go
bom3.bom.gov.au has one IP number , which also has a corresponding reverse pointer. wa.bom.gov.au, 6.178.134.in-addr.arpa, 118.178.134.in-addr.arpa and 253.178.134.in-addr.arpa use this as a nameserver. bom.gov.au is a domain controlled by three nameservers. All of them are on different IP networks. Incoming mail for bom.gov.au is handled by two mailservers at bom.gov.au themselves. They are on different IP networks. bom3.bom.gov.au is hosted on a server in Australia.

bom3.bom.gov.au
a records
 
+ 134.178.140.211 134.178.128.0/17 AS23667 -
+ --- -

bom.gov.au
ns-soa records
ho-dns-ext.bom.gov.au
+ 134.178.63.126 134.178.0.0/17 AS23667 -
+ --- -
ns records
ns1.unimelb.edu.au
+ 128.250.20.2 128.250.0.0/16 AS10148 -
+ --- -
drs-dns-ext.bom.gov.au
+ 134.178.253.126 134.178.128.0/17 AS23667 -
ho-dns-ext.bom.gov.au
+ 134.178.63.126 134.178.0.0/17 AS23667 -
mx records
drs-mailfilter2.bom.gov.au
+ 134.178.253.184 134.178.128.0/17 AS23667  
+ ---  
ho-mailfilter2.bom.gov.au
+ 134.178.63.184 134.178.0.0/17 AS23667  
ip numbers of host
134.178.140.211
ptrs of ip numbers
bom3.bom.gov.au
ip numbers using ptr to this host
134.178.140.211
domains using this as nameserver
118.178.134.in-addr.arpa
253.178.134.in-addr.arpa
6.178.134.in-addr.arpa
wa.bom.gov.au
used as nameserver but missing in parent delegation
118.178.134.in-addr.arpa
wa.bom.gov.au