Robtex

Up: 193.106.16.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 193.106.16.0/23
Down right: 193.106.18.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
193.106.16.16	PTR	ns1.pbx-network.de
193.106.16.50	A	cloud-pbx.de
193.106.16.103	A	srv01.pbx-network.de
193.106.16.104	A	ast04.pbx-network.de
193.106.16.107	A+PTR	ast03.pbx-network.de
193.106.16.228	A	yoofon.de
193.106.16.229	PTR	www01.pbx-network.de
193.106.16.229	A	pixima.de
193.106.16.229	A	pbxnetwork.de
193.106.16.230	PTR	fax-gw.pbx-network.de
193.106.16.234	A+PTR	app02.pbx-network.de
193.106.16.234	A	secure.pbx-network.de
193.106.16.235	PTR	www02.pbx-network.de
193.106.16.235	A	personal-voip.ch
193.106.16.235	A	voicetermination.de
193.106.19.63	A	mail.schuebel.biz
193.106.19.250	A+PTR	mail.xbo.de
193.106.19.250	A	mail.webkfz.de