Research Clinic
supporting open source investigation

Who owns a domain ("whois")?
Amazingly flexible domain information database.
Researchclinic's Reverse Whois Search
Search various Whois sites for details that might be in a domain registration (email, phone number, postcode)
is a great Whois tool with superb extras available by subscription. See also
This allows you to do a free search for domains by email.
Website Informer
allows various fields and keywords to be searched.

See web ownership connections
Netcomber - a nice graphical interface looks at domain ownership and shows relationships between sites.

paid service, but contains a huge range of domain, dns and ip investigative tools
What's on the server? ("Reverse IP")
"Reverse IP", lists domains it believes are sharing a server. See also spyonweb and webhosting
Recommended, with many different functions
Domaintools (subscribers)
Highly recommended, but not free.
Really useful tool for investigating a domain. Finds its subdomains etc.
Netcraft report
Click site report for WHOIS, then "netblock owner".
List subdomains on a site
See also intellitamper, foca and acunetix  software
Pentest Tools
Finds hidden (?) subdomains
Reverse Internet
Also allows you to check neighbouring domains.
Hurricane Electric
Investigate a domain name and its IP address block.
Historical whois
Domaintools (subscribers) archive (free)
Specialist IP address tools
Look up a website's IP address with IP Tracker - see also and Findip-Address Geotrace an IP Address
Locate an IP address down to the users home town!
See also Max Mind and Whatismyipaddress
Various IP location & whois tools from an Austrian site. Sometimes finds details that others miss.
Trace Route
YouGetSignal Geographically trace a server containing a Web page or allocated an IP address.
Email tracer 
(use with caution!)
See also ip-address, mxtoolbox, reversemx and network-tools
DNS Stuff
Various tools to probe a server.
How popular is a domain?
Webrank stats


International WHOIS/IP research
International IPs
Find which regional authority handles IP address allocation for a country. 
National Authorities
International bodies that issue country code domains. If WHOIS fails, go to the source! 
See also IANA
Generic Domains
Authorities for domains that don't have a country code or
standard top level domain.
British domain authority who
oversee the .uk domain names
The TV Corp. 
WHOIS for the .tv domain.
See also DotFM WHOIS for the .fm domain
IP authority for the Asia Pacific region.
The IP issuing authority for Europe, have the best WHOIS lookup for European IP addresses.
IP authority for for North America 
for Latin America & the Caribbean and AFRINIC for Africa


(c) Paul Myers 2014. The views expressed on this site are the author's own. The links do not represent an endorsement.
altered banner image (c) Jan Krömer, used with gratitude via creative commons license