In the vast ecosystem of the Internet, Domain Name System (DNS) root servers stand as the foundational pillars that facilitate the efficient resolution of domain names to their corresponding IP addresses. These servers are crucial components of the DNS infrastructure, and without them, accessing websites and services by domain names would be nearly impossible. In this blog post, we will explore what DNS root servers are, the 13 root servers that underpin the Internet, who manages them, and where they are located.
What is a DNS Root Server?
A DNS root server is a crucial part of the global DNS hierarchy, serving as the starting point for all DNS queries. When a user enters a domain name in a web browser or any application that requires DNS resolution, the request is first sent to a recursive DNS resolver. If the resolver does not have the IP address for the domain in its cache, it contacts one of the DNS root servers to obtain the authoritative name servers for the top-level domains (TLDs) like .com, .org, .net, etc. These TLD name servers, in turn, provide information about the authoritative name servers for the specific domain.
The 13 Root Servers
Contrary to what some may assume, the DNS root servers are not confined to just 13 physical servers. Instead, they are represented by 13 unique IP addresses, denoting the "A" root servers to "M" root servers. These IP addresses are distributed across numerous physical servers worldwide, ensuring redundancy and fault tolerance.
Who Manages the DNS Root Servers?
The DNS root servers are managed by a variety of organizations and entities across the globe, with each lettered root server managed by different entities or organizations. These entities work together under the guidance of the Internet Assigned Numbers Authority (IANA) and the Internet Corporation for Assigned Names and Numbers (ICANN).
Where Are the DNS Root Servers Located?
The DNS root servers are strategically distributed across various geographical locations to ensure global accessibility and minimize latency. Some of the root server instances are hosted by renowned institutions, data centers, universities, and internet service providers (ISPs). The servers are dispersed across multiple continents, including North America, Europe, Asia, and other regions, forming a distributed network that enhances the reliability and resilience of the DNS infrastructure.
Examples of DNS Root Server Instances and Locations:
A Root Server:
Managed by Verisign, Inc.
Located in various data centers worldwide, including Virginia, United States.
C Root Server:
Managed by Cogent Communications, Inc.
Located in multiple locations across the United States, Canada, and Europe.
F Root Server:
Managed by Internet Systems Consortium (ISC).
Located in various data centers across North America, Europe, and Asia.
What happens if a DNS root server becomes unavailable?
The root servers are extremely stable due to the usage of Anycast routing and considerable redundancy. However, a root server may need to modify its IP address on rare instances. In this instance, recursive resolvers can continue to do DNS lookups using the other 12 IP addresses in the root zone until their software is updated with the right addresses for all 13 servers. There is no impact to normal Internet operations when one root server is offline since resolvers will retry until they reach a working root server.
DNS root servers are the backbone of the Internet's addressing system, serving as the starting point for all DNS queries. With 13 unique IP addresses distributed across numerous physical servers worldwide, they enable the efficient resolution of domain names to their corresponding IP addresses. Managed by various organizations and entities under the guidance of ICANN and IANA, these servers are strategically located across the globe, ensuring global accessibility and robustness. The seamless functioning of DNS root servers ensures that users can access websites and services effortlessly, contributing to the continuous growth and connectivity of the Internet as we know it today.
And that's a wrap for this post.
Thank you for reading!
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