Ubuntu 14.04 LTS DNS resolution fails while IP ping works

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

External services cannot be reached by hostname, causing outages.

Environment & Reproduction

Often appears after network manager changes or DHCP misconfiguration.

Root Cause Analysis

Invalid nameserver entries or resolver file overwritten unexpectedly.

Quick Triage

Test raw IP connectivity, then test hostname lookup with dig or nslookup.

Step-by-Step Diagnosis

Audit resolver chain from /etc/resolv.conf to upstream DNS responsiveness.

Solution – Primary Fix

Set reliable nameservers and persist config through interface settings.

Solution – Alternative Approaches

Use local caching DNS or alternate upstream providers.

Verification & Acceptance Criteria

Forward and reverse lookups succeed for required domains.

Rollback Plan

Restore previous resolver file and DHCP options if regressions appear.

Prevention & Hardening

Monitor DNS latency and enforce validated resolver templates.

Related Errors & Cross-Refs

Temporary failure in name resolution and SERVFAIL responses.

Related tutorial: View the step-by-step tutorial for Ubuntu 14.04 LTS.

View all Ubuntu 14.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu DNS troubleshooting and resolver documentation.