How to Check If a Website Is Down: 7 Technical Reasons and How to Investigate Them

At the time of writing this, Amazon’s AWS experienced a massive outage in their US-East-1 region, disrupting everyday life worldwide. Flights were delayed, banking systems went offline, and games froze. When this happens, users rush to sites like DownDetector to check if a website is down or if the issue is affecting others globally.

For the average person, it’s a quick sanity check: “Is it just me, or is everyone else having this problem too?”
But for cybersecurity professionals, OSINT analysts, or SOC teams, knowing how to check if a website is down — and more importantly, why — is far more complex.

This guide explains how to check if a website is down using technical methods, distinguish between types of downtime, and interpret the underlying signs that reveal the real cause of an outage.

1. Is It DNS?

The first step in any website outage investigation is to check the DNS records. Using a tool like digwebinterface.com, query the domain’s authoritative nameservers for A, AAAA, or CNAME records.

If you get no answer or an NXDOMAIN response, the issue is at the DNS level — not the server itself.

Quick checks:

• Websites: Verify A (IPv4), AAAA (IPv6), and CNAME records exist and resolve correctly.
• Email: Confirm MX records and their priorities.
• No records at all: The zone may be misconfigured or deleted intentionally.

Bad actors sometimes delete DNS records temporarily after abuse reports to make a domain appear “clean.” Once a registrar closes the case, they restore the records, reviving the malicious site.

If DNS is missing but the IP is still active, the infrastructure often still exists — only the resolution layer is “down.”

For more on DNS best practices, see ICANN’s DNS Security Guidelines.

2. Did It Get Held? (clientHold / serverHold)

Sometimes a domain doesn’t just vanish because of broken DNS — it’s deliberately suspended.

Registrars can place a clientHold, while registries can apply a serverHold. Both prevent global DNS resolution.

• clientHold: Set by registrars for non-payment, legal issues, or confirmed abuse.
• serverHold: Set by registries for severe policy or security violations. Only the registry can lift it.

These statuses render the domain inert — registered, but non-functional. You can check this in a WHOIS or RDAP record under Domain Status.

For deeper insight, refer to ICANN’s Domain Status Codes Reference.

3. 401 Unauthorized

A 401 Unauthorized means your browser reached the web server, but access is restricted.

Interpretation:

• The web server is live, but the resource requires authentication.
• The site owner or threat actor might temporarily hide pages to evade detection.

If the homepage returns a 401, it may be a misconfiguration or network restriction — not a true outage.

4. 404 Not Found

The well-known 404 Not Found means the web server is up, but the requested content is missing.

Common causes:

• URL typo or outdated link.
• Deleted or moved content without a redirect.
• Misconfigured routing or web application setup.

If the root domain (e.g., example.com) still loads, only a specific path is broken. If even that fails, the server may be running without content deployment.

For more detail on proper 404 handling, see Cloudflare’s 404 Troubleshooting Guide.

5. 503 Service Unavailable / 504 Gateway Timeout

When DNS works but the page returns a 503 or 504, the issue is deeper — typically within the web server or an upstream connection.

• 503 Service Unavailable: The server is overloaded or under maintenance.
• 504 Gateway Timeout: A proxy or load balancer (like Cloudflare) can’t reach the origin server.

Investigative clues:

• Cloudflare-branded 5xx pages mean the proxy works but the origin is unreachable.
• If multiple domains on the same IP show similar issues, the host might be suspended or offline.

These server-side failures often distinguish temporary outages from deliberate takedowns.

6. Temporary DNS Glitch vs. Intentional Deletion

DNS outages can occur due to TTL expiration, propagation delays, or deliberate record removal.
When patterns show certain records disappearing (like A or MX) while NS and SOA persist, it’s often an intentional deletion — a tactic used to hide malicious infrastructure temporarily.

SOC teams can track these changes using passive DNS tools or internal monitoring systems, correlating patterns across campaigns.

7. Hosting Suspension or Account Termination

If multiple domains on the same IP suddenly go offline, it’s likely due to hosting suspension for non-payment, policy violation, or abuse reports.

Persistent 5xx errors or blank responses often indicate account-level actions by the provider.
Cross-referencing IP data via tools like Shodan can confirm the hosting environment and reveal broader disruptions.

For guidance, see Cloudflare’s Origin Server Error Documentation.

Conclusion

Learning how to check if a website is down is rarely as simple as confirming whether it loads or not. Understanding if the outage stems from DNS failures, registrar or registry holds, HTTP authentication issues, or server-side errors helps determine the real cause behind the disruption.

For SOC teams, CISOs, and IT professionals, mastering how to check if a website is down accurately is essential for:

• Effective threat attribution and abuse mitigation
• Prioritizing incident response efforts
• Strengthening infrastructure resilience and continuity planning

Knowing how to check if a website is down from multiple technical angles ensures faster diagnostics, smarter mitigation, and a clearer view of an organization’s online stability.

Learn more about related topics on phishfort.com, including:

• Domain Takedown Procedures
• Threat Infrastructure Analysis
• Domains Takedowns

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Table of Contents

1. Is It DNS?
2. Did It Get Held? (clientHold / serverHold)
3. 401 Unauthorized
4. 404 Not Found
5. 503 Service Unavailable / 504 Gateway Timeout
6. Temporary DNS Glitch vs. Intentional Deletion
7. Hosting Suspension or Account Termination
8. Conclusion