I think you should have a look at what your system does to /etc/resolve.conf, or more specifically, how it builds it. Look here: /lib/dhcpcd/dhcpcd-hooks/20-resolv.conf Also look at the man page for 'resolvconf" to get an idea of what is going on. Also look at the dhcpcd man page. I just cannot remember off hand if dhcpcd will take domain info from the dhcp server that provides the lease.