Network manager and split DNS for a VPN?

[Tom H]

On Wed, Apr 12, 2017 at 5:45 AM, Chris Green <cl at isbd.net> wrote:
> On Wed, Apr 12, 2017 at 09:13:49AM +0200, Xen wrote:
>>
>> For a user seeing /etc/resolv.conf output something like:
>>
>> 127.0.1.1 localhost
>>
>> and then not being able to verify the contents of that nameserver is a bit
>> disheartening.
>>
>> Particularly as I think the commands are updated over dbus and the user has
>> no control over that at all.
>>
> I absolutely agree, it's a pain not being able to easily see where
> one's DNS is *actually* being resolved.
>
> The way that dnsmasq is used 'automatically' by Network Manager is
> very inflexible.
>
> There should be:-
>
> A well documented way to configure the dnsmasq used by Network
> Manager as a full/proper dnsmasq, or a way to unhook it from
> Network Manager.

When you're using dhcp, by default:

- set "dns=none" in "/etc/NetworkManager/NetworkManager.conf" and NM
won't populate "/etc/resolv.conf"

- set "dns=default" in "/etc/NetworkManager/NetworkManager.conf" and
NM'll populate "/run/NetworkManager/resolv.conf" with the dhcp
client's nameserver(s)

- set "dns=dnsmasq" in "/etc/NetworkManager/NetworkManager.conf" and
NM'll populate "/run/NetworkManager/resolv.conf" with "127.0.1.1" and
dnsmasq'll use the dhcp client's nameserver(s)


> Somewhere easy to find the actual upstream DNS servers (i.e. the
> ones recommended by your ISP or whatever) that are being used
.
See my previous email about issuing nmcli.