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Chapter 32. Manually configuring the /etc/resolv.conf file

By default, NetworkManager on Red Hat Enterprise Linux (RHEL) 8 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.

Note

Alternatively, if you require a specific order of DNS servers in /etc/resolv.conf, see Configuring the order of DNS servers.

32.1. 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

  1. As the root user, create the /etc/NetworkManager/conf.d/90-dns-none.conf file with the following content by using a text editor:

    [main]
    dns=none
  2. Reload the NetworkManager service:

    # systemctl reload NetworkManager
    Note

    After you reload the service, NetworkManager no longer updates the /etc/resolv.conf file. However, the last contents of the file are preserved.

  3. Optionally, remove the Generated by NetworkManager comment from /etc/resolv.conf to avoid confusion.

Verification steps

  1. Edit the /etc/resolv.conf file and manually update the configuration.
  2. Reload the NetworkManager service:

    # systemctl reload NetworkManager
  3. Display the /etc/resolv.conf file:

    # cat /etc/resolv.conf

    If you successfully disabled DNS processing, NetworkManager did not override the manually configured settings.

Additional resources