The Purpose of WHOIS Databases
Information about domains is stored in WHOIS databases, which are overseen but not managed by the Internet Corporation for Assigned Names and Numbers (ICANN). If you want to know who owns a website or to contact them, or perhaps to report a stolen contact or to inquire about advertising, you can use the WHOIS search to find that information. The search engine will then perform a WHOIS database download of the information requested. The precise format of the results depends on the search engine, but all search engines can look up and display that data.
Similarly, users can look you up if you own a website. This listing can include contact details for various people, including the persons in charge of billing and tech support, among other positions. You can prevent people from finding that information by enabling WHOIS privacy for your domain.
When is the Database Updated
When a website changes hands or someone else becomes responsible for a specific department, you'll want to update the database. If you wish to change that information, you can do so with your domain registrar, which may be your hosting company if you purchased both services from the same company, and not ICANN. Whenever a website is registered or WHOIS information is changed, the corresponding details must be added or changed within the database. This process can take up to 48 hours, so your changes may not be immediately available.
There are different WHOIS databases, and they may not all update at the same time. For example, using the database provided by your registrar is likely to show updated information before other databases do.
Website owners will receive confirmation emails whenever any changes are made to their listing in the database. This not only confirms that you've successfully made a change but can alert you if someone is attempting to change your WHOIS information without your permission.
WHOIS Information Versus DNS Caches
These databases should not be confused with the caches that store the necessary information to load a website. Each friendly domain name is associated with the IP address of the server that houses that domain. That DNS information is stored on your computer as well as by every Internet Service Provider.
DNS information does update after WHOIS changes, but it can also update for other reasons such as a domain registration or transfer to a different company, which do not require a WHOIS database download. It can take up to 72 hours – although it's often quicker – for those caches to refresh. This is known as domain propagation and is an issue that many website owners have to face. Some users may be able to access a website sooner because their Internet Service Providers refresh those caches more frequently.
The time of propagation depends on each domain's Time to Live or TTL value, a setting that instructs Internet Service Providers to update the cache of DNS information periodically. You can update your domain's TTL value before making changes to reduce any downtime your site might experience.