How to change DNS on a minimal networking setup

Question

How can I replace my DNS? I am not using a network manager, except for systemd-networkd and wpa_supplicant for wireless, with wpa_cli. I'm on Arch Linux, if it matters.

Although I can add DNS to my config, systemctl restart systemd-resolved overwrites /etc/resolv.conf (sym linked to /run/systemd/resolve/resolv.conf), or a reboot, somehow add the default ISP DNS's to /etc/resolv.conf. Does anyone know why, or how to resolve this issue to only use the DNS that I configured?

When I edit /etc/resolv.conf to only contain

nameserver 208.67.222.222
nameserver 208.67.220.220 

and run systemctl restart systemd-resolved or do a reboot, the default ISP DNS's are overwritten, and cat /etc/resolv.conf is this:

# 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 75.75.75.75
nameserver 192.168.1.1
nameserver 208.67.222.222
# Too many DNS servers configured, the following entries may be ignored.
nameserver 75.75.76.76
nameserver 208.67.220.220

As described under man resolved.conf, I ensured that I only have one config file, /etc/systemd/resolved.conf.d/resolv.conf, containing

#  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.
#
# See resolved.conf(5) for details

[Resolve]
DNS=208.67.222.222 208.67.220.220
#FallbackDNS=8.8.8.8 8.8.4.4 2001:4860:4860::8888 2001:4860:4860::8844
#LLMNR=yes

and no other files defining my DNS from all the configuration files under here:

/etc/systemd/resolved.conf

/etc/systemd/resolved.conf.d/*.conf

/run/systemd/resolved.conf.d/*.conf

/usr/lib/systemd/resolved.conf.d/*.conf

I don't believe I am running any dhcpcd or netctl service either, and systemctl | grep dhcpcd, and systemctl | grep netctl returns nothing.

Answer 1

I resolved this issue by adding the following to my network profiles under /etc/systemd/network/*.network:

[DHCP]
UseDNS=false

By default, this is true, meaning DNS servers are pulled from the DHCP network connection. If I disable this feature, and input my own static DNS (ie OpenDNS), then I can ensure that I will only be using the DNS of my choosing.