🟡 Medium   ⏱ 5–30 min  Last verified: 19 May 2026

📖 ~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

Yum and remote service endpoints fail with host resolution errors, interrupting updates and deployment tasks.

Environment & Reproduction

Appears after DHCP changes, static profile edits, cloud-init overrides, or inconsistent `/etc/resolv.conf` ownership.

Root Cause Analysis

NetworkManager profile lacks valid DNS entries or service restart rewrites resolver settings with stale values.

Quick Triage

Run `nmcli dev show`, `cat /etc/resolv.conf`, and check `systemctl status network NetworkManager` for active manager.

Step-by-Step Diagnosis

Compare connection profile DNS settings, validate resolver reachability, and inspect `journalctl -u NetworkManager`.

Illustrative mockup for rhel-7 — rhel7-networkmanager-dns-state.webp
DNS resolver and NetworkManager connection profile review — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Apply correct DNS via `nmcli`, reload connection, and confirm yum reaches repository FQDNs reliably.

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Illustrative mockup for rhel-7 — rhel7-fix-resolv-networkmanager.webp
Applying persistent DNS settings and restarting network service — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Pin static resolver config, disable conflicting scripts, or use local caching resolver for resilient lookups.

Verification & Acceptance Criteria

`dig` and `yum repolist` succeed repeatedly across reboots and network service restarts.

Rollback Plan

Restore previous NetworkManager profile from backup and restart affected service if new DNS path regresses.

Prevention & Hardening

Standardize DNS in host templates and monitor resolver latency with alerting tied to yum failures.

`systemctl restart NetworkManager && journalctl -u NetworkManager -n 80 && yum check-update`

Related tutorial: View the step-by-step tutorial for rhel-7.

View all rhel-7 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

RHEL 7 Networking Guide and NetworkManager operational references for DNS lifecycle management.

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