Robtex

Up: 69.1.158.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 69.1.159.0/25
Down right: 69.1.159.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
69.1.159.248	PTR	smtp.inddc.com
69.1.159.248	A	relays.inddc.com
69.1.159.249	A+PTR	mail.inddc.com
69.1.159.249	A	relays.inddc.com
69.1.159.249	A	mail.customercenteredsolutions.com
69.1.159.250	A	mail.meetingbusinessneeds.com
69.1.159.252	A	smtp.inddc.com