but there are other ways..
quite simple too (to see who is actually providing the dataservices/upstream for the domain:
do a ping to the domain, fetch the IP address
or do a nslookup the reverse record associated with the ip address.
(e.g. a domain can be bonded to an IP address, which itself is officially bonded to another (sub)domain.
since the ipaddress is not owned by the domain host itself, but by the provider.
then go to (for europe based addresses):
or go to (for american bases addresses):
or go to (Latin American / Caribbean addresses):
or go to (Asia / Pacific addresses):
or go to (African addresses):
in either of these search engines, type the ip address, and it will come back with a result.
(if it's found in the database, if not, you need to go to another search from the one i mentioned)
the result should contain a netblock/inetnum (pool of ipaddresses, a.k.a Assigned PA/PI space)
and address information.