Overview 💥
The “Unknown error while running execSync” message in the Internet Domain/DNS Inspector typically indicates that Liongard was unable to successfully execute DNS queries for the domain being inspected.
This issue is almost always caused by invalid domains, expired registrations, DNS resolution failures, or connectivity issues on the Inspector host.
This article provides a detailed breakdown of why the error occurs, how to diagnose it, and step-by-step remediation guidance, including using Liongard’s Clear Cache + Debug Mode (CCDM) for deeper validation.
Why This Happens 🤔
This error occurs when Liongard’s Inspector cannot execute DNS queries or resolve the domain using system-level tools.
Common underlying causes include:
❌ Domain does not exist, is expired, or is incorrectly typed
🌐 Domain is not publicly resolvable (private/internal domain)
🚫 DNS resolution blocked by firewall, proxy, or local policy
🧱 Network-level restrictions preventing outbound DNS/HTTP lookups
🔄 Caching issues that Clear Cache + Debug Mode can resolve
📝 Registrar issues such as parked domains or ISP landing pages
🛑 Inspector host misconfiguration (DNS servers, connectivity issues)
Steps to Resolve 👨💻
Step 1️⃣ — Verify the Domain Exists and Is Public
Open the Inspector → check the domain value configured.
Navigate to the domain in a browser:
If it loads normally → proceed.
If it shows an ISP parking page, 404, or fails to load → fix the domain or resolve with the registrar first.
Confirm the domain is public, not internal (e.g.,
.local,.lan,.corp).
Step 2️⃣ — Verify DNS Resolution (dig / nslookup)
Run the following from the Inspector host or any diagnostic system:
Linux/macOS:
dig <domain> nslookup <domain>
Windows:
nslookup <domain>
If resolution fails or times out → DNS configuration or registrar-side issue.
Step 3️⃣ — Verify Registration Status (WHOIS)
Run a WHOIS lookup via command-line or online tools:
Check for:
Expired domains
Recently transferred domains
Registrar hold or pending verification
Incorrect or missing nameservers
Step 4️⃣ — Check Network & Firewall Access
Ensure the Inspector host can reach:
Port 53 (DNS)
Port 80/443 (HTTP/HTTPS)
Try:
ping <domain> curl -I <domain>
If blocked → update firewall allow rules.
Step 5️⃣ — Review Inspector Logs
In Liongard:
Go to the Inspector
Select Logs
Look for:
“DNS resolution failed”“execSync timeout”“host unreachable”“permission denied”“Bad domain format”
This helps narrow the cause.
Step 6️⃣ — Run Inspection in Clear Cache + Debug Mode
This forces the inspector to bypass cached DNS responses and re-process data end-to-end. This also produces enhanced logs that help diagnose root causes.
Step 7️⃣ — Validate DNS Configuration Using External Tools
You may use a external DNS testing tools to verify whether the updated DNS records have fully propagated across the internet. This helps determine if inconsistencies are due to slow propagation, cache delays, or incorrect DNS configuration.
What to do:
Open any of the following DNS testing tools:
Enter the domain you are troubleshooting (e.g.,
example.com).Run the lookup.
Compare results to:
Registrar records
dig/nslookup
Liongard Inspector results
If external tools fail → global DNS issue
If external tools succeed but Liongard fails → caching or Inspector host issue → run CCDM again and check host DNS settings.
Troubleshooting Table 🤩
Check Category | What to Verify | How to Test | What Success Looks Like | What Failure Indicates |
1. Domain Status | Domain exists, active, and publicly reachable | Run a WHOIS lookup | Active status, valid registration dates | Domain expired, suspended, or not registered |
2. Basic Reachability | Website or domain resolves in a browser | Navigate to the domain in any browser | Site loads normally | ISP parking page, 404, or server unreachable |
3. DNS Resolution | DNS records return accurate results | Run | DNS resolves to valid IPs | DNS unavailable, misconfigured, or NXDOMAIN |
4. DNS Propagation / External Validation | DNS records match across global resolvers | Use any external tool | Consistent values across providers | Propagation delay, stale DNS, or regional mismatches |
5. Proxy Configuration | Proxy settings (if used) are correct | Validate system proxy or Inspector proxy settings | Inspector connects through proxy without error | Misconfigured or authentication-required proxy |
6. Inspector Logs Review | Look for specific error messages | View Liongard Inspector logs related to DNS/execSync | Logs show successful resolution or clear info | Errors like timeout, ENOTFOUND, or blocked requests |
Additional Resources 🚀
Contact Liongard Support 🦁
Open a ticket if:
Clear Cache + Debug Mode does not resolve the error
Domain resolves externally but not within Liongard
Logs show persistent execSync failures
You suspect an Inspector-side defect
Include:
Domain name
dig/nslookup results
WHOIS results
Clear Cache + Debug Mode logs
Any other relevant details or screenshots.
Our Support team is happy to help 😇
💬 Start a chat with Leo (Our AI Assistant) or connect with a live support engineer.
📧 Email: support@liongard.com
Note ‼️
We sometimes link to third-party tools as optional reference material. These resources are provided for convenience only—Liongard does not control or guarantee their functionality, accuracy, or availability. Please use them at your own discretion.