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.

Read Also: 10 Linux Dig (Domain Information Groper) Commands to Query DNS

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.

$ whois 216.58.206.46 # # ARIN WHOIS data and services are subject to the Terms of Use # available at: https://www.arin.net/whois_tou.html # # If you see inaccuracies in the results, please report at # https://www.arin.net/public/whoisinaccuracy/index.xhtml # # # The following results may also be obtained via: # https://whois.arin.net/rest/nets;q=216.58.206.46?showDetails=true&showARIN=false&showNonArinTopLevelNet=false&ext=netref2 # NetRange: 216.58.192.0 - 216.58.223.255 CIDR: 216.58.192.0/19 NetName: GOOGLE NetHandle: NET-216-58-192-0-1 Parent: NET216 (NET-216-0-0-0-0) NetType: Direct Allocation OriginAS: AS15169 Organization: Google LLC (GOGL) RegDate: 2012-01-27 Updated: 2012-01-27 Ref: https://whois.arin.net/rest/net/NET-216-58-192-0-1 OrgName: Google LLC OrgId: GOGL Address: 1600 Amphitheatre Parkway City: Mountain View StateProv: CA PostalCode: 94043 Country: US RegDate: 2000-03-30 Updated: 2017-12-21 Ref: https://whois.arin.net/rest/org/GOGL ...

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: [email protected] 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 ....

The formatting of information will differ based on the WHOIS server used. In addition, one downside of WHOIS is the lack of full access to the data, therefore check out these useful guides for querying DNS information in Linux:

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