go
ns2.dci.ir has one IP number , which also has a corresponding reverse pointer. ezaam.com, azad.ac.ir and itcmplsportal.ir use this as a nameserver. dci.ir is a domain controlled by two nameservers at dci.ir themselves. They are on different IP networks. Incoming mail for dci.ir is handled by one mailserver also at dci.ir. ns2.dci.ir is hosted on a server in Iran.

ns2.dci.ir
a records
 
+ 217.218.127.105 217.218.0.0/17 AS12880 -
+ --- -

dci.ir
ns-soa records
ns1.dci.ir
+ 217.218.127.104 217.218.0.0/17 AS12880 -
+ --- -
ns records
ns1.dci.ir
+ 217.218.127.104 217.218.0.0/17 AS12880 -
+ --- -
ns4.dci.ir
+ 217.218.155.104 217.218.154.0/23 AS12880  
+ ---  
mx records
mail.dci.ir
+ 217.218.127.122 217.218.0.0/17 AS12880 -
+ --- -
ip numbers of host
217.218.127.105
ptrs of ip numbers
ns2.dci.ir
ip numbers using ptr to this host
217.218.127.105
domains using this as nameserver
azad.ac.ir
ezaam.com
itcmplsportal.ir
used as nameserver but missing in parent delegation
azad.ac.ir
used as nameserver but missing in zone
ezaam.com
itcmplsportal.ir