Chapter 20. Manually configuring the /etc/resolv.conf file
By default, NetworkManager dynamically updates the /etc/resolv.conf file with the DNS settings from active NetworkManager connection profiles. However, you can disable this behavior and manually configure DNS settings in /etc/resolv.conf.
Alternatively, if you require a specific order of DNS servers in /etc/resolv.conf, see Configuring the order of DNS servers.
20.1. Disabling DNS processing in the NetworkManager configuration
By default, NetworkManager manages DNS settings in the /etc/resolv.conf file, and you can configure the order of DNS servers. Alternatively, you can disable DNS processing in NetworkManager if you prefer to manually configure DNS settings in /etc/resolv.conf.
Procedure
As the root user, create the
/etc/NetworkManager/conf.d/90-dns-none.conffile with the following content by using a text editor:[main] dns=none
Reload the
NetworkManagerservice:# systemctl reload NetworkManagerNoteAfter you reload the service, NetworkManager no longer updates the
/etc/resolv.conffile. However, the last contents of the file are preserved.-
Optionally, remove the
Generated by NetworkManagercomment from/etc/resolv.confto avoid confusion.
Verification
-
Edit the
/etc/resolv.conffile and manually update the configuration. Reload the
NetworkManagerservice:# systemctl reload NetworkManagerDisplay the
/etc/resolv.conffile:# cat /etc/resolv.confIf you successfully disabled DNS processing, NetworkManager did not override the manually configured settings.
Troubleshooting
Display the NetworkManager configuration to ensure that no other configuration file with a higher priority overrode the setting:
# NetworkManager --print-config ... dns=none ...
Additional resources
-
NetworkManager.conf(5)man page - Configuring the order of DNS servers using NetworkManager
20.2. Replacing /etc/resolv.conf with a symbolic link to manually configure DNS settings
By default, NetworkManager manages DNS settings in the /etc/resolv.conf file, and you can configure the order of DNS servers. Alternatively, you can disable DNS processing in NetworkManager if you prefer to manually configure DNS settings in /etc/resolv.conf. For example, NetworkManager does not automatically update the DNS configuration if /etc/resolv.conf is a symbolic link.
Prerequisites
-
The NetworkManager
rc-managerconfiguration option is not set tofile. To verify, use theNetworkManager --print-configcommand.
Procedure
-
Create a file, such as
/etc/resolv.conf.manually-configured, and add the DNS configuration for your environment to it. Use the same parameters and syntax as in the original/etc/resolv.conf. Remove the
/etc/resolv.conffile:# rm /etc/resolv.confCreate a symbolic link named
/etc/resolv.confthat refers to/etc/resolv.conf.manually-configured:# ln -s /etc/resolv.conf.manually-configured /etc/resolv.conf
Additional resources
-
resolv.conf(5)man page -
NetworkManager.conf(5)man page - Configuring the order of DNS servers using NetworkManager
