Description: Root DNS servers are the top-level DNS servers that contain information about the root zone and direct queries to the appropriate top-level domain servers. These servers are fundamental to the functioning of the Internet, as they act as the first point of contact in the domain name system (DNS) hierarchy. When a user enters a URL in their browser, the query is sent to a DNS server, which may not have the necessary information. In this case, the DNS server queries one of the root servers to obtain the IP address corresponding to the requested domain. Root DNS servers are responsible for maintaining information about top-level domains such as .com, .org, and .net, and redirect queries to the DNS servers that manage those specific domains. There are 13 root servers, identified by letters A through M, and they are globally distributed to ensure redundancy and availability. This hierarchical and distributed structure allows the DNS system to be scalable and fault-tolerant, which is essential for the stability and performance of the Internet as a whole.
History: Root DNS servers were established in 1984 as part of the development of the domain name system (DNS) by Paul Mockapetris. Since then, they have evolved to accommodate the exponential growth of the Internet. In 1997, the system of 13 root servers was implemented, which has largely remained intact, although replicas and additional servers have been added to improve resilience and response speed.
Uses: Root DNS servers are primarily used to resolve domain name queries to IP addresses. They are essential for web browsing, email, and other online services, as they allow users to access websites using readable names instead of numerical IP addresses.
Examples: An example of the use of root DNS servers is when a user tries to access ‘www.example.com’. If the local DNS server does not have the IP address, it queries a root server, which redirects the query to the DNS server managing the ‘example.com’ domain.
