shell:$ nslookup -timeout=2 -retry=1 'r.rockcdn.us'
Server:		75.98.161.224
Address:	75.98.161.224#53

Non-authoritative answer:
Name:	r.rockcdn.us
Address: 172.67.128.61
Name:	r.rockcdn.us
Address: 104.21.0.197
Name:	r.rockcdn.us
Address: 2606:4700:3030::6815:c5
Name:	r.rockcdn.us
Address: 2606:4700:3033::ac43:803d