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

Non-authoritative answer:
app.youtube.com	canonical name = youtube-ui.l.google.com.
Name:	youtube-ui.l.google.com
Address: 142.250.191.110
Name:	youtube-ui.l.google.com
Address: 142.250.190.142
Name:	youtube-ui.l.google.com
Address: 142.250.191.142
Name:	youtube-ui.l.google.com
Address: 142.250.189.110
Name:	youtube-ui.l.google.com
Address: 172.217.4.46
Name:	youtube-ui.l.google.com
Address: 142.250.190.46
Name:	youtube-ui.l.google.com
Address: 172.217.5.14
Name:	youtube-ui.l.google.com
Address: 142.250.190.14
Name:	youtube-ui.l.google.com
Address: 142.251.41.142
Name:	youtube-ui.l.google.com
Address: 142.250.190.78
Name:	youtube-ui.l.google.com
Address: 142.250.190.110
Name:	youtube-ui.l.google.com
Address: 172.217.1.110
Name:	youtube-ui.l.google.com
Address: 142.251.34.238
Name:	youtube-ui.l.google.com
Address: 142.250.191.206
Name:	youtube-ui.l.google.com
Address: 142.250.191.174
Name:	youtube-ui.l.google.com
Address: 142.250.191.238
Name:	youtube-ui.l.google.com
Address: 2607:f8b0:4009:817::200e
Name:	youtube-ui.l.google.com
Address: 2607:f8b0:4009:81a::200e
Name:	youtube-ui.l.google.com
Address: 2607:f8b0:4009:819::200e
Name:	youtube-ui.l.google.com
Address: 2607:f8b0:4009:818::200e