a checkbox a user can check to make ZoneAlarm remember the decision. Novice users should be able to easily identify the name of the program asking for web access so they can make the appropriate decision.

The Program Control will allow users to set ZoneAlarm for Low, which is a learning mode and no OS firewall protection and limited popups. Or users can choose Medium, which will make programs ask for permission to access the trusted and internet zones. The high setting is not offered in the Free version of ZoneAlarm. The Smart Defense Advisor will help reduce popups by offering settings for programs asking for access, based on the decisions made by other users worldwide. Users can choose whether or not to participate in ZoneAlarm's community defense program. Users can set programs access manually at anytime by going to ZoneAlarm's Program Control and selecting Programs.

Internet Zone controls are divided into the Trusted Zone, used for the local network to share files, printers, etc., and the Internet Zone for communication to/from the web. A simple 3-position format allows users to choose from "No protection" (firewall is off), Medium (Allows file/printer sharing), and High (will allow users to connect to a network but will not allow anyone else to connect to your system). The medium setting is recommended for home networks with more than one system, and for users whose modem requires this setting. The high setting is most recommended for single-system web access (only one computer at home and modem does not require a home network setting), and for public areas such as cafes, restaurants, and hotels (etc.) with wifi.

ZoneAlarm Free offers basic two-way defense, stealth mode, and anti-phishing protection. However, it lacks HIPS or program-to-program protection.

It is worth noting that there have been many negative comments about the latest version of the software, at least from the visitors on our site. Most notably, many features have been removed, and may be regarded as a step down from previous versions. Perhaps something you may want to take into account when choosing a firewall product.


Windows 7 Firewall Control Windows 7 Firewall Control is a good choice for those intending on using the Windows built-in Firewall. Despite its name, the program is compatible with Windows XP and higher. In a nutshell, Windows7FirewallControl allows the user to configure the Windows firewall to block or allow applications from connecting to the internet; it adds better outbound protection configuration to the built-in Firewall. It is based on the Windows Filtering Platform (which is what the built-in firewall is also based on), so unlike most other firewalls it does not install any third party drivers. The user interface is clean and simple, reflecting what this program does (ie. block or allow application access - nothing more).

There are three modes a user can choose from; Normal, DisableAll, or EnableAll. DisableAll disables all applications regardless of program settings, while EnableAll allows all application access (essentially equivalent to switching off the firewall completely). Unless needing to test something specifically, the Normal Mode is the recommended one - applications/programs are allowed or denied access depending on the rules set.

Under the Normal Mode, when a program tries to access the internet for the first time (upon installation of W7 Firewall Control) a window pop-ups with information on what the application is, the publisher, etc (assuming default program settings). You can then allow or disallow access, either permanently or as a one-time basis. Selecting the former option will add the settings permanently to the Programs list, while with the latter option you will have to deal with the pop-up window again on the next launch.

In addition to the window pop-up for new programs, activities that take place (ie. blocked/allowed traffic, etc) are logged and shows up in the bottom right corner of your screen. Both the pop-up window and log activity notification dialogue can be turned on or off at the user's discretion.

That's basically all there is to it. It may get a bit annoying when you first starting using it, since you will have to define the initial rules for all your applications (ie. allow or disallow them); this includes everything from Internet Explorer to your antivirus program. Nevertheless, Windows7FirewallControl allows much greater and easier control over the built-in firewall than what the operating system offers.


Tinywall 2.0 TinyWall is a lightweight firewall solution that works with the built-in Windows Firewall. With no pop-ups to annoy the user, it can be an ideal set-and-forget solution. The installation package is very small, weighing in at just over 1 MB. Installation is a breeze, though there is no option for the user to select where to install the program. After installation, it starts running quietly in the background, as indicated by the tray icon. All the program features can be accessed by clicking once on the tray icon; there is no 'main window' interface. From the pop-up menu, the user can also view and select, among others, the operating mode, total network activity, adding application/process exceptions, and accessing the Firewall Settings dialog.

The Firewall Settings dialog is where the user can manage General settings, such as password protecting the application. An application exceptions section also allows the user to specify applications that are allowed to communicate with the network. There is also a 'Detect' feature where the program will try to detect known applications, or the user can elect to manually add applications. Furthermore, TinyWall is able to recognize associated processes with the same application. For example, if you have a program that has more than one process, adding the first process will result in the program also offering to whitelist the second related process as well. Needless to say this is very useful for those applications that have more than one process.

It should be noted that when adding an exception to the list, the default settings are 'Unrestricted UDP and TCP traffic'. Depending on the nature of the program it may be necessary to restrict it to 'Outgoing only' to offer maximum security.

The special exceptions tab allows the user to specify more advanced settings; specifically, allowing the user to select which system services to allow/block. It is recommended to leave it as is unless there's something you really want to change.

The maintenance tab rounds out the Settings dialog, allowing the user to import/export settings, check for updates manually, and a link to visit the vendor's webpage.

A small, lightweight firewall, TinyWall is a solid choice for those looking for a reliable, low-resource firewall program that does not interfere with the user's computer usage.

Firewalls with Strong HIPS Protection



The following personal firewalls provide excellent network and HIPS protection. Each firewall comes with default settings and shouldn't require much adjustment except for the needs of advanced users.

Firewall products in this section require more time to learn than basic firewalls, in order to get the most out of them. 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 like Matousec. 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).


Proactive Firewall Reviews

Comodo Firewall is the best choice for users seeking a full featured security suite. This latest release is suitable for both lightly-skilled users (still must have knowledge of installed programs) and technically advanced users. Its robust and active HIPS (or application monitoring feature), called "Defense+", matches or exceeds the security performance of pay products. Comodo allows for much control and customization for the curious or the paranoid.

Comodo includes a "memory firewall" (against buffer overflow attacks) and a light sandbox component to limit the way unknown applications and new software installations affect your computer. The use of sandbox protection limits the negative effects of malware. It maintains a lengthy list of known safe applications, but if an unknown application attempts entry through the firewall, Comodo will deny the application and ask the user what to do. The new release contains user friendly features by default while allowing experienced users to maintain control over ports, protocols, and configurations.

During installation the user has three firewall installation options to choose from:  Firewall Only, and Firewall with Optimum or Maximum Proactive Defense (ie. the Defense+ feature as mentioned earlier). After installation Comodo automatically selects "Safe Mode", which generates numerous popup alerts for applications not in its trusted vendors list (you can browse this list to see if you trust the vendors: go to the Defense+ tab > "Common Tasks" > "View My Trusted Software Vendors"). When you answer "allow" and "remember your answer" to popup alerts for an application, Comodo creates a custom policy for it. Some of its policies are fairly liberal.

In the more liberal "Clean PC Mode", Defense+ automatically treats all applications on your drive as safe (but if any malware is currently hidden on your drive, it too would be considered safe). Applications still receive some minimal monitoring for Comodo's two protected lists ("my protected registry keys" and "my protected COM interfaces") and for running as an executable, or more/less monitoring depending on their custom policy. And new files get sent to a list of files "waiting for your review" in the "Summary" page. Files listed for review will be considered possibly unsafe and will provoke popup messages, as if in Safe Mode, until their custom policies are made.

Comodo limits the frequency of alerts by automatically treating some programs as safe and allowing some applications to access the Internet. You can additionally automate the behavior of Defense+ by one or more of these methods for treating applications as safe:

  • Have it "remember your answer" to all popup alerts when an application first runs, which works for some applications (because some custom policies set this way are close to "trusted" status). But if an application still nags you, click "More Options" in the alert and use the drop down box to select "trusted" or "blocked" (etc.), if available, or set an application to trusted manually ("Defense+" > "Advanced" > "Computer Security Policy" > "Edit..." > "Use a Predefined Policy"), which finally ceases popup alerts and most intrusion prevention for that application.
  • Add files to the lists of "My Own Safe Files" or "My Trusted Software Vendors" in the interface (see the "Defense+" tab), which is most helpful for "Safe Mode" or "Paranoid Mode".
  • Use the "Clean PC Mode" (right-click the tray icon and select it under the "Defense+ Security Level"). But make sure to scan and remove any malware first.

The following guides by Gizmo's Freeware also contain many useful information about Comodo's settings: How to Install Comodo, How to Tame Comodo Defense+ Without Disabling It, and MC's Mini Tutorial.


Online Armor FirewallA solid contender is the free version of Online Armor Free. It has outstanding leak-test and HIPS performance (the HIPS feature is mostly in its "Program Guard"). It has a unique feature called "run safer" that allows you to selectively set risky applications (web browsers, office software, readers/viewers, instant messengers, email or news programs, multimedia software, download managers, etc.) to run as if under a limited user account (go to "Programs" tab > uncheck "Hide Trusted" > highlight a program and click "Run Safer"). It minimizes popup alerts over time with its automatic list of safe programs, your on-demand scans with its safety check wizard, and your responses to popup alerts -- especially in cases where you tell it to remember your decisions and have it treat programs as trustworthy.

Run the wizard and have it search your PC for known programs to allow/block/ask. In this case, Online Armor relies on you to respond to alerts for unknown programs. For the curious or paranoid user, it uses excellent popup messages when it automatically allows a program to connect online and, optionally, when it automatically trusts a program/process to run (these alerts don't require user action and they can be enabled/disabled in the interface with "Options" > "Firewall", and "Programs" > "Options"). For example, I noticed a message when it auto trusted a key logger test, but after I set the tester to untrusted, it gave very informative and detailed security alerts (and then it passed the test and logged the tester in the interface under the "Key Logger" tab, but it only logged the key logger after the test was untrusted). You can even close both its tray tools from its right-click context menu. They are not needed for the firewall and HIPS components to continue running and protecting.


Outpost Screenshots Outpost Firewall Free is a good choice for users who want highly flexible protection without sacrificing usability. It was obviously made with average users in mind, judging by the care taken to simplify alert messages and make it easy to adjust intrusion prevention (or HIPS) monitoring. For example, it remembers your responses to popup alerts without the need to set "trusted" rules (like in Comodo/Online Armor), and like Online Armor it notifies you when it automatically allows an application to access the Internet (especially helpful during the learning phase).

The free version lacks many extras of the pay version, however, such as automatic updates and the ability to break active connections. The HIPS component is called "Host Protection" in the interface. It provides four default levels of protection, which can be easily set with a slider and additionally customized item by item by advanced users. The default "optimal" setting only monitors the "most dangerous activities" (such as memory injections, driver loads, and a healthy list of system critical features -- auto starts, shell extensions, and internet settings) instead of all program activities. But these "optimal" settings lack protection from keyloggers, direct disk accessing, DNS API request monitoring, etc. You can check the types of reduced monitoring in "Settings..." > "Host Protection" > "Customize...".

The installation asks whether you want to train the firewall for a week (using its Auto-Learn mode and Rules Wizard). In this mode, it sets rules automatically for known safe applications.


Private Firewall A former commercial product, Private Firewall is now unrestricted freeware. It is a proactive multi-layer security solution, offering behaviour blocking technology alongside standard firewall protection. Using Behavioral-based Monitoring, it features zero-hour virus, spyware, and malware protection, process and application security, and registry protection, just to name a few. It is definitely a feature-packed firewall/HIPS solution.

 While there is a decent help file available, the user interface can be a bit confusing and overwhelming. There are many configurable settings, and sorting through them may require some time. To help out with that there is a information menu on the right of each screen which explains what each section is for. Training mode allows all actions within a 180-second interval, which is ideal for installing or running programs for the first time. On the first run after installing however, Private Firewall still managed to disable Panda Cloud Antivirus, the antivirus software on my test system, even with Training mode activated. Adding Panda Cloud Antivirus to the allow list seemed to solve this minor issue.

It is also possible to set different security levels for the Internet and the Network. Various levels of protection (High, Low, and Custom) can be separately specified for Internet Access and Network Security (ie. file and printer sharing). This is useful for, say, when one needs to access the internet via a network they don't quite trust. In addition, there are three profiles you can choose: Home, Office, and Remote. You can set appropriate settings for each one and easily switch between them as needed; this is particulary useful for portable computers which connect to many different networks. Another useful feature is that it is possible to block all outbound email; simply click the 'Block Outbound Email' icon in the main user screen and all outbound email should be blocked.

Overall, Private Firewall is a very effective firewall; it ranks among the top products on Matousec. A number of members at our forum speak highly of the developers of Private Firewall, and the software is trusted. However, the graphic interface and usability is slightly tailored for the more advanced users. Beginner computer users may want to consider another firewall instead, but if you are comfortable with the basics of Windows & firewall software, you should definitely consider Private Firewall.


AVS FirewallAVS Firewall differs from other regular ones in that it comes with additional protection modules; namely a registry defender, a banner blocker, and parental control options – it is something like a suite. The firewall itself does not have as many configurable options as some of the firewalls listed on this page, but the standard selections are still there – off, which turns off the firewall; custom, which allows you to set your own connection rules; and high, which blocks all connections.

Each section of the program is displayed clearly; navigation is through the menu on the left. Alerts are generally clear and straightforward, as is configuration.

The registry defender protects the registry from being modified, with the option of only protecting select categories. The parental control limits the list of websites that can be accessed, but you must manually add each website to be trusted, ie. You cannot block specific websites; you can only allow certain websites. The anti-banner component blocks undesirable web page content including ads, flash banners, pop-ups and the like. All three of these additional modules can be disabled independently as desired. AVS Firewall also comes with a monitoring utility so you can check the size of network traffic which is sent and received by each application.

During installation of this firewall, the installer automatically installs the AVS Software Browser; there is no option to opt-out of installing this, but the program can be removed separately after installation with no effect on the actual firewall program. The installer also has a pre-checked option to install AVS Registry Cleaner, and it is recommended that it is unchecked so the installer does not install it.

Despite trying to bundle in a few additional programs by the vendor, AVS Firewall itself is a decent firewall program.  It has some additional features not found in your everyday firewall program, though most of those features can be found in other third party programs.


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Quick Selection Guide - Basic Firewalls

Windows 7 Firewall Control
Runs as a stand-alone program on a user's computer
Simple and effective; uses Window's built-in firewall platform so no third party kernel drivers are needed. Very small footprint. Three modes to choose from (Normal, EnableAll or DisableAll). Great for complementing Windows' built-in firewall
May be a bit annoying to use at first since the user must configure the initial rules for all their applications; no training mode. The dialog box that pops up to allow/disallow a particular program has a lot of information, some of which may not be too user friendly to beginner computer users. Online manual could be more comprehensive.
1.43 MB
32 and 64 bit versions available
Feature limited freeware
A portable version of this product is available from the developer.
Windows XP, Server 2003, Vista, 7, Server 2008

Despite its name, this program works with system Windows XP and higher

Runs as a stand-alone program on a user's computer
Lightweight basic firewall; simple yet effective. Non-intrusive program with no pop-ups. Ability to recognize associated processes when whitelisting programs. This program could be a good choice for those not familar with computers, as it does not require advanced knowledge to use.
No user dialog; everything is accessed from the pop-up menu. Not necessarily a bad thing, but may be different compared to what most are used to. Cannot select where to install the program. Requires .NET framework
32 and 64 bit versions available
Unrestricted freeware
There is no portable version of this product available.
Windows 7, Vista
ZoneAlarm Free Firewall
Runs as a stand-alone program on a user's computer
Solid inbound firewall, stealth mode, user friendly, customizable settings, anti-phishing protection, and hosts file lock.
Inadequate HIPS or program monitoring protection. No High setting for program access in Free version. In spite of available automatic update option, updates almost always must be performed manually. Help file designed for commercial version. New version (v10) has received negative feedback from our visitors
32 bit but 64 bit compatible
Free for private use only
There is no portable version of this product available.
Windows XP (32-bit), Vista, Windows 7 (2 GB RAM, 2 GHz, 100 MB disk space)

To learn more visit its service and support page

Quick Selection Guide - Firewalls with HIPS

Gizmo's Freeware award as the best product in its class!

Runs as a stand-alone program on a user's computer
Effective proactive security and stealth, one of the lightest of all tested firewalls on memory, simple setup (no nags or ads!). Easily choose between 3 network profiles. Has a unique "email/system anomaly detection" feature, which trains over 7 days by default. Quick to respond to queries / feature requests.
No automatic installation mode (but it has a training mode in "Settings" > "Advanced"). The tray icon flashes for log events instead of network activity per se. Program may be more suitable for advanced users due to slightly complex user interface.
32 bit but 64 bit compatible
Unrestricted freeware
There is no portable version of this product available.
XP & Server 2003 (32-bit), Vista, Windows 7 (128 MB RAM, 300 MHz, 10 MB disk space)

Additional Features of Interest (as Found in its Interface): Built-in help and tips. Auto trusts safe vendors. Able to block outbound email automatically. Network options for experts, with three default settings to modify (Home, Public, Work).

To learn more visit its feature list and online support (change log, user guide, & tutorials).

Comodo Firewall
Runs as a stand-alone program on a user's computer
Its Defense+ HIPS performance exceeds commercial products and leads the class, it includes a "memory firewall" feature, and it allows you to quickly switch between Defense+ security modes and configurations. Includes automatic updates. Installation can automatically configure your PC to use the Comodo SecureDNS (but you can do this without installing CIS).
No built-in help. Despite not installing the AV component, the AV files are still placed in the Comodo program folder. Possible problems when uninstalling program; remants of the program are sometimes left
88 MB
32 and 64 bit versions available
Unrestricted freeware
There is no portable version of this product available.
Windows XP (SP2), Vista, Windows 7 - 152 MB RAM, 400 MB disk space

Additional Features of Interest (as Found in its Interface): Installation mode/training mode, auto updating, built-in help and tips, parental control with password protection, extra themes and languages, and a stealth ports wizard. Purges old or unused firewall/Defense+ policies or unused files (safe files, files waiting for review, etc.). Displays balloon messages for instant logging events.

To learn more visit its forum, online help, and/or release notes.

Outpost Firewall Free
Runs as a stand-alone program on a user's computer
Proactive security (at max settings) compares with Online Armor. Highly flexible protection, simplified alert messages, and includes a full screen mode.
It fails tests for protection against malicious logouts or system shutdowns. The free version lacks automatic updates and the ability to break active connections.
2009 - v6.51
16.63 MB; 98.81 MB for Security Suite
32 and 64 bit versions available
Feature limited freeware
There is no portable version of this product available.
Windows 7, Vista, XP - 450 MHz CPU, 256 MB RAM, 200 MB free disk space

Newer versions and 64-bit version are part of the Outpost Free Security Suite - includes additional software components which may conflict with existing software.
64-bit version (98.81 MB v7.1) available here: *Warning: Downloads from Cnet ( now require the use of a proprietary installer.

Reduced HIPS monitoring (lacking anti-key logger protection for example)

Additional Features of Interest (as Found in its Interface): Built-in "Help", full screen mode or entertainment mode.

Online Armor Free
Runs as a stand-alone program on a user's computer
Excellent proactive security performance. Includes a "run safer" feature to reduce rights for specific risky applications, and the ability to monitor key logger activity and host files. It handles the installation of new programs better than some other tested products.
It doesn't have automatic updates or a built-in help. It's mandatory to enter an email during installation, and it has a pre-checked option to send it anonymous information. May have problems installing unless all remnants of similar programs have been removed from the receiving computer.
30 MB
32 bit but 64 bit compatible
Free for private use only
There is no portable version of this product available.
Windows XP (32-bit), Vista (32-bit), 7; 512MB Ram, 50MB Disk space

64-bit version only for Windows 7; XP 64bit and Vista 64bit are not supported

Additional Features of Interest (as Found in its Interface): Set passwords, protect programs (right-click > "Advanced options"), key Loggers tab/Hosts tab, and multi desktop support.

To learn more visit its forum, and blog.

AVS Firewall
Runs as a stand-alone program on a user's computer
Has additional features not found in standard firewalls (registry defender, banner blocker, parental controls). Clear and straightforward navigation. Easy to configure
Parental control only allows you to add trusted sites; you cannot specify specific sites to block. Installer automatically installs AVS Software Browser which is not necessary for the firewall program, and has pre-checked option to install the vendor's Registry Cleaner. Firewall itself is not as configurable as others
32 bit only
Unrestricted freeware
There is no portable version of this product available.
Windows 7, XP, 2003, Vista

Have Your Say

Your opinion matters! If you've used one of these firewalls before, or know of another outstanding freeware firewall, let us know in the comments section below. For a more comprehensive discussion, please visit our forum.


This software category is maintained by volunteer editor Tim; registered site visitors can contact Tim by clicking here 

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by CaptainSparks (not verified) on 26. May 2012 - 8:46  (93974)

Many thanks for that info, Tim. I have read good reviews about PF but was put off a bit by it not having real-time protection, which PCTFW+ did. I'll consider it, though, as it seems to be gaining a lot of support.

by CaptainSparks (not verified) on 26. May 2012 - 9:20  (93975)

I'm wondering now if I was misinformed about the "real-time" protection of PF. Does "real-time protection" apply to firewalls have or is that confined to AV and anti-malware/spyware programmes?

by MidnightCowboy on 26. May 2012 - 11:43  (93985)

This is something of an oversimplification :) but there are basically two kinds of realtime protection, those confirmed with a “signature”, and those not. Most AV's have both but unless they are integrated into a suite, firewalls use method two (in addition to their normal packet filtering functions). They apply a variety of algorithms as may be included in their code. This could be simply “you've just clicked to install program “X”, do you want to continue?” Otherwise they will know where certain programs and services should be located within Windows and will monitor your system for signs of unauthorized “intrusion” (something in the wrong place) which is a typical malware behaviour. Another is an attempt by one process to manipulate another, and so on. The advantage of this approach is it doesn't require signatures to function, and as the AV vendors can never keep pace with these, it supposedly gives users a head-start against so called zero-day malware. The disadvantage is much of this cannot be reliably automated so users are required to make the decisions to allow or deny events (alerts) themselves. A considerable knowledge of Windows systems is required to get this right because a wrong decision could render your machine inoperable. Some of these programs are better then others in terms of performance and reliability, and PrivateFirewall is at the top of the pile. This program has seen considerable development over the past few months and whenever an issue was found, the fix release was out sometimes within 48 hours.

by CaptainSparks (not verified) on 26. May 2012 - 14:43  (93997)

Thanks, MidnightCowboy. It never is simple, is it? I appreciate the differentiation.

by j mac (not verified) on 21. May 2012 - 19:44  (93807)

I don't fully understand why all the stink raised about ZoneAlarm 10.1 free firewall? It works quietly and seamlessly with my Windows pc. Am I missing something? I think I'll stick with it.

by t i m on 26. May 2012 - 8:02  (93972)

Glad it's been working fine for you :) Each system is different so software may behave differently on various machines

by Rohn (not verified) on 15. May 2012 - 8:50  (93485)

I also have used Zone Alarm with confidence for many years.....until recently, that is. In a moment of absentmindedness I clicked on an Update offer and have had nothing but trouble ever since. So, I thought, I'll uninstall Z.A. and re-install an earlier version. Think again, it is impossible for me to get rid of it. I tried Windows 7 Firewall as an interim, but Z.A. kept appearing even though Revo Uninstaller thought it had got rid of it all. Through trial and error I have been able to delete a couple of what must be important dll's so it no longer interferes with Windows 7 Firewall, but many parts are still loaded in my Program files under
"C/Program Files/CheckPoint", and unless I can find a way to get rid of them, it looks like they are there to stay.

by t i m on 21. May 2012 - 2:30  (93768)

Hm, maybe you can try another uninstaller? We have some on the Best Free Program Uninstaller page.

Or you can try posting in our forum and someone should be able to help you troubleshoot getting rid of ZoneAlarm.

by Therese S. (not verified) on 30. June 2012 - 4:55  (95568)

I too had trouble with the new Zone Alarm back when it came out, the only solution I found was to use Windows restore feature to go to before the update was installed. I'd recommend anyone experimenting with Zone Alarm updates do a system backup first, so you can restore without losing anything else you do want to keep.

by Trefaynie (not verified) on 10. May 2012 - 13:58  (93311)

I was looking for a new firewall, so I had the google to find the best free firewalls and now I am here. Really good reviews, and I am always in need of users' opinion and reviews to choose a good one.

I have used Zonealarm for several years, until now. The verion 9.2 was installed because it was the most stable version of it.

Pros are the easy install, automatic setup for installed programs, showing internet process on tray icon, full screen view of program window, less annoying warnings, nearly good work.

Cons are forgetting of some preferences, sometimes longer boot time of computer, remembering all program files executed and no cleanup option of this list, automatic update mostly not works, in some special cases program cannot start in boot, must be loaded manually.

I have downloaded the latest version but it is a piece of junk.

Pros of v10.1 are not really known for me. Do you know any?

Cons of v10.1 are the chaotic setting options, main program window is small and has no resizing option, automatic setup is not as good as in earlier versions, too much menus and options with no help, no process view in tray icon.

So I am almost in certain of installing COMODO Firewall instead of Zonealarm, maybe it will be a better choice for securing my computer.

by t i m on 21. May 2012 - 2:25  (93767)

The feedback about ZA v10 has been pretty much negative all around..maybe the only pro is that the number 10 is greater than 9.

Anyways, hope Comodo does the job for you. Let us know how it goes

by Trefaynie (not verified) on 1. June 2012 - 7:54  (94267)

I have uninstalled ZA (sooo slow and problematic) and installed Comodo Firewall (without antivirus) after that.

I DO really like the kind of firewalls which asks for permissions of programs often and not works silently in the background. CA lets me know everything about processes working behind and asking about program accesses to internet more often than ZA did. Also a great function that I can choose the permission type of program, it is temporary or permanent, trusted or untrusted, browser or FTP client.

BTW, Comodo Firewall has an easy and fast installer with customizing options.

After installation the response and booting time of computer was significantly better and reduced. Booting time with ZA was about 3,5-4 mins but it is about 2 mins nowadays!

The built-in options, the multi-language use (mine also among them), the precise setup, the learning mode make CF much more stable and user-friendly than ZA.

Security policies of firewall are easy to be set up and customized, adding and editing trusted and untrusted programlist is easy, the online manual of using program and options are clear and detailed quite good.

The "Defense+" part looks really effective and detailed in showing currently running processes and has "running in sandbox" option also!

Though it looks perfect, I am missing a few important options (IMOP is it important): e.g. the frequent updating of program. (must mention that it was also a missed option in ZA), a built-in malware scanner could be also useful, updating lists of known trusted programs.

Personal rating of CF is 9,5.

by CyberWolf64Again (not verified) on 16. May 2012 - 20:00  (93561)

Downloaded Comodo Firewall about 2 weeks ago.
NOT bundled along with AV and that.
What you have to do is get the FIREWALL only (with HIPS of course). NOT Comodo Internet Security which has all that other stuff shoveled in there as well.

GREAT product. I had been using Online Armor Free, BUT, after removing it and installing Comodo, I IMMEDIATELY noticed one thing... My download speeds had risen DRAMATICALLY. Avg. DL speed under OA was about 2.5 mega bits/ sec. Under Comodo, was about 4 megabits. Peaked at almost 6 megabits.

by doctorlogic (not verified) on 6. May 2012 - 16:13  (93130)

Commodo is certainly the best free firewall at the moment. But all the contenders are taking the same approach to attract the mass market who don't want (or don't know how) to configure a firewall for themselves.

So we now have firewalls that are pre-configured for well known software to allow them to open all the ports and back-doors without asking our permission.

Some of us would prefer to have a firewall that starts with all of the doors in and out of the computer firmly shut, so that we will know when even the operating system wants to phone home or automatically download something to alter the configuration of our computer.

There should be an option so that we can allow only the minimum of communication in, and out through the firewall necessary for the computer to be able to function. We don't want lots of other services to operate in the background without being informed, because every breach of the firewall is a potential security risk.

by t i m on 21. May 2012 - 2:20  (93766)

That's a good point you mentioned. Although some firewalls do have an option where you can set the security level to be the highest. That *should* give one the highest possible protection

by blues on 25. April 2012 - 18:40  (92466)

My two favorites are PrivateFirewall and Online Armor. Both offer excellent protection (Firewall/HIPS/Anti-Logger) as well as the ability to run apps with limited rights.

PF is a very elegant solution. The download is a tiny 3.6 megs and the installation is a snap. It fully integrates with the Windows Security Center and replaces the Windows firewall automatically. Your personal settings can be exported and imported as needed.

Online Armor is a bit more refined in terms of its user interface and its alerts are somewhat clearer and easier to comprehend, especially for those with limited experience with firewall/HIPS apps. It also integrates with the Windows Security Center and replaces the default Windows firewall.

Though both PF and OA can be run quite simply with default settings, each has a number of options to tighten security to personal requirements.

The only knock I have against OA these days is that it runs quite a bit heavier on my XP Pro SP3 system compared to PF and sometimes consumes quite a bit of CPU for extended periods of time. PF runs much more quietly and unobtrusively on the same system and as a result that is what I use. It has proven to be the perfect complement to my other security apps and has garnered excellent scores when tested on's Proactive Security Challenge.

I highly recommend both products and give a very slight edge for the "newbie" to OA which can take a bit more of the decision making out of the installation and setup process. That said, I don't think that anyone should be disappointed by opting for either one. Each is suitable for novices through those users with much more advanced skill sets.

by t i m on 3. May 2012 - 6:32  (92955)

Thanks for the detailed comments! I agree with all your points. PF is great and would arguably edge out OA overall featurewise.

If PF could refine their interface to be more user friendly, it would probably be a one of the best, if not the best, firewall product.

by blues on 3. May 2012 - 15:00  (92970)

Thanks for the good words, I appreciate it.

I know from having discussed the matter via email with Greg Salvato, that an updated user interface is something they have in the plans but I don't have any information regarding how soon that may be implemented. Still, it's really not all that bad "as is" and if one downloads the user manual (.pdf) from their website, it makes a handy reference when any questions arise.

That said, I've been very impressed with how far the product has come and how quickly the development team has been able to add enhanced features.

by t i m on 8. May 2012 - 5:05  (93194)

Agreed, it's certainly not bad at all (far from it). However in my opinion it just does not seem to be quite as user friendly for those not too familar with computers; veteran computer users would probably have no problems working with PF. That being said, we're probably just being picky about it, as it's a great all-round, no-nonsense firewall solution that works well.

Great to hear that an updated user interface is in the works, thanks for letting us know about that! Perhaps a wizard setup-type interface might be beneficial too, where PF can lead the user step by step through various configurations; then the advanced user can manually configure any further settings.

I've also heard good things about the development team and how quickly they address issues & features; it's definitely a product worth keeping a watch out for.

by blues on 13. May 2012 - 21:03  (93418)

I finally succumbed to curiosity and after backing up my system with a new image decided to try out the Comodo firewall.

I followed the excellent installation instructions provided by Chiron (linked above in your review) and only made a couple of small modifications to tailor the security a bit more to my liking.

Thus far, I am impressed with how smoothly and quietly Comodo is running alongside my other security apps. In this regard both Comodo and PrivateFirewall are far superior to Online Armor which unfortunately has not played well with my XP Pro SP3 system in its recent incarnations.

The utility and available features included in the Comodo Firewall are impressive but I must say that without the installation guide I don't think I'd have found tweaking and enhancements all that intuitive. Everyone is different and perhaps it simply comes down to familiarity...but for me I think that both OA and PF are a bit more intuitive in this regard. That said, if someone is going to stick with a default installation, it seems to be relatively straightforward.

Long and short of it is that those looking for an excellent firewall/HIPS combination should be able to find one that fits their needs and system requirements with any of these three terrific programs. Those willing to experiment will most likely be rewarded with one that feels just right.

by t i m on 21. May 2012 - 2:17  (93765)

Glad you've found Comodo to be suitable as well. Agreed they're all different and one may want to experiment to find the right one suitable for them.

I guess you're going to stick with Comodo as your firewall now?

Also, a word of caution though to anyone considering trying out multiple firewalls: I have had problems with Comodo products not properly uninstalling - component remains were left behind and some issues were caused there. While there were no problems uninstalling on the test system (using a near-fresh copy of Windows), and everything seems to have been removed properly, anybody considering trying out all three firewalls may want to create a restore point and/or system image (as blues did here) just in case.

by blues on 21. May 2012 - 2:43  (93769)

I've had it installed for just over a week now. I'll try to give it sufficient time to make a fair evaluation and then decide if a return to PrivateFirewall is warranted or not.

So far, so good...with no issues to report. Fortunately, I was able to get some excellent advice along the way.

by t i m on 26. May 2012 - 8:01  (93971)

Cool sounds good! Thanks for the updates. You really can't go wrong with either :)

by blues on 14. June 2012 - 15:15  (94358)

After some weeks with Comodo and a short stint testing Outpost Pro Firewall (which had some issues with my XP Pro SP3 system) I'm back to PrivateFirewall.

While Comodo ran quite well, PrivateFirewall is the lightest of the three.
Also, unlike Comodo or Outpost, the app is not regularly in touch with the mother ship, uploading files or downloading updates to various databases and making changes to the setup.

I find PF to be the most intuitive to use of the three options though each person will probably find that their own comfort level varies from one app to the other.

Of the several Microsoft Security updates I attempted to install yesterday, Comodo gave me fits with one of them. After removing Comodo and reinstalling PF, the installation of that final update was done without any drama.

I don't think anyone will be disappointed with the security provided by any of these three firewall/HIPS combinations, but for me PF is simplest to install and setup, has a very small footprint, doesn't receive its orders from the mother ship (though you can easily just use default settings if desired) and its responsiveness to customer service requests is second to none in my experience.

Hopefully some of this info will prove useful to those trying to make a decision on what firewall/HIPS will work best for them.

by kjohnny76 on 19. April 2012 - 15:43  (92291)

What Is Up With comodo DNS Does It Still Use The Same DNS #s Are Could Some One Tell Me If There Is A Better DNS Please. I Am Use WIN Xp SP3 With Avira Free comodo Firewall comodo Dragon Browser. If Someone Could Help Me With A DNS comodoDNS Was Working Fine Then i Dont Know What Happen.

by t i m on 3. May 2012 - 6:30  (92954)

Not sure what the problem exactly is? Is ComodoDNS not working properly?

by art.kevinc on 22. March 2012 - 21:25  (90994)

AVS firewall doesn't seem to be recognised as an installed firewall on my laptop. It reads as windows firewall is turned off.

by t i m on 24. March 2012 - 6:01  (91049)

You can turn off firewall monitoring by Windows:

by art.kevinc on 25. March 2012 - 17:26  (91135)

Does this usually happen with AVS firewall? Mainly I'm concerned if its my laptop alone that has the problem.

Thanks for your help.

by t i m on 26. March 2012 - 6:51  (91167)

On the test system it's not recognized by Windows either so it's just the software itself that doesn't support it, and not a problem with your laptop. Thanks for pointing that out!

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