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DIY Cybersecurity Firewall Test

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Solos and small firms typically rely on the firewall built into the router supplied by their Internet service providers. Home computer users do, too. Alternatively, a local IT company may supply and manage a separate hardware firewall for you.

In either case, you are well-advised to test your firewall or have your IT company test it for you.

You can perform a free, basic test yourself at

Heads Up: Don’t run the GRC test without touching base with your IT provider if they monitor your systems for possible attacks.

Steve Gibson, the owner of, has a long track record in the field of cybersecurity. offers a free test called ShieldsUp. The test looks for common security holes in the firewall that protects your computers and other devices that use your Internet connection. It will test your router’s firewall or, if you have one, your hardware firewall.

Be aware that the ShieldsUp test will probe your firewall from the GRC computers (IP range: through If your firewall generates logs, they will record the ShieldsUp testing.

Also know that, cosmetically, the website is ugly and dated. That is not a reflection of low-quality services. Rather, Gibson focuses on all things cybersecurity. He does not devote time to making the website look pretty or modern.

To run the ShieldsUp! test (after notifying your IT support people):

  1. Go to 
    (Yes, that page name looks weird, but it works and GRC is trustworthy!)
  2. Press the Proceed button (but only after reading the “Please take just a moment . . .” information).
  3. Wait a moment for the next page to load.
  4. Scroll down and click the File Sharing test link under ShieldsUp! Services
  5. Also run the Common Ports test by clicking its link.

Don’t panic if your system fails the Common Ports test. Most firewalls will fail because of the Ping Reply test. That is no cause for significant concern.

If your test results are stamped FAILED in red:

  • Look for a third paragraph below the FAILED stamp.
  • If it starts with Ping Reply: RECEIVED (FAILED):
    • It means that hackers can see that your device IS connected to the Internet.
    • It is not a sign that you have a security hole.
    • But because your device can be “seen,” it is a potential target for an attack.

The Ping Reply feature can be blocked. Then malicious bots surfing the web won’t see your system as a potential target. You could change the Ping Request setting on your router or have it changed for you.

The more important test results are under the Status heading in the results table below the initial paragraphs. It is important that these are all green and say “Stealth.” Security Test

Did your firewall pass the test?

If so, good, but don’t rest on your laurels. The ShieldsUp tests are accurate but don’t guarantee your cyber safety. Criminals have other ways of getting in.

At a minimum, everyone needs:

  • Modern antivirus software
  • Cybersecurity training, including: Don’t click on that tempting link!
  • Offsite or cloud backups safe from hackers

Another important defense is a service that monitors your computers for new, sophisticated breaches that made it through your other defenses. Refer to the Gartner Managed Detection and Response (MDR) Services Reviews and Ratings. Full disclosure: my company offers the Huntress service for solos and small firms at a cost well below the field.

Hiring a company to do a cybersecurity audit and penetration testing each year sharply reduces your exposure to cybercrime. If your local IT provider does not provide these services or have a recommendation, a couple of companies you might look to are:

CyberHunter Solutions, Toronto
HackerOne, San Francisco

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