Robtex

Up: 13.33.54.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 13.33.55.0/25
Down right: 13.33.55.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
13.33.55.29	PTR	server-13-33-55-29.man50.r.cloudfront.net
13.33.55.29	A	secretsales.com
13.33.55.31	PTR	server-13-33-55-31.phx50.r.cloudfront.net
13.33.55.31	A	gefran.slack.com
13.33.55.31	A	virtualbaseball.slack.com