Ubuntu 16.04 (Security onion) not using dns configured in /etc/network/interfaces

Hi everyone, thanks for entertaining what should be a simple question. Thanks for reading.

I am trying to set up a security onion deployment, which runs on Ubuntu 16.04. There is a setup script which configures /etc/network/interfaces, and it successfully configures my nic, but on one of three servers set up this way, DNS is not working.

If I try to look up linuxquestions.org, I get the message: ;; connection timed out; no servers could be reached, and I can verify through tcpdump that no packets are sent to my dns server. If I try to ping linuxquestions.org, I just get an "unknown host" error.

If, however, I run something like
root@Seconion:~# nslookup linuxquestions.org 10.101.0.194 I get the following:
Server:10.101.0.194
Address:10.101.0.194#53

Non-authoritative answer:
Name:linuxquestions.org
Address: 35.244.195.25

/etc/network/interfaces looks like the following:
auto eno1
iface eno1 inet static
address 10.51.0.160
gateway 10.51.0.1
netmask 255.255.255.0
dns-nameservers 10.101.0.194 1.1.1.1
dns-domain mydomain.local

Any help, of course, will be greatly appreciated.

Thanks,
Kevin