whois is a command-line tool in Kali Linux used to gather information about domain names, IP addresses, or autonomous systems by querying the WHOIS database. It provides details such as domain registration information, registrant details, the creation and expiration dates of a domain, nameservers, and the organization associated with an IP address.

Key Features:

• Retrieves information about domain ownership and registration.
• Provides contact details for domain administrators and technical personnel.
• Offers details on domain expiration, update history, and status.
• Queries information related to IP addresses, such as associated ISP and organization.

Common whois Commands:

whois <domain-name>

whois example.com

whois <ip-address>

whois -h whois.iana.org <tld>

whois -h <whois-server> <domain-name/>

Use Cases:

• Domain Ownership Verification: Used to identify the owner of a domain and their contact information.
• Investigation of Suspicious Domains: Helps to find information about potentially malicious domains or IP addresses.
• Tracking Domain Expirations: Useful for checking the expiration dates of domains to track when they will become available.
• Penetration Testing Reconnaissance: Provides critical information about domain infrastructure during the reconnaissance phase of security assessments.

The whois tool is simple yet powerful for gathering registration and administrative details about domains and IP addresses, making it essential in both network administration and penetration testing.