A simple but effective means for collecting additional information about our target is Whois. The Whois service allow us to access specific information about our target including the IP addresses or host names of the company's Domain Name System (DNS) server and contact information which usually contain an address and phone number.
Whois is built into the Linux Operating System. The simplest way to use this service is to open a terminal and enter the command:-"whois target_domain" .For example we have to find out information about computerweb, we would issue the command:-"whois computerweb.ooo". It is important to record all the information and pay special attention to the DNS server. If the DNS servers are listed by name only,we will use the Host command to translate those name into IP addresses("host target_hostname", we can also translate IP address to host name using the command:-"host IP_address").


  We can also use a web browser to search Whois. By navigating to https://www.whois.com/, you can search your target in the "WHOIS Lookup".