Robtex

Up: 199.44.158.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 199.44.159.0/25
Down right: 199.44.159.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
199.44.159.10	PTR	sametime.mainline.com
199.44.159.11	PTR	webcast2.mainline.com
199.44.159.15	PTR	deployment.mainline.com
199.44.159.31	PTR	blackhole.mainline.com
199.44.159.33	PTR	traveler-backend2.mainline.com
199.44.159.50	PTR	itads.mainline.com
199.44.159.53	A+PTR	charon.mainline.com
199.44.159.54	PTR	oberon.summiteast.com
199.44.159.55	PTR	dev.mainline.com
199.44.159.57	A+PTR	ganymede.mainline.com
199.44.159.58	A	mainlineasp.com
199.44.159.61	A+PTR	juliet.mainline.com
199.44.159.62	PTR	snapdev.mainline.com
199.44.159.63	PTR	snapprod.mainline.com
199.44.159.67	A+PTR	dropbox.mainline.com
199.44.159.71	PTR	solvit-gw.mainline.com
199.44.159.74	PTR	tally4.mainline.com
199.44.159.75	PTR	devdocstore-win.mainline.com.159.44.199.in-addr.arpa
199.44.159.76	PTR	devdocstore.mainline.com.159.44.199.in-addr.arpa
199.44.159.80	PTR	ebetterplace.com
199.44.159.90	PTR	semhome.summiteast.com
199.44.159.91	A+PTR	mailhosting.mainline.com
199.44.159.124	PTR	stmux.mainline.com
199.44.159.125	A	calisto.mainline.com
199.44.159.126	PTR	stmux2.mainline.com
199.44.159.130	PTR	cognos-vg01.mainline.com
199.44.159.146	PTR	mail.mainlineasp.com
199.44.159.152	PTR	luna.mainline.com
199.44.159.160	PTR	stmedia.mainline.com
199.44.159.161	PTR	stmeeting.mainline.com
199.44.159.162	PTR	stproxy1.mainline.com
199.44.159.163	PTR	stproxy2.mainline.com
199.44.159.177	PTR	mail.mainlineasp.com
199.44.159.177	A	mail.summitinternationalgroup.com
199.44.159.177	A	mail.vision2020funds.com