Ubuntu 14.04 LTS – DNS resolution fails after network changes

📖 ~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

Hosts cannot resolve domain names, causing package, API, and application failures.

Environment & Reproduction

Occurs after edits to network interfaces, DHCP settings, or resolv.conf integration.

Root Cause Analysis

Incorrect nameserver entries or resolver overwrite behavior breaks DNS lookups.

Quick Triage

Test raw connectivity, then compare DNS responses across resolvers and tools.

Step-by-Step Diagnosis

Review resolver configuration chain and active interface settings.

Solution – Primary Fix

Set valid resolvers and persistent network configuration for stable name resolution.

Solution – Alternative Approaches

Use temporary resolver overrides while implementing permanent interface updates.

Verification & Acceptance Criteria

Forward and reverse DNS queries succeed for required internal and external hosts.

Rollback Plan

Restore prior network and resolver files from known-good backups.

Prevention & Hardening

Standardize network templates and monitor resolver drift after reboots.

Related Errors & Cross-Refs

Related issues include temporary failure resolving, NXDOMAIN, and timeout errors.

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

Review Ubuntu networking and resolver management documentation.