Summary:
The WhoIs database lists those entities (individuals/companies) that have registered domain names. Most Unix installations come with a command line program (whois) for querying this information. Alternatively, Network Solutions provide a Web interface at http://www.networksolutions.com/cgi-b in/whois/whois.
You can also find the owner of an IP address if you use this database.
Getting information on an IP Address
WhatIs is a search engine that has a similar name to WhoIs.
http://www.whois.sc provides an awesome search engines for looking up current and expired domain names and displaying them in color-coded output. It will also usually give whois info for an IP address (e.g, http://www.whois.sc/81.136.11.58).
Try also: http://samspade.org/t/lookat?a=000000 (replace 000000 with the number queried)
Before you get paranoic about IP addresses, checkout WhoIs. That will typically give you some information about an IP address, for example:
whois 81.136.11.58 % This is the RIPE Whois server. % The objects are in RPSL format. % % Rights restricted by copyright. % See http://www.ripe.net/ripencc/pub-services/db/copyright.html inetnum: 81.136.0.0 - 81.136.23.255 remarks: ******************************************************* remarks: * Please send abuse reports to abuse@btopenworld.com * remarks: ******************************************************* netname: BT-ADSL descr: IP Pools country: GB admin-c: BTOW1-RIPE tech-c: BTOW1-RIPE status: ASSIGNED PA mnt-by: BTNET-MNT mnt-lower: BTNET-MNT mnt-routes: BTNET-MNT changed: preston.dialip@bt.com 20031114 source: RIPE route: 81.128.0.0/11 descr: BT Public Internet Service origin: AS2856 mnt-by: BTNET-MNT changed: support@bt.net 20030615 source: RIPE role: BT OPENWORLD OPERATIONAL SUPPORT remarks: ******************************************************** remarks: * Please send abuse reports to abuse@btopenworld.com * remarks: * * remarks: ******************************************************** address: BT address: Openworld address: UK e-mail: ims.adastral@btopenworld.com admin-c: IT337-RIPE tech-c: RJG3-RIPE nic-hdl: BTOW1-RIPE mnt-by: BTNET-MNT changed: preston.dialip@bt.com 20030520 source: RIPE