WHOIS is a TCP-based query and response protocol that is commonly used to provide information services to Internet users. It returns information about the registered Domain Names, an IP address block, Name Servers and a much wider range of information services.
In Linux, the whois command line utility is a WHOIS client for communicating with the WHOIS server (or database host) which listen to requests on the well-known port number 43, which stores and delivers database content in a human-readable format.
whois command line utility does not come pre-installed on many Linux distributions, run the appropriate command below for your distribution to install it.
# yum install whois #RHEL/CentOS # dnf install whois #Fedora 22+ $ sudo apt install whois #Debian/Ubuntu
How to Find IP Address Information
To get the information about specific IP Address issue the command as shown in the below example.
How to Find Domain Information
To get the information about the registered domain, simply issue the following command with the domain name. It will retrieve domain data including availability, ownership, creation, expiration details, name servers, etc.
$ whois google.com Domain Name: GOOGLE.COM Registry Domain ID: 2138514_DOMAIN_COM-VRSN Registrar WHOIS Server: whois.markmonitor.com Registrar URL: http://www.markmonitor.com Updated Date: 2011-07-20T16:55:31Z Creation Date: 1997-09-15T04:00:00Z Registry Expiry Date: 2020-09-14T04:00:00Z Registrar: MarkMonitor Inc. Registrar IANA ID: 292 Registrar Abuse Contact Email: firstname.lastname@example.org Registrar Abuse Contact Phone: +1.2083895740 Domain Status: clientDeleteProhibited https://icann.org/epp#clientDeleteProhibited Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited Domain Status: serverDeleteProhibited https://icann.org/epp#serverDeleteProhibited Domain Status: serverTransferProhibited https://icann.org/epp#serverTransferProhibited Domain Status: serverUpdateProhibited https://icann.org/epp#serverUpdateProhibited Name Server: NS1.GOOGLE.COM Name Server: NS2.GOOGLE.COM Name Server: NS3.GOOGLE.COM Name Server: NS4.GOOGLE.COM ....