Robtex

Up: 81.10.16.0/22
Can't show all results, try to descend to a more specific CIDR
Down left: 81.10.16.0/24
Down right: 81.10.17.0/24
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
81.10.16.250	PTR	host-81.10.16.250-static.tedata.net
81.10.16.250	A	mail.adew.org
81.10.16.251	PTR	host-81.10.16.251-static.tedata.net
81.10.16.251	A	mail.adew.org
81.10.16.253	A	alfaries.com
81.10.16.254	PTR	host-81.10.16.254-static.tedata.net
81.10.17.145	PTR	webmail.etg-eg.com
81.10.17.146	PTR	host-81.10.17.146-static.tedata.net
81.10.17.146	A	east-ag.com
81.10.17.146	A	mail.east-ag.com
81.10.17.242	PTR	mail.norpetco.com