Robtex

Up: 157.240.28.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 157.240.28.0/25
Down right: 157.240.28.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
157.240.28.1	A+PTR	livestream-edgetee-upload-shv-01-den4.facebook.com
157.240.28.10	A+PTR	edge-video-shv-01-den4.fbcdn.net
157.240.28.10	A	video-den4-1.xx.fbcdn.net
157.240.28.15	A+PTR	edge-atlas-shv-01-den4.facebook.com
157.240.28.16	A+PTR	xx-fbcdn-shv-01-den4.fbcdn.net
157.240.28.16	A	scontent-den4-1.xx.fbcdn.net
157.240.28.18	A+PTR	edge-star-shv-01-den4.facebook.com
157.240.28.18	A	facebook.do
157.240.28.18	A	fbhome.cl
157.240.28.35	A+PTR	edge-star-mini-shv-01-den4.facebook.com
157.240.28.37	A	z-p15-scontent.cdninstagram.com
157.240.28.38	A+PTR	edge-sonar-mini-shv-01-den4.fbcdn.net
157.240.28.38	A	f212548a980kyyzaibi-gegjfiht1486419558-sonar.xx.fbcdn.net
157.240.28.38	A	f5676146e80-lqxcimsr1554737344-sonar.xz.fbcdn.net
157.240.28.48	PTR	edgeray-shv-01-den4.facebook.com
157.240.28.51	A+PTR	whatsapp-cdn-shv-01-den4.fbcdn.net
157.240.28.51	A	wa.me
157.240.28.51	A	media-den4-1.cdn.whatsapp.net
157.240.28.55	A	chat.cdn.whatsapp.net
157.240.28.57	A+PTR	edge-z-p3-shv-01-den4.facebook.com
157.240.28.57	A	z-p3-scontent-den4-1.xx.fbcdn.net
157.240.28.63	A+PTR	instagram-p3-shv-01-den4.fbcdn.net
157.240.28.63	A	scontent-den4-1.cdninstagram.com
157.240.28.174	A	z-p42-scontent.cdninstagram.com