Robtex

Up: 81.21.72.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 81.21.72.0/25
Down right: 81.21.72.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
81.21.72.1	PTR	fa1-0-10.cr1.donc.donhost.co.uk
81.21.72.2	PTR	fa0-0-10.cr2.donc.donhost.co.uk
81.21.72.3	PTR	hs10.donc.donhost.co.uk
81.21.72.4	A+PTR	amanda2.donc.donhost.co.uk
81.21.72.5	PTR	server22.donhost.co.uk
81.21.72.19	A	www.bowerandsmith.co.uk
81.21.72.19	A	networking.sportbusiness.com
81.21.72.28	PTR	dedicated.parosweb.org
81.21.72.30	A+PTR	ds9543.dedicated.turbodns.co.uk
81.21.72.30	A	ns1.future1.co.uk
81.21.72.31	PTR	ds9543.dedicated.turbodns.co.uk
81.21.72.31	A	ns2.future1.co.uk
81.21.72.31	A	adtruck.co.uk
81.21.72.38	PTR	ds580.dedicated.turbodns.co.uk
81.21.72.43	A	hostmaster.ptmy.net
81.21.72.43	A	mcfltd.net
81.21.72.43	A	efrank.co.uk
81.21.72.47	A	hostmaster.govnet-intranet.net
81.21.72.47	A	govnet-intranet.net
81.21.72.47	A	sipsevents.co.uk
81.21.72.51	A	simplified-challenge.com
81.21.72.64	A	ns1.absolutewebhosting.co.uk
81.21.72.70	PTR	ds682.dedicated.turbodns.co.uk
81.21.72.77	PTR	ds501.dedicated.turbodns.co.uk
81.21.72.84	A+PTR	ds9542.dedicated.turbodns.co.uk
81.21.72.85	PTR	ds9542.dedicated.turbodns.co.uk
81.21.72.90	A	ns1.fcsnooker.co.uk
81.21.72.91	A	ns2.fcsnooker.co.uk
81.21.72.96	PTR	ds9542.dedicated.turbodns.co.uk
81.21.72.98	PTR	ds585.dedicated.turbodns.co.uk
81.21.72.98	A	ds9531.dedicated.turbodns.co.uk
81.21.72.99	PTR	ds9531.dedicated.turbodns.co.uk
81.21.72.99	A	*.encounter-overland.com
81.21.72.99	A	*.encounteroverland.com
81.21.72.100	PTR	server749.dedicated.webfusion.co.uk
81.21.72.102	PTR	server749.dedicated.webfusion.co.uk
81.21.72.103	PTR	ds9555.dedicated.turbodns.co.uk
81.21.72.104	PTR	server749.dedicated.webfusion.co.uk
81.21.72.106	A	db.bymailonsunday.com
81.21.72.107	A	cdbymailonsunday.com
81.21.72.107	A	dvdbymailonsunday.com
81.21.72.107	A	moviesbymailonsunday.com
81.21.72.109	PTR	ds585.dedicated.turbodns.co.uk
81.21.72.114	PTR	ds9555.dedicated.turbodns.co.uk
81.21.72.116	PTR	ds501.dedicated.turbodns.co.uk
81.21.72.124	PTR	ds820.dedicated.turbodns.co.uk
81.21.72.133	PTR	ds820.dedicated.turbodns.co.uk
81.21.72.141	PTR	ds9555.dedicated.turbodns.co.uk
81.21.72.143	PTR	ds501.dedicated.turbodns.co.uk
81.21.72.144	PTR	ds820.dedicated.turbodns.co.uk
81.21.72.155	PTR	ds820.dedicated.turbodns.co.uk
81.21.72.157	PTR	ds9555.dedicated.turbodns.co.uk
81.21.72.158	PTR	ds820.dedicated.turbodns.co.uk
81.21.72.171	A+PTR	server564.dedicated.webfusion.co.uk
81.21.72.172	PTR	server564.dedicated.webfusion.co.uk
81.21.72.172	A	mail.angliapartitions.net
81.21.72.174	PTR	ds9555.dedicated.turbodns.co.uk
81.21.72.177	A+PTR	ds9555.dedicated.turbodns.co.uk
81.21.72.178	PTR	ds9555.dedicated.turbodns.co.uk
81.21.72.178	A	www.morecambebay.co.uk
81.21.72.179	PTR	ds820.dedicated.turbodns.co.uk
81.21.72.190	PTR	ds501.dedicated.turbodns.co.uk
81.21.72.193	A	ns1.secure-area.net.20061223091117.deleted.gkg.net
81.21.72.193	A	ns2.secure-area.net.20061223091109.deleted.gkg.net
81.21.72.199	PTR	ds468.dedicated.turbodns.co.uk
81.21.72.209	PTR	ds501.dedicated.turbodns.co.uk
81.21.72.223	A+PTR	ds9544.dedicated.turbodns.co.uk
81.21.72.224	PTR	ds9544.dedicated.turbodns.co.uk
81.21.72.235	PTR	ds681.dedicated.turbodns.co.uk
81.21.72.235	A	ns1.sparksautoelectrical.co.uk
81.21.72.235	A	ns1.mousehouse-uk.com
81.21.72.236	PTR	ds681.dedicated.turbodns.co.uk
81.21.72.236	A	ns2.expresssignsbristol.co.uk
81.21.72.236	A	sparksautoelectrical.co.uk
81.21.72.237	PTR	ns1.futuroeglobal.com
81.21.72.238	PTR	ns2.futuroeglobal.com
81.21.72.238	A	ramsimports.net
81.21.72.238	A	www.lightpro.com
81.21.72.245	PTR	ds9544.dedicated.turbodns.co.uk
81.21.72.246	PTR	ds9544.dedicated.turbodns.co.uk
81.21.72.249	A+PTR	ds5522.dedicated.turbodns.co.uk
81.21.72.250	PTR	ds5522.dedicated.turbodns.co.uk
81.21.72.252	A	unihold.co.za