There's no way to know for sure whether the best things in life are free, but extensive expert testing shows that the best firewall software is. Although it doesn't cost anything, Comodo Firewall easily handles all of the challenges thrown its way, including a perfect run in Matousec.com's stringent testing. It performs equally well in leak tests, and critics say they appreciate Comodo's sandbox mode, which limits the functionality of questionable programs until their safety is determined. Some reviewers dislike how Comodo prompts users to make most of the security decisions about whether to allow specific programs to run, a complaint that carries over to warnings from Comodo's Defense+ behavioral analysis. Users, for the most part, don't find it as annoying as the professionals and say that the prompts virtually disappear after you train the firewall.
Older versions of Comodo Firewall had a notoriously long and irritating installation process, but the newest builds are more streamlined and quick to set up. Once Comodo Firewall is up and running, experts say the impact on system performance is minimal. Tech support for the free software is limited to an online forum and an email-based ticket system. If you're interested in a more complete security solution, the similarly free Comodo Internet Security bundles Comodo Firewall with Comodo Antivirus, but experts say its malware-fighting capabilities are limited. Reviews say that Kaspersky Internet Security 2012 (*Est. $80) protects computers more effectively all-around.
Two top-notch professional review sources examine Comodo Firewall in-depth: Matousec.com and PCMag.com. PC World and Gizmo's Freeware also provide detailed write-ups of the software, although PC World looks at an older build. Finally, hundreds of users at Download.com, Softpedia.com and FileForum.com provide hands-on reports from the field.
Matousec.com provides thorough and current efficiency results for a vast number of firewall applications. Comodo Internet Security -- which includes Comodo Firewall -- is the only product to receive a perfect score in the older Proactive Security Challenge. It is also the only firewall to receive an Excellent (or even Recommended) rating in the newer Proactive Security Challenge 64 test, although only a handful of firewalls are subjected to the test. However, issues such as user friendliness and the effectiveness of other components in the suite are not addressed in either test.
Review: Proactive Security Challenge, David Matousek
PCMag.com examines the newest major version of Comodo Firewall in this multipage review. Neil J. Rubenking conducts extensive testing and finds the program effective, but he dislikes how Comodo and its Defense+ behavioral protection forces users to decide whether to allow a program to run. "Webroot has shown that behavior-based detection need not hassle the user; Comodo should learn that lesson," he writes.
Review: Comodo Firewall 5, Neil J. Rubenking, Jan. 19, 2012
3. PC World
Preston Gralla reviews an older version of Comodo Firewall and gives it high marks for efficiency, although he says Defense+ can be annoying. He notes, however, that you can turn that feature off if you don't like it. Gralla's complaints about installation hassles have been addressed in newer versions of Comodo Firewall.
Review: Comodo Firewall Is a Superb Security Program (If You Ignore Its Bundled Software), Preston Gralla, Feb. 10, 2010
4. Gizmo's Freeware
While the editors of Gizmo's Freeware don't lay out their testing criteria, they do an excellent job of highlighting the pros and cons in firewall software thanks to their in-depth discussions and descriptions. Comodo Firewall receives a heap of praise and the highest overall rating, with only a few minor negatives listed.
Review: Best Free Firewall, Editors of Gizmo's Freeware, Updated Feb. 17, 2012
Download.com's editors remain mum about Comodo Firewall, but a large number of users report experiences that overall are pretty positive. Reviews of the current version are limited, but users are largely impressed. One found the program used excessive CPU cycles, however.
Review: Comodo Firewall, Contributors to Download.com
Comodo Firewall enjoys a sterling reputation at Softpedia.com. The editors' give the program a 5-star rating, and user ratings are nearly as pristine, with Comodo carrying a 4.5-star overall rating from 1,500 users, though these reviews span past versions as well as the current version of the firewall. Dozens of users also leave written reviews of the software.
Review: Comodo Firewall 5.9.23255.2196, Contributors to Softpedia.com
Users at FileForum.com are just as pleased with Comodo Firewall, although their numbers are fewer than the ones at the other sources. Comodo Firewall carries a high average rating, but few contributors bother to leave a written review.
Review: Comodo Firewall, Contributors to FileForum.com