WHOIS
There are two methods to connect website, using IP or hostname (more information you can find: Lookup IP). But you can know more about owners of website. You can use WHOIS service. WHOIS service is public and free. All domains registrar must public information about domain owners (but you can buy "privace service"). There are many websites, were you can check WHOIS information. This is another place. I trying to place on this website all tools I need every day in my job.
WHOIS service working on port 43. Simples tool you can use to receive information is whois command on Linux.
Documentation: RFC 3912: WHOIS Protocol Specification
Help file can be obtained with the LINUX command:
# whois -h whois.ripe.net HELP
