🟡 Medium   ⏱ 5–30 min  Last verified: 19 May 2026
Affected versions: Oracle Linux 10

📖 ~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

Resolvers stay unchanged, causing failed package downloads and service discovery timeouts.

Environment & Reproduction

Most common on DHCP interfaces where profile and runtime state diverge.

nmcli dev show | grep -E 'IP4.DNS|GENERAL.CONNECTION'

Root Cause Analysis

Connection profile settings are overridden by DHCP or stale resolv.conf ownership behavior.

Quick Triage

Check active profile, dispatcher scripts, and DNS priority settings.

sudo journalctl -u NetworkManager --since -1h

Step-by-Step Diagnosis

Inspect ipv4.ignore-auto-dns and verify if systemd-resolved integration is active.

nmcli con show
Illustrative mockup for oracle-linux-10 — nmcli_dns_show
Inspecting DNS via nmcli — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Set static DNS in profile, disable auto DNS for that connection, then reconnect.

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sudo nmcli con mod  ipv4.ignore-auto-dns yes ipv4.dns '1.1.1.1 9.9.9.9' && sudo nmcli con up
Illustrative mockup for oracle-linux-10 — nmcli_modify_dns
Applying DNS profile changes — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Set DNS via DHCP server reservations or use split DNS with local caching resolver.

Verification & Acceptance Criteria

dig and host queries resolve through expected nameservers after reconnect/reboot.

Rollback Plan

Re-enable auto DNS and restore previous connection profile values.

Prevention & Hardening

Manage NetworkManager profiles declaratively and monitor DNS drift with periodic checks.

Related: resolv.conf immutable bit, DNSSEC validation failures, and search domain misconfiguration.

Related tutorial: View the step-by-step tutorial for oracle-linux-10.

View all oracle-linux-10 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

RHEL networking and NetworkManager DNS behavior documentation.

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