Best Free Firewall Protection

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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.

Firewall products can be one of more cumbersome software products to use and have a reputation 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.

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Review Index


Basic Firewalls

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.

Windows Defender Firewall  

A firewall built into Windows with no separate installation required.

Our Rating: 
License: Commercial
Built in to Windows, no separate installation needed, simple and easy to use, effective, passes all tests, no nagging or annoying pop ups, runs seamlessly and quietly in the background, significant improvements since initial version in XP. Current iteration in Windows 10 is suitable for most daily users,
Primarily incoming connecting protection only. Advanced user interface is not user friendly - this interface may not be suitable for beginner users. Would be beneficial paired with a third party tool such as Windows 10 Firewall Control. May not provide adequate protection for "high risk" users.
Read full review...


A lightweight firewall solution that works with the built-in Windows Firewall.

Our Rating: 
License: Free
Lightweight basic firewall; simple yet effective. Non-intrusive program with no pop-ups. Ability to recognize associated processes when white-listing programs. This program could be a good choice for those not familiar 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.
Read full review...

Windows 10 Firewall Control  

A good choice to supplement the Windows built-in Firewall and compatible with Windows XP and higher.

Our Rating: 
License: Free (Limited features)
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.
Read full review...

ZoneAlarm Free Firewall  

A well-established inbound and outbound OS firewall solution suited for users of every level of experience.

Our Rating: 
License: Free (Limited features)
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.
Read full review...

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.

Comodo Firewall  

A good choice for lightly-skilled and advanced users seeking a full featured security suite.

Our Rating: 
License: Free
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; remnants of the program are sometimes left on the computer.
Read full review...


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.


Other/Unsupported Firewalls

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. 

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Related to Firewalls

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Outbound Vulnerability Tests

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This software category is maintained by volunteer editor Tim. Registered site visitors can contact Tim by clicking here.

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Your rating: None
Average: 4.3 (546 votes)


Just an FYI about my experience with PrivateFirewall. I run XP Pro SP3 and installed this app b/c I needed to block an app that I bought from checking for updates. I used it for about a week and it hosed the IP stack. I was able to to fix the stack by using an uninstaller that I use to uninstall PrivateFirewall, and then did a system restore to the point before I installed it. Needless to say, I will not soon use another firewall app. Because like an idiot, I installed it on my production PC. I should have ran it in a sandbox but forgot about it. But I also did want to say that the write-up on this app was stellar, and spot on!! Sometimes of course, this sort of thing will happen. But I do know that the IP stack was healthy before I installed the firewall. Thanks for the great site Gizmo!!

I contacted Greg Salvato the CEO of Privacyware who is always quick to respond to support queries from Gizmo's Freeware members. In this case though he is confused, as I am, by the term "hosed the IP stack" used? Also, no details were provided of what happened for you to reach this conclusion? As it stands, he is 99% certain this issue is unrelated to Privatefirewall but will happily pursue it if more details are provided. MC - Site Manager.

I sometimes get to debug crashes that turn out to be triggered by incomplete uninstalls of older security software clashing with the networking subsystem and the current security software (Norton, McAfee and ZA are the most frequent culprits), so it's worth checking that you have fully uninstalled all old security programs by using the appropriate removal tool(s). I use the list here: but I'm sure there's a link to other lists here at Gizmo's too.

Great site satrow. I've not gone there until today. Very useful information. Thanks a lot.

does anyone know if outpost security suite free is still active?

i looked at the user reviews from and softpedia and the comments are from 2011 and 2012.


A firewall is a complicated topic. There are so many variables in correctly configuring a firewall to work properly. The star ratings given to these firewalls in this review are pretty much right on the money.
Novice users, I highly recommend using Zone Alarm. You have to go a long way to get out of the novice range, without some training, or heavy study.
More advanced users, I say Private Firewall is an excellent choice. Private Firewall is my choice of Firewall, to use on my computer.
Now if you are proficient at using and configuring firewalls. Comodo Firewall is in a class all by it self. But has to be recognized as one of the best software Firewalls on the market today, when configured properly. But it has a very steep learning curve, unless you are a Pro. Good Luck!

MC, you are quite right about the dangers of RegSeeker 1.55. One has to be very careful. For example, if Opera Browser has been uninstalled, and you search for Opera left-overs, you will get pages of keys. But, if you look carefully, you will see many blue "opera" keys, but followed by "tion" - so the search has produced many keys containing "operation."

But you don't have this problem with most well-defined program names e.g. "Comodo" or "Dragon" I find the free Revo Uninstaller leaves a lot of left-overs behind, both in Windows and the Registry. So I use "Everything" to search for left-overs in the OS - "Everything" does not search the Registry.

I have used RegSeeker for years, without a problem, using ONLY the Automatic cleaner, and never have I trashed my registry.

But as you rightly say, caution is definitely required.

Thanks for the comment.

How about testing's free tweakers? The "repair all-in-one" is quite something.,,

It's probably a little unfair just to single out RegSeeker because any program of this type is capable of the same as I inferred in my original post. We do however feel a need to keep posting a warning as this software type is responsible for more unbootable machines than any other cause. The situation is not helped by the amount of posts on the web saying something like "XXX reg cleaner hosed my system so now I'm using YYY and it's much better". What users fail to appreciate is, it is not the software at fault but themselves so the original mistake is odds on to be repeated no matter which program they choose to use. Security programs are the most difficult to remove without leaving traces behind because they often "hide" pieces of themselves around your system and by their nature are very entwined into it. That said, most vendors provide a removal tool and/or specific instructions for removal. Software that doesn't uninstall cleanly by these methods I would avoid from the respective vendor in the future. Only by voting with their feet can users influence developers to provide software that will not interfere with other products after the program has been uninstalled. My own recommendation is to image your system from a clean install of Windows but before adding any security software. This enables you to replace most of what you had cleanly and quickly should difficulties arise after a failed removal, and then add your new firewall/AV combinations later. It's also worth pointing out that most vendor forums offer advice about the specific removal of third party items that may be interfering with the installation and/or performance of their own product. This is by far the better route than relying on a registry cleaner scan that by it's nature will include sometimes many ambiguous entries. MC - Site Manager.

Hi to the best website in the world! A comment on Comodo Free Firewall, which is not as it used to be. I used it for years without problems, on your recommendation. However, the latest newest version caused me nothing but trouble, would not respond to my "Allow" clicks, and had so many popups that I eventually had to uninstall it. Then I could not get rid of the left-over registry entries.

A visit to the Comodo website enabled me to download and install "Comodo Registry Cleaner" and use it "at my own risk", as it is not a Comodo product, but provided by a Comodo user, to whom I say great work! It worked marvelously and cleaned all the uninstall left-overs from the uninstall (using Revo Free). As always I did a search using RegSeeker v1.55 after the uninstall, and found over a page-full of Comodo regisry keys which would not uninstall. It was then I used the third-party Comodo Registry Cleaner which did a thorough job.

Although it did not uninstall the Comodo left-overs, it readied them for uninstall, and RegSeeker uninstalled them first shot.

Comodo Free Firewall has deteriorated: after the uninstallation, my Internet Connection was gone. It took me a whole day to fix it, and this by using, as a last resort, " (Windows Repair all-in- one): a fantastic free program available from Major Geeks. On reboot, my Internet Connection was back.

Whilst on the Comodo web site, I read numerous complaints from folks who had had the same problem of having their Internet Connection broken by the latest Comodo Free Firewall.

I have now installed ZoneAlarm Free Firewall on my Windows 7 Pro and will also install a HIPS protector as you suggest. Best greetings and gratitude to TSAlert.

Also would like to add on that, I too had the problem of Comodo not properly uninstalling; any product that causes such problems upon removal doesn't really sit well in my books. Glad that you were able to eventually uninstall it successfully, and have found another great alternative!
Many thanks for sharing your experience. Just an advisory to users who may be curious but I have seen more Windows systems trashed by the use of RegSeeker than any other single piece of software. This is definitely a tool for the experienced, as indeed are all programs capable of deleting registry keys. It is so easy to delete shared entries or keys relied upon by other services to operate and the result can render your machine unbootable. MC - Site Manager.

Could this topic be updated again in some time? Online Armor has been at version since since October 2012 and I would like to see if it got better. Also the other firewalls should also have improved. I would also like to see binisoft windows firewall control tested. Sphynx also updated there version to version 5.x.

As soon as I get the chance I'll definitely be checking them out again and improving as needed - thank you for the comment

I've been using PrivateFirewall for a while now and i'm back here to see if i can't get something better.

I've gotten a lot of pop-ups, but that in itself is not a problem since i did put all the security settings to high.

The problem i'm having is that the pop-ups stay on screen and on-top of every other windows, for what seems an eternity, after i've clicked allow, now that is very annoying.

Also, this is a firewall and yet in all those pop-ups, i have yet to see the mention of a protocol, a url, an IP, a port or anything related to networking. Does that mean any program that i "allow" to run gets full network and internet access?

btw, i'm on Win XP if that makes a difference.

The kind of information you require can be found by clicking 'details' which is next to the 'options' button on the pop up.

See pages 12 & 16 in the PF guide, links in MC's post.

mmm ... now that's weird. I just opened Skype (that always gets me 2 pop-ups or more) and nowhere on the pop-ups can i see either "options" or "details". The only buttons are "Allow", "Train", "Terminate" and "Block".

I even removed Skype from the rules and yet all the pop-ups (much more numerous) i got had only the same 4 buttons.

I get four choices on both the firewall alerts and the process monitor alerts, 3 buttons (Allow, Block, Options) and a 'Details' link. I've only just started using it myself so I'm not sure I can help further, I just thought I would post about pages 12 & 16 (see also p23) as I had just been reading them in the manual. The manual is 62 pages long so you might find a reason in there why its not working for you.

I'm using PF on Windows 8 pro 64-bit so this is a difference but PF should support XP as well.

It's also worth noting that with most firewalls of this type, the nature, number and options possible from alerts will vary depending on how the initial configuration has been setup. Again, it is necessary to read the documentation thoroughly first and then decide which are the best options for your own requirements. MC - Site Manager.
Using any type of firewall with HIPS capability requires an understanding of how this operates and how to respond to alerts. Users should read the vendors documentation before installing the software to avoid setting rules that could be leave their system vulnerable. The PDF guide for Privatefirewall is located on this page. MC - Site Manager. Further reading.

I haven't read the documentation, but the pop-ups are clear enough.

You seem to have completely missed the point of my comment.

What i expect of a firewall is to be asked what program should have access to the network and the internet, trough what protocol (TCPIP, UDP, ...), to make outbound or accept inbound connections, from what URLs or IPs. That's the firewall's job. A firewall that's always asking about temp files created by portable software is more annoying then helpful.

The HIPS i need is to know what program is using svchost to access the internet or using firefox.

Do the Basic Firewalls offer that kind of control?

Sorry, but my reply was completely relevant, hence my suggestion to research these things before installing the software concerned. You are asking about firewall functions and yet commenting about process monitor alerts which are completely separate issues. HIPS related components and alerts are notoriously difficult to understand unless you have an advanced knowledge of Windows processes. In this respect, such users are better off employing safe surfing practices and using a pure firewall. With XP this is not a problem as you can run one of several excellent free firewalls that no longer function beyond XP or Vista. My own recommendations would be either Kerio 2.1.5 or Sygate. MC - Site Manager. You will need to Google around for Kerio and choose your own download source.

I was browsing around on Softpedia. And I discovered a rather interesting, um case of TWINS.

Here is the link to the screenshots of PrivateFirewall:


Now, check the screenshots for an older firewall called
Webroot Desktop Firewall:

Gee, I believe that when Webroot "disappeared", it became PriveateFirewall, either that or it is a clear case of copying.

Just thought I'd share that with the nice people here.

BTW, I have used PrivateFirewall in the past, excellent package. A wee bit too "chatty", or maybe that would be "naggy"?

Privatefirewall is the original code. Webroot licensed this technology for use in their own products. MC - Site Manager.

Since today's version of "ZoneAlarm Free" you can't install without checking the 2 following boxes ...

"Set Zonealarm Search as my default search provider for : Firefox"
"Set Zonealarm Search as my home page and new tab for : Firefox"


Anybody knows a good alternative with user rules ?
With user rules i mean you'll get a popup where you can decide to block or allow a program to send data to interenet.

Greets , Kuoi

I thought the same thing was happening as well, but it turns out you can install ZoneAlarm Free without changing your default search, home page, new tab or adding a toolbar. First of all, select Custom Install rather than Quick Install. Now on the next screen on the bottom left hand corner you should see "ignore all offers" - look closely, because they HIDE this option in a light blue text on the dark blue background (pretty sneaky...) This bypasses the popup screen that prompts you to check those boxes and installs it without making the changes.

I don't know why they're making this so difficult (I tried to have my sister install ZoneAlarm Free on a XP-based system that she got from a friend and didn't know about this, do I had her turn on the Windows XP firewall instead...) Having to search for a way to avoid making these kinds of changes to your browser's configuration isn't the most effective way to promote a product...

... but there is only 1 BIG button you can click on in the first window
"QUICK INSTALL : install with default settings"

... and I don't want to push that button because I don't want their browser hyjack !!!

You can try "Windows 7 Firewall Control": easy-to-use and effective! You can run it with native Windows Firewall on - so you don't need to disable in-built firewall.

You can opt out of these changes, or change them back after install. No one can help you with an alternative unless you tell us which operating system you have. MC - Site Manager.

MidnightCowboy: I'm seeing the same thing as Kuoi. The latest ZA upgrade only offers a Quick Install option; the Custom Install option has been removed. Maybe those choices show up later in the installation, but when I chatted with ZA tech support I was told that this is the new normal -- you cannot set or override the defaults during an upgrade. The tech said I'd have to completely remove ZA and reinstall to get the custom install option. I can back up my security settings, but would have to manually undo the changes they make to my search engine and home page. I'm going to stay with the current version of ZA.

Well, the OP did say install and not upgrade. Even so, most would regard this as a minor inconvenience considering the changes are so easily reversed and certainly no reason to move to a different firewall. MC - Site Manager.