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

Non-authoritative answer:
go.duo.com	canonical name = duosecurity-ssl.mktoweb.com.
duosecurity-ssl.mktoweb.com	canonical name = sj02.mktossl.com.
Name:	sj02.mktossl.com
Address: 104.17.73.206
Name:	sj02.mktossl.com
Address: 104.17.70.206
Name:	sj02.mktossl.com
Address: 104.17.71.206
Name:	sj02.mktossl.com
Address: 104.17.72.206
Name:	sj02.mktossl.com
Address: 104.17.74.206