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

Non-authoritative answer:
Name:	challenges.cloudflare.com
Address: 104.18.94.41
Name:	challenges.cloudflare.com
Address: 104.18.95.41
Name:	challenges.cloudflare.com
Address: 2606:4700::6812:5e29
Name:	challenges.cloudflare.com
Address: 2606:4700::6812:5f29