ModdIt
Maybe the instructions under below link can help out, I used the description and commands to set free dns servers.
It survived a reboot and seems to work as expected. It will I think work for you. Setting in connmann was pretty much hit
and miss and did not survive rebooting due resolvconf workings.
http://www.ricmedia.com/set-permanent-dns-nameservers-ubuntu-debian-resolv-conf/
An easy permanent DNS setup is one of very few things I really would like to see in antix, dhcp seems to push me to google
and cloudflare which are not exactly the epicenter of freedom and privacy.