Robtex

Up: 123.231.240.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 123.231.240.0/23
Down right: 123.231.242.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
123.231.240.26	A	mail.i3networksecurity.com
123.231.240.28	A+PTR	mail.bumida.co.id
123.231.240.28	A	webmail.bumida.co.id
123.231.240.29	A+PTR	esa.bumida.co.id
123.231.240.242	A+PTR	mx2.olympindo.co.id
123.231.240.243	A+PTR	mx3.olympindo.co.id
123.231.240.243	A	ns2.olympindo.co.id
123.231.240.244	A+PTR	mx1.olympindo.co.id
123.231.240.244	A	ns1.olympindo.co.id
123.231.241.30	A	gtm1.saptaindra.co.id
123.231.241.43	PTR	mail.sentosagroup.com
123.231.241.43	A	mail.tbsgroup.co.id
123.231.241.43	A	mail2.luleyhotels.com
123.231.241.53	A+PTR	singkawang.mtf.co.id
123.231.241.53	A	mx10.mtf.co.id
123.231.241.57	A+PTR	mx5.mtf.co.id
123.231.241.62	A+PTR	webmail.mtf.co.id
123.231.241.77	A	jktowa.iom.or.id
123.231.241.194	A	lgilink.com
123.231.241.237	A	raharja-net.co.id
123.231.242.29	PTR	www.garudaceramics.com
123.231.242.34	PTR	multistructure.co.id
123.231.242.34	A	mx2.multistructure.co.id
123.231.242.34	A	www.into-club.org
123.231.242.35	PTR	multistructure.co.id
123.231.242.108	A	mail.kerosene-stoves.com
123.231.242.108	A	kerosene-stoves.com
123.231.242.147	A	ns1.bmaks.net
123.231.242.149	A	ns2.b-maks.com
123.231.243.62	A	mail.tribunsumsel.com
123.231.243.133	A+PTR	mx2.wilmar.co.id
123.231.243.134	A+PTR	mail.insurindo.com
123.231.243.135	A	mx2.dutasugar.co.id
123.231.243.135	A	mx2.insurindo.com
123.231.243.137	A+PTR	mail.usdaseroja.com
123.231.243.137	A	server.usdaseroja.com
123.231.243.137	A	mail.jawamanis.com
123.231.243.138	A+PTR	mail.tm.co.id
123.231.243.140	PTR	mail.wilmar.co.id
123.231.243.140	A	mail2.wilmar.co.id
123.231.243.140	A	mx4.wilmar.co.id
123.231.243.141	PTR	mail.dutasugar.co.id
123.231.243.187	A	mail.disdikmedan.com