Robtex

Up: 216.52.142.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 216.52.142.0/25
Down right: 216.52.142.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
216.52.142.30	A+PTR	ns1.williamblair.com
216.52.142.54	PTR	smtp3.williamblair.com
216.52.142.54	A	smtp1.williamblair.com
216.52.142.54	A	smtp2.williamblair.com
216.52.142.55	A+PTR	smtp4.williamblair.com
216.52.142.63	A	www.wbremote.com
216.52.142.63	A	wbremote.com
216.52.142.98	A+PTR	riva.williamblair.com
216.52.142.100	A	rdocs.com
216.52.142.100	A	www.rdocs.com
216.52.142.103	A	selectinvestmentpartners.com
216.52.142.103	A	selectpartners.net
216.52.142.103	A	williamblairselect.com
216.52.142.170	A	ftp.williamblair.com
216.52.142.201	A	wbsip.williamblair.com