Robtex

Up: 13.35.60.0/22
Can't show all results, try to descend to a more specific CIDR
Down left: 13.35.62.0/24
Down right: 13.35.63.0/24
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
13.35.62.171	A+PTR	server-13-35-62-171.jnb50.r.cloudfront.net
13.35.62.173	A+PTR	server-13-35-62-173.jnb50.r.cloudfront.net
13.35.62.173	A	alc4-phase-2.slack.com
13.35.62.173	A	freelancerscloud.slack.com