Security Policy Errors

How to Safely Test If Your Firewall Is Working on Windows

Ayan Masood Oct 22, 2026 869 views

Question details

The user wants to safely verify that their network firewall is active and correctly blocking unauthorized inbound connections without disrupting outbound internet access.

How to Safely Test Whether a Firewall Is Working

Product: Windows Firewall
Device & OS: Windows
Scenario: Verifying local and network security configurations to ensure protection against unauthorized external access.
Observed behavior: The firewall should block unsolicited inbound network requests while allowing normal outbound connections like web browsing to continue working.

Before you start

Ensure you are connected to the specific network you are authorized to test (such as your home or private office network) rather than a public Wi-Fi hotspot.

Solution 1Recommended

Use the GRC ShieldsUP Online Testing Service

ShieldsUP is a reputable, web-based tool designed to safely probe your network for exposed inbound ports.

By simulating standard external requests, this service allows you to see exactly what a malicious script or hacker would see when scanning your IP address. A properly functioning firewall will show ports as "Stealth" or "Closed".

Access ShieldsUP

Open your web browser and navigate to the Gibson Research Corporation testing page at https://www.grc.com/x/ne.dll?bh0bkyd2.

Authorize the scan

Read the standard testing agreement and click on the 'Proceed' button to confirm you are authorized to test the current IP address.

Run a common ports test

Click on 'Common Ports' or 'All Service Ports' from the testing menu to initiate a safe, read-only scan of your inbound network connections.

Review the results

Wait for the scan to complete and verify that your ports are listed as 'Stealth' or 'Closed', which confirms your firewall is successfully blocking unsolicited traffic.

Understanding Stealth Ports: A 'Stealth' status means your firewall is completely ignoring unsolicited inbound requests, making your computer effectively invisible to automated network scanners on the internet.

Solution 2

Verify Windows Defender Firewall Settings

Check your local Windows settings to ensure the built-in firewall is enabled and enforcing its default blocking rules.

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Ensure Secure Document Management with WPS Office

While keeping your system secure with a properly configured firewall, you also need a productivity suite that respects your privacy. WPS Office is a fast, lightweight alternative to Microsoft Office that works flawlessly offline and behaves predictably behind strict network firewalls.

1. Download the installer: Visit the official WPS Office website and download the setup file for Windows.
2. Run the setup: Open the installer and follow the on-screen prompts. Your Windows Firewall may ask you to allow network access for optional cloud features.
3. Start working securely: Open WPS Office and begin creating or editing your documents locally in a secure environment.

Operates smoothly offline behind strict system firewalls without unauthorized background connectionsFully compatible with Microsoft Word, Excel, and PowerPoint document formatsLightweight installation with a familiar, easy-to-use user interfaceCompletely free basic functionality for everyday office tasks

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Frequently Asked Questions

Is it safe to use online firewall testing tools?

Yes, using reputable services like GRC ShieldsUP is completely safe provided you are testing a network you own or are authorized to test. These tools simply simulate standard external connection attempts to see if your firewall stealths or blocks them, without delivering any malicious payloads.

Will testing my firewall disrupt my internet connection?

No. Standard inbound port testing checks for blocks on incoming requests and will not affect your normal outbound internet access, active downloads, or video streaming.

Why might a port show as 'open' during a firewall test?

An open port indicates that an application or service on your network is actively listening for incoming connections, and your firewall or router is configured to allow it. This could be intentional (like running a personal web server) or it may pose a security risk if left open unintentionally.

Does my router act as a firewall?

Yes, most modern home routers feature built-in Network Address Translation (NAT) and SPI firewalls. When you run an online test, you are primarily testing your router's firewall rather than your computer's local software firewall, unless your computer is connected directly to the modem.

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