WHOIS is network protocol use in internet for searching domain names, IP addresses and network servers. This is an independent service, supports by independent internet protocol. One WHOIS server saved database with names, email addresses, phone numbers of registеred users. Access to the database is for free and it's accomplished with WHOIS client via WHOIS protocol.
If you fear for discredit of your private data, the global administrators suggest service Privacy Protect, with which help your private data will not showing up in the public database of WHOIS. Your data is accessible only from organizations operating with domain names.
There are many WHOIS servers in the world, and howsoever if your Internet provider doesn't support WHOIS server, you can ask the database on this internet address: Whois - check domain name