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For some strange reason Ubuntu / Systemd do not want to update resolv.conf for one of my interfaces. But works fine for the others. So the systemd-resolved only works for the two first interfaces. The last responds SERVFAIL to all requests, since resolv.conf is generated empty.

I am not using dnsmasq or resolvconf.

Enable wired only:

nameserver 192.168.1.21 search barnabas.dk

Enable wireless only nameserver 192.168.1.21 search barnabas.dk

Enable Mobile broadband only:

Should be 95.209.200.69 95.209.200.70

The interface to the mobile broadband is configured just fine and if I manually update the resolv.conf with the needed nameserver entry all is well.

No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 17.04 Release: 17.04 Codename: zesty

Why do systemd-resolved refuse to update for the last interface?

Thanks.

Nikolaj Hansen
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3 Answers3

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Final solution was to disable systemd-resolved, enable dnsmasq and set the network-manager to use resolvconf to update the /etc/resolv.conf. That seems to work in all instances of network configuration for me.

Nikolaj Hansen
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I figured this out, it's a bug in (at least) network-manager 1.4.4-1ubuntu3.2

I'm not sure when it was introduced or resolved, but with network-manager 1.8.2-1ubuntu1 dns resolution works properly on wwan/3g as well.

For ubuntu 17.04 i used the 1.8.2 version from artful-proposed: https://launchpad.net/ubuntu/+source/network-manager/1.8.2-1ubuntu1/+build/13090166

You will need to update both libnm0 and network-manager: https://launchpad.net/ubuntu/+source/network-manager/1.8.2-1ubuntu1/+build/13090166/+files/libnm0_1.8.2-1ubuntu1_amd64.deb https://launchpad.net/ubuntu/+source/network-manager/1.8.2-1ubuntu1/+build/13090166/+files/network-manager_1.8.2-1ubuntu1_amd64.deb

Download them, then install by:

sudo dpkg -i libnm0_1.8.2-1ubuntu1_amd64.deb network-manager_1.8.2-1ubuntu1_amd64.deb

I restarted network-manager and modem-manager although I guess modem-manager was unnecessary.

sudo service network-manager restart
sudo service modem-manager restart
Oskar Stenman
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I had the same problem, and got it working by setting FallbackDNS in /etc/systemd/resolved.conf instead. It only adds that server if no other nameservers are configured.

Simon B. Jensen
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