Whois displays the registrar information from a given domain. Additionally all IP addresses and aliases of the domain will be shown.
The Whois tool supports Internationalized Domain Names (IDN).
Note: From one IP address 5 requests per day are allowed.
Some Whois servers no longer provide information when too many requests are received. In this case, repeated requests are counterproductive.
Hint: You can make Whois queries with the freeware application eToolz too.