shell:$ nslookup -timeout=2 -retry=1 'captive.apple.com'
Server:		75.98.161.224
Address:	75.98.161.224#53

Non-authoritative answer:
captive.apple.com	canonical name = captive-cidr.origin-apple.com.akadns.net.
captive-cidr.origin-apple.com.akadns.net	canonical name = captive-geo.origin-apple.com.akadns.net.
captive-geo.origin-apple.com.akadns.net	canonical name = captive.g.aaplimg.com.
Name:	captive.g.aaplimg.com
Address: 17.253.11.197
Name:	captive.g.aaplimg.com
Address: 17.253.11.196
Name:	captive.g.aaplimg.com
Address: 2620:149:a08:f100::196
Name:	captive.g.aaplimg.com
Address: 2620:149:a08:f000::195