🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026
Affected versions: RHEL 10.0 RHEL 10.1

📖 ~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 intermittently fail to resolve internal domains, breaking package and service dependencies.

Environment & Reproduction

Appears when /etc/resolv.conf points to unexpected stub resolver while NM pushes different DNS servers.

getent hosts repo.internal
cat /etc/resolv.conf

Root Cause Analysis

DNS management ownership is split between systemd-resolved and NetworkManager.

Quick Triage

Inspect resolver service state and NM DNS settings.

systemctl status systemd-resolved
nmcli dev show | grep DNS

Step-by-Step Diagnosis

Trace query path and compare configured upstream DNS endpoints.

resolvectl status
journalctl -u systemd-resolved -n 100
Illustrative mockup for rhel-10 — dns_mismatch_diag
Resolver mismatch and lookup failures — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Choose one resolver authority and align config files accordingly.

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sudo systemctl disable --now systemd-resolved
sudo nmcli connection modify prod-lan ipv4.dns '10.0.0.10 10.0.0.11' ipv4.ignore-auto-dns yes
sudo systemctl restart NetworkManager
Illustrative mockup for rhel-10 — dns_mismatch_fix
Resolver stack aligned and verified — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Enable systemd-resolved intentionally and configure NM to use dns=systemd-resolved.

Verification & Acceptance Criteria

DNS lookups are consistent and low-latency for required zones.

getent hosts repo.internal
dig +short repo.internal

Rollback Plan

Re-enable previous resolver service mode if new configuration causes regressions.

sudo systemctl enable --now systemd-resolved

Prevention & Hardening

Standardize resolver architecture per environment and validate after network changes.

Related to split-horizon DNS, stale nscd caches, and DHCP-supplied DNS drift.

Related tutorial: View the step-by-step tutorial for rhel-10.

View all rhel-10 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

RHEL name resolution stack guidance with NetworkManager integration.

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