Making the invisible visible: Are your cloud firewalls and DDoS protection really working?

Every business builds strong defences to keep attackers out. Firewalls and DDoS protection serve that purpose, standing guard over company apps and websites, like knights at the castle gate keeping out trolls (not just the ones on X).  

But here’s the problem: those defences only work if users actually walk through the front gate. Sometimes, people find hidden paths or side doors around your walls, so the guards never see them enter. If you don’t watch the roads and know which way users came in, your castle isn’t truly protected.  

It’s exactly the same thing with the Internet. Firewalls and DDoS protections only work if real user traffic flows through them, especially traffic from last-mile ISPs, broadband providers, and mobile networks.

Most enterprises can’t answer the critical question: “Are real user queries actually flowing through the cloud firewall, and how does protection impact performance across the global internet?”

That’s the visibility gap. It’s the blind spot at the heart of digital defense, whether for legacy apps, SaaS platforms, or today’s AI/LLM-driven services. And until you close it, you’re never fully certain that your security posture matches the real user experience.

The real-world visibility gap

End users never access platforms from inside cloud regions. They connect via their local ISPs, broadband providers, and mobile networks.  

That creates big blind spots:

• You might think DDoS mitigation kicked in when, in fact, it didn’t.

• Traffic could silently drift, bypassing your cloud firewall altogether.

• Activating scrubbing centers could introduce unexpected latency that goes unnoticed until customers start complaining.

Cloud-based monitoring alone can’t spot these shifts. It only shows what’s happening inside cloud data centers, not the messy open roads where your users really travel.

Why the right monitoring matters

It’s not enough to ask, “Did I configure the firewall?” The real question is, “Can I prove that my users’ traffic is actively protected, no matter where it originates?”

Observing traffic at the Internet’s edge, from local ISPs to backbone transit, enables teams to detect critical security events as they occur:

• When a DDoS mitigation ASN appears or disappears along the network path.

• When traffic is rerouted away from security controls because of BGP or DNS drift.

• When performance shifts dramatically following the activation of scrubbing centers.

This edge visibility is what turns assumptions into facts.

How do you monitor firewall and DDoS flows?

Organizations that take resilience seriously don’t stop at cloud-region monitoring. They combine cloud and data center controls with edge and path-level visibility that makes the invisible visible.  

The most valuable strategies include:

• Hop-by-hop path analysis: Track IP addresses, ASNs, latency, and packet loss to pinpoint precise route divergences-not just at the origin but as traffic transits the wild edge of the internet.

• BGP route monitoring: Detect if and when your network prefixes are advertised by mitigation partners or taken over by unexpected routes.

• Synthetic testing from last-mile ISPs: Measure availability, latency, and overall user experience both in protected and unprotected scenarios, ensuring global coverage-not just cloud-region monitoring.

• ASN-driven alerting: Get notified instantly if security checkpoints vanish from the path or if new, unexpected networks show up.

What about different mitigation models?

Visibility is essential no matter how your defences are designed:

• Always-On models maintain continuous routing of all traffic through scrubbing centers for zero-second failover and stringent SLAs but can add constant inspection overhead.

• On-Demand models only engage mitigation on attack triggers, reducing normal latency but risking brief outages due to failover timing.

• Hybrid models strike a balance-critical apps/resources remain protected at all times while others shift to protection as needed.

If you’re not monitoring flows themselves, you can’t know whether these models perform as promised, or whether hidden gaps are quietly undermining your security posture.

Why does this matter now?

The risks are high in every sector:

• In e-commerce, if your online store lags during a sale, you lose customers.

• In finance, a simple policy change can reroute traffic around firewalls-leaving essential filters bypassed.

• If a SaaS tool drops connections in Asia or anywhere else, the problem may go unnoticed for hours without last-mile monitoring.

Simply deploying security controls is no longer enough. The only way to ensure resilience, accountability, and true protection is by making Internet “blind spots” visible, tracking flows end-to-end from the edge to the cloud, across every ISP and every path.

How does Catchpoint close the gap?

Catchpoint’s Internet Performance Monitoring (IPM) platform enables you to see the full journey step by step, from the edge of the Internet through every security checkpoint. It works for all digital services, including websites, apps, and AI chatbots powered by large language models (LLMs).  

This monitoring approach enables organizations to address use cases such as:  

• Validating global service availability

• Measuring performance impact with and without cloud firewalls

• Providing independent confirmation for auditors

• Detecting outages and latency changes in real time

• Correlating user experience with network security events

• Monitoring end-to-end dependencies (including CDN, DNS, API, Cloud, and AI/LLM services)

• Conducting post-attack forensics and ensuring SLA compliance

• Confirming mitigation effectiveness and successful recovery

• Integrating with DDoS playbooks and automated alerting systems

Wrapping it up

To keep your business truly safe, don’t just build strong walls. Make sure you know which path everyone takes to your front door. The only way to really secure your castle is by watching the roads, validating the journey, and responding fast when anything goes wrong. Visibility is what turns security from hope to certainty.  

Next steps

• Want to see how this works in practice? Start a 14-day free trial and monitor your own firewall and DDoS flows from the edge of the Internet.

• For a broader look at how enterprises are building resilience, download the Internet Resilience Report 2025.

• Learn more about this challenge in our blog: Cloud monitoring’s blind spot-the user perspective.

‍