Why Is My Firewall | Blocking Everything [verified]

Then I checked the audit log. Timestamps from 3:17 AM. Every two seconds, an entry: “Filtering platform policy change.” And then, at 3:18 AM: “Windows Filtering Platform base filtering engine stopped.” Restarted at 3:19 AM with a new configuration. The configuration had exactly one rule:

Your firewall isn't the problem—it’s likely your ISP, your router hardware, or a DNS failure.

Sometimes it isn't the software on your computer, but the firewall on your .

If you've made many changes and can't find the culprit, use the "Restore Defaults" option in your firewall settings to clear out all rules and start fresh. : why is my firewall blocking everything

You’d think a firewall is a simple thing: it says “yes” or “no.” But mine had started screaming “no” at everything—my browser, my email, even the little widget that checks for system updates. Every few seconds, a fresh alert popped up in the corner of my screen: “Firewall blocked connection to 192.168.1.1.” Then: “Firewall blocked svchost.exe.” Then: “Firewall blocked Windows Explorer.” Yes. It had blocked Explorer. I couldn’t see my own files anymore. The desktop was a static photograph.

When two firewalls try to manage the same traffic ports simultaneously, they can create a "deadlock" where neither allows the packet through because the other is inspecting it.

Firewalls work based on a "Rule List"—a set of instructions that says "Allow Chrome, Block Malware." Then I checked the audit log

If your VPN crashes or the "Kill Switch" is engaged, the VPN software will intentionally block all internet traffic to prevent your real IP address from leaking.

This often happens when a user installs a new third-party firewall or security suite. During installation, the software may ask if the user wants to "Lock down" the system. If the user selects the highest security setting without realizing the consequences, the firewall effectively builds a fortress with no doors. It isn't that the firewall is broken; it is simply adhering to a "better safe than sorry" philosophy to an extreme degree, lacking the "allow" rules required for normal web browsing.

Sometimes, the issue is not with the firewall's settings, but with the presence of too many security layers. Many users install a third-party antivirus or firewall on top of the one already built into their operating system. When two firewalls run simultaneously, they can conflict with one another. One firewall might allow a connection, while the other intercepts and blocks it, or they may essentially create a "rule collision" that results in total connectivity loss. The computer becomes a battlefield where the combatants are your security programs, and the casualty is your internet connection. The configuration had exactly one rule: Your firewall

Firewalls and security certificates (HTTPS) rely heavily on timestamps. If your computer thinks it’s 2015, the firewall will flag all incoming web traffic as "expired" or suspicious and block it instantly.

If you have a third-party antivirus (like Norton, McAfee, or Bitdefender) and you also have Windows Defender active, they might be tripping over each other.

I rebooted into safe mode, disabled the firewall, and the internet roared back to life. So the problem wasn’t the network. It was the firewall itself. But why? I hadn’t changed any rules. I hadn’t installed new security software. It was the same basic Windows Defender Firewall I’d ignored for three years.