The PHPCounter reverse DNS and Whois tool looks up information about an IP address or a domain name.

For an Internet IP address of the form aaa.bbb.ccc.ddd, the tool resolves the address to host name by what is called a reverse DNS lookup. Also, it checks the whois database for the IP address to get information about the owner of the IP address.

For a domain name, the tool resolves the domain name to its IP address, and then checks the whois database for information about the IP address.