RHEL 10 – nmcli DNS settings not applied due to resolver override conflicts – Fix & Prevention

📖 ~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 resolve against wrong DNS servers, causing internal name lookup failures.

Environment & Reproduction

Occurs when static resolv.conf edits conflict with NetworkManager controls.

nmcli connection show
cat /etc/resolv.conf
resolvectl status

Root Cause Analysis

Connection profile DNS fields are unset or overridden by external resolver management.

Quick Triage

Check active connection DNS and resolver ownership.

nmcli -f NAME,DEVICE,IP4.DNS connection show --active
ls -l /etc/resolv.conf
journalctl -u NetworkManager -n 80

Step-by-Step Diagnosis

Inspect profile flags for auto DNS and resolver plugin behavior.

nmcli connection show eth0 | grep -E 'ipv4.dns|ipv4.ignore-auto-dns'
grep -R '^dns=' /etc/NetworkManager/NetworkManager.conf
resolvectl dns

Solution – Primary Fix

Set explicit DNS in profile and reload connection.

nmcli connection modify eth0 ipv4.dns '10.10.10.10 10.10.10.11' ipv4.ignore-auto-dns yes
nmcli connection down eth0 && nmcli connection up eth0
systemctl restart NetworkManager

Solution – Alternative Approaches

Use DHCP-provided DNS and remove static resolver overrides.

nmcli connection modify eth0 ipv4.ignore-auto-dns no
rm -f /etc/resolv.conf
ln -s /run/NetworkManager/resolv.conf /etc/resolv.conf

Verification & Acceptance Criteria

Resolver shows expected servers and internal/external lookups succeed.

cat /etc/resolv.conf
getent hosts internal.example.com
getent hosts redhat.com

Rollback Plan

Restore previous NetworkManager profile values if application behavior changes.

nmcli connection reload
nmcli connection modify eth0 ipv4.ignore-auto-dns no

Prevention & Hardening

Manage DNS exclusively via NetworkManager profiles in automation.

nmcli connection export eth0 /root/eth0.nmconnection

Related Errors & Cross-Refs

Linked to firewalld DNS egress restrictions and split-DNS VPN setups.

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 NetworkManager DNS handling and resolver integration docs.