Ubuntu 22.04 DNS resolution failed

📖 ~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

Ubuntu 22.04 network connectivity may exist while DNS name resolution fails.

Environment & Reproduction

Ping by IP works, but domain lookups fail in browser, apt, and command-line tools.

Root Cause Analysis

Broken resolver config, unreachable DNS server, or stale systemd-resolved cache.

Quick Triage

Test IP reachability first, then compare behavior using resolvectl query and dig.

Step-by-Step Diagnosis

Run resolvectl status, resolvectl query ubuntu.com, and systemctl status systemd-resolved.

Solution – Primary Fix

Set valid DNS servers in netplan or NetworkManager, restart resolved, and flush DNS cache.

Solution – Alternative Approaches

Confirm domain resolution across terminal tools and web applications.

Verification & Acceptance Criteria

Use reliable DNS endpoints and avoid manual edits to generated resolver files.

Rollback Plan

Prefer trusted DNS providers and validate secure HTTPS certificate chains after fixes.

Prevention & Hardening

Low-latency resolvers improve package downloads and browser responsiveness.

Related Errors & Cross-Refs

Revert recent netplan or NetworkManager DNS changes and reapply known-good settings.

Related tutorial: View the step-by-step tutorial for Ubuntu 22.04 LTS.

View all Ubuntu 22.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Use resolvectl, netplan docs, and Ubuntu 22.04 DNS troubleshooting guidance.