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dnscentosnetworkmanager

Stop network manager from updating resolv.conf

I changed nameserver in /etc/resolv.conf but when I connected vpn in my CentOS, network-manager pushed my previous DNS back into /etc/resolv.conf.

I do not want network-manager to add DNS servers received from DHCP to my /etc/resolv.conf.

Any solution?

Solution

  • The "brute force" way to prevent a file being updated in Linux could be to use chattr, for example you could do:

    chattr +i /etc/resolv.conf

    To remove the i - Immutable attribute so that you could modify the file again run:

    chattr -i /etc/resolv.conf

    Another way could be to configure /etc/NetworkManager/NetworkManager.conf to not modify the DNS:

    [main]
dns=none

    From the man:

    dns
       Set the DNS (resolv.conf) processing mode.

       default: The default if the key is not specified. NetworkManager will update
       resolv.conf to reflect the nameservers provided by currently active connections.

       dnsmasq: NetworkManager will run dnsmasq as a local caching nameserver, using a "split
       DNS" configuration if you are connected to a VPN, and then update resolv.conf to point
       to the local nameserver.

       none: NetworkManager will not modify resolv.conf.