systemd-networkd no DNS resolution after upgrade

[tchelovek]

I have presently 4 units running ArchLinux Arm an Odroid C1 (linux-odroid-c1 3.10.80-18 armv7h), a Raspberry Pi 2B+ ( linux-raspberrypi 4.1.15-1 armv7h) and two Raspberry Pi B+ ( linux-raspberrypi 4.1.15-1 armv6h )

systemd is 228-3 for all of them

All have their network set up with systemd-networkd using static IP following the document at https://wiki.archlinux.org/index.php/Systemd-networkd.

After upgrading all of them with pacman -Syu only the Odroid C1 has internet access, while all of the Raspberries fail.

The only way to overcome the situation is adding the DNS servers to /etc/hosts, alternatively I can add DNS entries to /etc/systemd/network/eth0.network, which works, but will result in the link having two Ip-adresses.

Not sure what causes the problem and what the proper remedy would be.

I am posting here as the suggested Git-Hub doesn't seem to have a place for bug reports.

$this->bbcode_second_pass_code('', '/etc/resolv.conf

# This file is managed by systemd-resolved(8). Do not edit.
#
# Third party programs must not access this file directly, but
# only through the symlink at /etc/resolv.conf. To manage
# resolv.conf(5) in a different way, replace the symlink by a
# static file or a different symlink.

nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 2001:4860:4860::8888
# Too many DNS servers configured, the following entries may be ignored.
nameserver 2001:4860:4860::8844')

$this->bbcode_second_pass_code('', '/etc/systemd/network/eth0.network

[Match]
Name=eth0

[Network]
Address=192.168.178.21/24
Gateway=192.168.178.1')

[technosf]

Fixed IP's or set by DHCP?
If DHCP:
o Is the DHCP server broadcasting the DNS servers?
o Are you running a local DNS cache, say, dnsmasq?
o Is your firewall blocking DNS on any local cache server?
o Why are you setting the gateway?

If fixed, then, yup, you have to set the DNS servers, and the interface IP

$this->bbcode_second_pass_quote('', 'F')ixed IP's or set by DHCP?

[tchelovek]

After milking GOOGLE for some time, I found some hint at https://github.com/systemd/systemd/issues/1982

I now changed /etc/systemd/network/wlan0.network to:

$this->bbcode_second_pass_code('', '[Match]
Name=wlan0

[Network]
DNS=no
DNS=192.168.178.1
IPv6AcceptRouterAdvertisements=false
Address=192.168.178.42/24
Gateway=192.168.178.1')

and /etc/systemd/resolved.conf to

$this->bbcode_second_pass_code('', '# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# Defaults can be restored by simply deleting this file.
#
# See resolved.conf(5) for details

[Resolve]
DNS=192.168.178.1
#FallbackDNS=8.8.8.8 8.8.4.4 2001:4860:4860::8888 2001:4860:4860::8844
LLMNR=yes
')

/etc/resolv.conf now simply reads

$this->bbcode_second_pass_code('', '# This file is managed by systemd-resolved(8). Do not edit.
#
# Third party programs must not access this file directly, but
# only through the symlink at /etc/resolv.conf. To manage
# resolv.conf(5) in a different way, replace the symlink by a
# static file or a different symlink.

nameserver 192.168.178.1

')

And, according to https://www.mail-archive.com/systemd-devel@lists.freedesktop.org/msg34727.html it looks like a bug by downstream not backporting the upstream solution.