Robtex

Up: 91.239.40.0/22
Can't show all results, try to descend to a more specific CIDR
Down left: 91.239.42.0/24
Down right: 91.239.43.0/24

IP	Type	Hostname
91.239.43.35	PTR	mx65.sendpulse.info
91.239.43.36	A+PTR	mx66.sendpulse.info
91.239.43.42	PTR	mx72.sendpulse.info
91.239.43.64	PTR	mx94.sendpulse.info
91.239.43.79	PTR	mx109.sendpulse.info
91.239.43.80	PTR	mx110.sendpulse.info
91.239.43.90	PTR	mx120.sendpulse.info
91.239.43.91	PTR	mx121.sendpulse.info
91.239.43.92	PTR	mx122.sendpulse.info
91.239.43.95	PTR	mx125.sendpulse.info
91.239.43.98	PTR	mx128.sendpulse.info
91.239.43.101	PTR	mx1.smtp.send-box.ru
91.239.43.147	PTR	mx191.pulsesmtp.com
91.239.43.162	PTR	mx206.pulsesmtp.com
91.239.43.191	PTR	mx235.pulsesmtp.com
91.239.43.197	PTR	mx241.pulsesmtp.com
91.239.43.215	A+PTR	mx31.smtp.send-box.ru
91.239.43.215	A	mx31.news.ozon.ru
91.239.43.216	A+PTR	mx32.smtp.send-box.ru
91.239.43.216	A	mx32.news.ozon.ru
91.239.43.217	A+PTR	mx33.smtp.send-box.ru
91.239.43.217	A	mx33.news.ozon.ru
91.239.43.218	A+PTR	mx34.smtp.send-box.ru
91.239.43.218	A	mx34.news.ozon.ru
91.239.43.219	A+PTR	mx35.smtp.send-box.ru
91.239.43.219	A	mx35.news.ozon.ru
91.239.43.220	A+PTR	mx36.smtp.send-box.ru
91.239.43.220	A	mx36.news.ozon.ru
91.239.43.221	A+PTR	mx37.smtp.send-box.ru
91.239.43.221	A	mx37.news.ozon.ru
91.239.43.222	A+PTR	mx38.smtp.send-box.ru
91.239.43.222	A	mx38.news.ozon.ru
91.239.43.223	A+PTR	mx39.smtp.send-box.ru
91.239.43.223	A	mx39.news.ozon.ru
91.239.43.224	A+PTR	mx40.smtp.send-box.ru
91.239.43.224	A	mx40.news.ozon.ru
91.239.43.225	A+PTR	mx41.smtp.send-box.ru
91.239.43.225	A	mx41.news.ozon.ru
91.239.43.226	A+PTR	mx42.smtp.send-box.ru
91.239.43.226	A	mx42.news.ozon.ru
91.239.43.227	PTR	mx0.routee.me
91.239.43.228	PTR	mx1.routee.me