Robtex

Up: 213.167.80.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 213.167.81.0/25
Down right: 213.167.81.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
213.167.81.5	A+PTR	qr-mimecast-81.foreshore.net
213.167.81.11	A+PTR	service2.mimecast-offshore.com
213.167.81.15	A	res2.mimecast-offshore.com
213.167.81.16	A+PTR	jer1-scan2.mimecast-offshore.com
213.167.81.17	PTR	service4.mimecast-offshore.com
213.167.81.18	A+PTR	service.mimecast-offshore.com
213.167.81.19	A+PTR	service6.mimecast-offshore.com
213.167.81.19	A	mail2.wq.bm
213.167.81.20	PTR	login.mimecast-offshore.com
213.167.81.20	A+PTR	webmail.mimecast-offshore.com
213.167.81.21	A+PTR	jer-api.mimecast.com
213.167.81.22	A+PTR	jer-api-1.mimecast-offshore.com
213.167.81.22	PTR	jer-api.mimecast-offshore.com
213.167.81.22	A+PTR	xdk.mimecast-offshore.com
213.167.81.23	A	mso4-b.mimecast-offshore.com
213.167.81.23	A	mso4.mimecast-offshore.com
213.167.81.24	PTR	off-smtp-1.mimecast-offshore.com
213.167.81.24	A+PTR	off-smtp-2.mimecast-offshore.com
213.167.81.25	A+PTR	je-smtp-delivery-1.mimecast-offshore.com
213.167.81.26	A+PTR	je-smtp-1.mimecast-offshore.com
213.167.81.26	A+PTR	je-smtp-2.mimecast-offshore.com
213.167.81.26	A	je-pop.mimecast-offshore.com
213.167.81.27	A+PTR	je-smtp-delivery-1.mimecast-offshore.com
213.167.81.28	A+PTR	je-smtp-delivery-2.mimecast-offshore.com
213.167.81.29	A+PTR	je-smtp-delivery-3.mimecast-offshore.com
213.167.81.30	A+PTR	je-smtp-delivery-4.mimecast-offshore.com
213.167.81.31	A+PTR	je-smtp-delivery-5.mimecast-offshore.com
213.167.81.32	A+PTR	je-smtp-delivery-6.mimecast-offshore.com
213.167.81.36	A+PTR	je-smtp-inbound-1.mimecast-offshore.com
213.167.81.36	A+PTR	je-smtp-inbound-2.mimecast-offshore.com
213.167.81.36	A	mail.toron.com
213.167.81.37	A+PTR	je-smtp-outbound-1.mimecast-offshore.com
213.167.81.37	A+PTR	je-smtp-outbound-2.mimecast-offshore.com
213.167.81.38	A+PTR	je-smtp-journal-1.mimecast-offshore.com
213.167.81.38	A+PTR	je-smtp-journal-2.mimecast-offshore.com
213.167.81.40	A+PTR	console-je.mimecast-offshore.com
213.167.81.41	A+PTR	je-smtp-o365-outbound-2.mimecast-offshore.com
213.167.81.41	A+PTR	je-smtp-o365-outbound-1.mimecast-offshore.com
213.167.81.57	A+PTR	je-smtp-delivery-17.mimecast-offshore.com
213.167.81.58	A+PTR	je-smtp-delivery-18.mimecast-offshore.com
213.167.81.248	A	je-smtp-delivery-18.mimecast-offshore.com