Robtex

Up: 50.115.212.0/22
Can't show all results, try to descend to a more specific CIDR
Down left: 50.115.212.0/24
Down right: 50.115.213.0/24
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
50.115.213.6	PTR	inbound-smtp-lup1.r.grouponmail.com
50.115.213.6	A	r.grouponmail.com
50.115.213.6	A	grouponmail.ch
50.115.213.9	A	country-vip.groupon.fr
50.115.213.47	A	t.groupon.ca
50.115.213.47	A	country-vip.groupon.ca
50.115.213.55	A	www.grouponviajes.es
50.115.213.102	A	pcs-int.groupon.com