The TransPort router is a caching DNS relay, not actually a DNS server. The last 50 DNS look-ups will be cached.
Yes it will respond to DNS requests, but this is because the router then forwards the DNS query to the real DNS server and relays the reply back to the originating host.
The Sarian DNS server cache can be viewed (dns 0 status svr) or cleared (dns 0 clear svr).
Hope this helps.
Digi (UK) Support