Signs Your Firewall is About to Fail and How to Avoid It
I’ve been at this long enough to witness every firewall failure scenario possible—subtle misconfigurations, aging hardware slowly wheezing, you name it; I’ve seen it, including a total meltdown. And can I tell you, it’s uncanny how you know when to see the warning signs before disaster strikes? That the difference between a minor inconvenience and a full-blown breach.
Firewalls are the key component of modern cybersecurity, but far too many businesses treat them like a set it and forget it appliance. Big mistake. A breaking firewall won’t always be instantly visible — sometimes it’s an agreement of slow decay until bam, all of a pointed it’s wide open and attackers can waltz right in.
Let’s discuss how to perceive the cracks before they break.
Common Failure Symptoms
The early warning signs I see right before a firewall goes from everything is nice to why is our network down?
1. Sluggish Network Performance
If your internet is as slow as an old-school 1999 dial-up modem, your firewall may be the choking point.
- Packet loss
- Latency spikes
- Random disconnects
Packets are processed forever by the firewalls. If they’re overloaded (especially on older systems, or underpowered ones)—you’ll sense it in slow application response times.
2. Firewall Crashes or Reboots Frequently
Your firewall KEEPS rebooting/crashing, it’s saying, it’s trying to tell you, no, I need help, help me. And then: Hardware failure, software bugs, overheating—it could be anything.
- Unexpected reboots
- Frequent process crashes logs
- Fans at full speed 24/7 (yes, I listen to this during onsite checks)
I used to work with one financial firm where the firewall would periodically reboot on its own. It turned out their server closet had been overheating for months. The firewall was literally cooking itself to death.
3. The logs are empty — or too full
Check your firewall logs (you’re checking those, right?).
- No logs? Nothing’s being recorded. Logging is either turned off, or the system itself is failing.
- Too many logs? Nonstop alerts? That’s evidence of misconfigurations, attack attempts, or resource exhaustion.
I saw an enterprise firewall producing 5GB of logs an hour — it had been under perpetual brute-force attack for weeks, no one was paying attention.
4. Old Firmware (No One Worked on Patching)
Essentially, old firmware is an open invitation to attackers. If your firewall hasn’t had a patch in a year, you’re gambling with fire. Zero-day exploits have no regard for your IT budget.
Sorry — if your firewall has 2017 firmware, AI security tools won’t help you.
5. Strange Network Behavior
This is where it starts getting strange.
- Unexplained traffic spikes—no specific cause
- DHCP issues where devices do not obtain right assignments
- VPNs disconnecting randomly
Often, when a firewall fails, it goes into some crazy state before it dies completely. Disregarding it = courting disaster.
How to Monitor Firewall Health
Ties During Security We like to be informed, not surprised. Here are ways to catch those early warning signs before it goes south.
- Monitor Logs Weekly – Checking logs for 5 minutes can help catch anomalies.
- Track CPU & Memory Usage – Spikes in usage are usually a sign that failure is imminent.
- Check Rule Base Regularly: Too many rules can silt even a top-end firewall.
- External Scans — Have a third-party vulnerability scan to capture gaps missed by internal tools
- Test Failover systems – If you have an HA firewall failover system, make sure it really works.
I’ve been called in too many times to support a high availability setup that was anything but high availability.
Maintenance Strategies to Avoid Firewall Health Issues
It is where good IT maintenance can help in ensuring firewalls in place do not fail instead of simply waiting for them to fail.
1. The firmware should always be kept up to date (no ifs, ands, or buts!).
Firmware updates — Quarterly schedule We’ll do it later — because later generally means never.
2. Apply Best Practices for Management of Rules
Rule sets with many entries slow down firewalls and lead to misconfigurations. Clean them up:
- Flush out rules that are old, unused and no longer needed
- Merge duplicate rules to eliminate expensive processing.
- Log separate crime rules for the notifications of unauthorized change
3. Monitor Hardware Health Like Your Business Depends on It (Because It Does)
- Check fan speeds and temps Heat kills firewalls.
- Preemptively replace aging hardware before it becomes a liability.
- Ensure stress tests at least quarterly—identify vulnerabilities before an attacker.
Not so long ago, I assisted one major bank in migrating to zero-trust architecture. You wouldn’t believe what kind of ancient firewall hardware we found along the way — things that should’ve been decommissioned decades ago.
4. Attempt Failover & Redundancy Programs
We don’t think about failover until we need it. Make sure:
- Standby firewalls can assume control immediately.
- Redundant internet connections work (really).
- The failover mechanism has been documented and tested.
You’d be surprised how many times I’ve heard: Oh, we have a backup … we just haven’t tested it.
5. Implement Access Control & Least Privilege
- Restrict who may update firewall rules.
- Use multi-factor authentication to get into stuff.
- Log all admin actions — so there are no undocumented changes.
I still remember when passwords were something you wrote on a sticky note next to the server rack—thank goodness we’re past that (mostly).
Health Checks on PJ Networks’ Firewalls
Here’s what we do at PJ Networks when clients hire us to examine their firewalls:
Step 1: Perform a Complete Configuration Audit
We look for dangerous rules, vulnerable configurations, and weak policies.
Step 2: Performance Testing and Load Analysis
- Emulate real-world attack traffic
- Measure processing latency
- Identify bottlenecks
Stage 3: Patch & Hardening Plan
- Apply necessary patches
- Eliminate legacy cryptography protocols
- Comply with the new cybersecurity standards
Step 4: Testing Failover & Incident Response
Telling someone that the firewall should have kicked in is not an excuse which is good enough when your network collapses.
We’ve done it for banks, for hospitals, for enterprises — and believe me, every company has something that could be better.
Conclusion
You rely on your firewall to protect your network—but once it fails, all bets are off.
Here’s the thing: firewall breaches don’t occur overnight. The symptoms are present weeks — sometimes months — ahead of the final collapse. Overlooking them, therefore, is a monumental blunder.
So you haven’t looked at the health of your firewall lately? Do it today. Before you’re made to reckon with an outage — or, worse, a breach.
And if you want a real security check (not your old “it’s plugged in and seems ok”), talk to my team. I’ve saved more companies from costly downtime and security catastrophes than I can count.
Nothing says Monday Morning like a compromised firewall.