πŸ“– ~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

Name lookups intermittently fail, causing package downloads and API calls to fail unpredictably.

Environment & Reproduction

Use nmcli connection show and repeatedly query dig against internal and external hostnames.

Root Cause Analysis

DHCP overwrites static DNS, stale resolver cache, or split DNS options are misconfigured.

Quick Triage

Check resolvectl status, nmcli device show, and journalctl -u NetworkManager for lease events.

Step-by-Step Diagnosis

Review active profile DNS entries, verify search domains, and trace packet flow to DNS servers.

Illustrative mockup for rhel-8 β€” nm-dns-107-1
NetworkManager profile with incorrect DNS settings β€” Illustrative mockup β€” Progressive Robot

Solution – Primary Fix

Update profile via nmcli connection modify ipv4.dns and disable auto DNS if required, then reconnect.

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Illustrative mockup for rhel-8 β€” nm-dns-107-2
Resolved DNS behavior after nmcli profile update β€” Illustrative mockup β€” Progressive Robot

Solution – Alternative Approaches

Deploy local caching resolver and enforce nameserver policy through central DHCP controls.

Verification & Acceptance Criteria

dig and getent hosts return consistent answers and NetworkManager logs show no resolver churn.

Rollback Plan

Reapply previous nmcli profile settings and restart NetworkManager if connectivity regresses.

Prevention & Hardening

Template stable connection profiles and monitor DNS latency and SERVFAIL rates.

Related: Temporary failure in name resolution, Could not resolve host, and DNS timeout.

Related tutorial: View the step-by-step tutorial for rhel-8.

View all rhel-8 tutorials on the Tutorials Hub β†’

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Consult RHEL 8 NetworkManager and DNS resolver behavior documentation.

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