shell:$ nslookup -timeout=2 -retry=1 'speedtest.xfinity.com'
Server:		1.1.1.1
Address:	1.1.1.1#53

Non-authoritative answer:
speedtest.xfinity.com	canonical name = cdn.speedtest-prod.xcr.comcast.net.
Name:	cdn.speedtest-prod.xcr.comcast.net
Address: 96.96.217.35
Name:	cdn.speedtest-prod.xcr.comcast.net
Address: 96.96.217.57
Name:	cdn.speedtest-prod.xcr.comcast.net
Address: 96.96.217.1
Name:	cdn.speedtest-prod.xcr.comcast.net
Address: 96.96.217.28
Name:	cdn.speedtest-prod.xcr.comcast.net
Address: 2001:558:fe10:14::1
Name:	cdn.speedtest-prod.xcr.comcast.net
Address: 2001:558:fe10:14::1c
Name:	cdn.speedtest-prod.xcr.comcast.net
Address: 2001:558:fe10:14::23
Name:	cdn.speedtest-prod.xcr.comcast.net
Address: 2001:558:fe10:14::39