Robtex

Up: 173.242.24.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 173.242.25.0/25
Down right: 173.242.25.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
173.242.25.1	PTR	173.242.25.1.static.greenhousedata.net
173.242.25.1	A	mx.goclicklead.com
173.242.25.1	A	mx.newswiregeniusemail.com
173.242.25.2	A	cloud2.clickbackmail.com
173.242.25.3	A	mikebinding.com
173.242.25.3	A	cloud3.clickbackmail.com
173.242.25.5	A	cloud5.clickbackmail.com
173.242.25.7	A	cloud7.clickbackmail.com
173.242.25.8	A	mx.cbsalesrep.com
173.242.25.8	A	mx.execteamcb.com
173.242.25.8	A	mx.clickbackteamexec.com
173.242.25.9	A	cloud9.clickbackmail.com
173.242.25.11	PTR	173.242.25.11.static.greenhousedata.net
173.242.25.11	A	cloud11.clickbackmail.com
173.242.25.12	A	cloud12.clickbackmail.com
173.242.25.13	PTR	173.242.25.13.static.greenhousedata.net
173.242.25.13	A	cloud13.clickbackmail.com
173.242.25.15	PTR	173.242.25.15.static.greenhousedata.net
173.242.25.15	A	cloud15.clickbackmail.com
173.242.25.16	PTR	173.242.25.16.static.greenhousedata.net
173.242.25.16	A	cloud16.clickbackmail.com
173.242.25.17	A	cloud17.clickbackmail.com
173.242.25.23	A	cloud23.clickbackmail.com
173.242.25.27	PTR	cloud27.clickbackmail.com
173.242.25.30	PTR	173.242.25.30.static.greenhousedata.net
173.242.25.30	A	cloud30.clickbackmail.com
173.242.25.87	PTR	173.242.25.87.static.greenhousedata.net
173.242.25.138	A	smtp.dataservreg72.com
173.242.25.141	A	smtp.dataservreg75.com
173.242.25.142	A	smtp.dataservreg76.com
173.242.25.145	A	smtp.dataservreg79.com
173.242.25.146	A	smtp.dataservreg80.com
173.242.25.151	A	smtp.dataservreg85.com
173.242.25.170	A	smtp.dataservreg104.com
173.242.25.171	A	smtp.dataservreg105.com
173.242.25.172	PTR	173.242.25.172.static.greenhousedata.net
173.242.25.172	A	mx.salescbrep.com
173.242.25.173	A	smtp.dataservreg107.com
173.242.25.176	PTR	173.242.25.176.static.greenhousedata.net
173.242.25.176	A	smtp.dataservreg110.com
173.242.25.184	A	smtp.dataservreg118.com
173.242.25.187	A+PTR	smtp.dataservreg121.com
173.242.25.205	PTR	173.242.25.205.static.greenhousedata.net