shell:$ nslookup -timeout=2 -retry=1 'ec2-23-21-29-22.compute-1.amazonaws.com'
Server:		75.98.161.224
Address:	75.98.161.224#53

Non-authoritative answer:
Name:	ec2-23-21-29-22.compute-1.amazonaws.com
Address: 23.21.29.22