shell:$ nslookup -timeout=2 -retry=1 'free.tunneling.dpdns.org'
Server:		75.98.161.224
Address:	75.98.161.224#53

Non-authoritative answer:
Name:	free.tunneling.dpdns.org
Address: 172.67.205.72
Name:	free.tunneling.dpdns.org
Address: 104.21.37.70
Name:	free.tunneling.dpdns.org
Address: 2606:4700:3031::6815:2546
Name:	free.tunneling.dpdns.org
Address: 2606:4700:3037::ac43:cd48