On Tue, Feb 18, 2020 at 04:37:29PM +0100, Nicolas Kovacs wrote:
Le 18/02/2020 à 12:28, Anand Buddhdev a écrit :
Neither. The DNS configuration should not normally be bound to a specific interface, so don't configure it with any interface. If you do, and that interface goes down, your DNS config also disappears.
I would like to do that very much, only NetworkManager makes you jump through burning loops to do so.
With network-scripts, it was just a matter of editing resolv.conf with nameserver and search domain directives.
I can't do that anymore, because /etc/resolv.conf gets squashed by NetworkManager. If I don't fill in DNS information for the interfaces, then all I get is an empty "#Generated by NetworkManager" line.
On the other hand, using nmtui, the only place where I can actually fill in DNS information is in the interface-specific dialogs.
After googling around for this problem, it looks like I'm not the only one scratching my head.
According to 'man nm-settings-ifcfg-rh', PEERDNS=no is the old network-services services mechanism for not changing /etc/resolv.conf, while in NM it just means never add automatic nameservers to resolv.conf from DHCP, PPP, VPN, etc. Turning off all DNS updates means adding:
[main] dns=none
... to the NetworkManager.conf (or preferably in an /etc/NetworkManager/conf.d/ file) is probably going to be the most effective way. I've seen PEERDNS=no make NetworkManager not overwrite my resolv.conf but maybe I should be extra careful and drop in a config file that turns off all dns updating features of NetworkManager.