Robtex

Up: 178.248.40.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 178.248.40.0/23
Down right: 178.248.42.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
178.248.40.12	PTR	int0.client.access.fanaptelecom.net
178.248.40.50	PTR	int0.client.access.fanaptelecom.net
178.248.40.186	PTR	int0.client.access.fanaptelecom.net
178.248.41.50	PTR	broadband.customer.azadnet.net
178.248.41.50	A	mail2.pkc-ir.com
178.248.41.53	PTR	broadband.customer.azadnet.net
178.248.41.53	A	mail.pkc-ir.com
178.248.41.118	PTR	broadband.customer.azadnet.net
178.248.41.214	PTR	int0.client.access.fanaptelecom.net
178.248.41.214	A	msqi.ir
178.248.41.243	PTR	broadband.customer.azadnet.net
178.248.41.243	A	ns1.jooya.ir
178.248.41.243	A	ns1.jouya.ir
178.248.41.247	A+PTR	mail.ghazaldamon.com
178.248.41.247	A	mail2.ghazaldamon.com
178.248.41.254	PTR	broadband.customer.azadnet.net
178.248.42.35	PTR	int0.client.access.azadnet.net
178.248.42.35	A	mail.gcdc.ir
178.248.42.61	PTR	bblmail.bbl-marine.com
178.248.42.98	A	www.pgpicc.com
178.248.42.99	PTR	int0.client.access.fanaptelecom.net
178.248.42.99	A	edgemail.frontierpetro.com
178.248.42.99	A	edgemail.pvcwestco.com
178.248.42.106	PTR	int0.client.access.fanaptelecom.net
178.248.42.166	PTR	int0.client.access.fanaptelecom.net
178.248.42.178	PTR	int0.client.access.fanaptelecom.net
178.248.42.194	PTR	int0.client.access.fanaptelecom.net
178.248.42.194	A	mail.tbt.ir
178.248.42.210	A	mail.omv.co.ir
178.248.42.210	A	omv.co.ir
178.248.42.210	A	mx1.omv.co.ir
178.248.42.219	PTR	int0.client.access.fanaptelecom.net
178.248.43.102	PTR	int0.client.access.fanaptelecom.net
178.248.43.106	PTR	broadband.customer.azadnet.net
178.248.43.117	PTR	int0.client.access.fanaptelecom.net
178.248.43.117	A	hostmaster.iraneit.com
178.248.43.117	A	mail.karanegar.ir
178.248.43.230	PTR	int0.client.access.fanaptelecom.net
178.248.43.230	A	mail.tejaratp.com
178.248.43.255	PTR	broadband.customer.azadnet.net