RHEL 9 must configure a DNS processing mode in Network Manager.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-257949 | RHEL-09-252040 | SV-257949r1014841_rule | CCI-000366 | medium |
| Description | ||||
| In order to ensure that DNS resolver settings are respected, a DNS mode in Network Manager must be configured. | ||||
| STIG | Date | |||
| Red Hat Enterprise Linux 9 Security Technical Implementation Guide | 2025-05-14 | |||
Details
Check Text (C-257949r1014841_chk)
Verify that RHEL 9 has a DNS mode configured in Network Manager.
$ NetworkManager --print-config
[main]
dns=none
If the dns key under main does not exist or is not set to "none" or "default", this is a finding.
Note: If RHEL 9 is configured to use a DNS resolver other than Network Manager, the configuration must be documented and approved by the information system security officer (ISSO).
Fix Text (F-61614r925833_fix)
Configure NetworkManager in RHEL 9 to use a DNS mode.
In "/etc/NetworkManager/NetworkManager.conf" add the following line in the "[main]" section:
dns = none
NetworkManager must be reloaded for the change to take effect.
$ sudo systemctl reload NetworkManager