shell:$ nslookup -timeout=2 -retry=1 'fast.a.klaviyo.com'
Server:		1.1.1.1
Address:	1.1.1.1#53

Non-authoritative answer:
fast.a.klaviyo.com	canonical name = klaviyo-onsite.map.fastly.net.
Name:	klaviyo-onsite.map.fastly.net
Address: 151.101.2.133
Name:	klaviyo-onsite.map.fastly.net
Address: 151.101.66.133
Name:	klaviyo-onsite.map.fastly.net
Address: 151.101.130.133
Name:	klaviyo-onsite.map.fastly.net
Address: 151.101.194.133