Root Server
A Root Server is a critical component of the Domain Name System (DNS) hierarchy, serving as the starting point for resolving domain names into IP addresses on the internet. Root servers provide information about Top-Level Domain (TLD) servers, which are essential for the detailed resolution of domain names.
Role of Root Servers
Starting Point for Domain Name Resolution:
The domain name resolution process begins with the root server. It provides the IP addresses of TLD servers.
Guiding to TLD Servers:
Root servers direct queries to the appropriate TLD servers, such as those for ".com", ".org", ".jp", etc., for further resolution of domain names.
How Root Servers Work
Client Request:
When a user attempts to access a website, the browser requests the DNS resolver to resolve the domain name.
Query to Root Server:
The DNS resolver first queries the root server to obtain the IP address of the relevant TLD server.
Query to TLD Server:
Using the information from the root server, the DNS resolver queries the appropriate TLD server to get more specific information about the domain name.
Query to Authoritative DNS Server:
Finally, the DNS resolver queries the authoritative DNS server, which holds the specific IP address for the domain name.
IP Address Retrieval:
The DNS resolver retrieves the IP address corresponding to the domain name and returns it to the browser, allowing the user to access the website.
Management of Root Servers
There are 13 logical root servers globally, each identified by a letter from A to M. These root servers are managed by various organizations and are distributed across multiple physical servers to ensure redundancy and reliability. Some of the managing organizations include:
A Root Server:
VeriSign, Inc.
B Root Server:
Information Sciences Institute (ISI)
C Root Server:
Cogent Communications
D Root Server:
University of Maryland
E Root Server:
NASA Ames Research Center
F Root Server:
Internet Systems Consortium, Inc. (ISC)
I Root Server:
Netnod
J Root Server:
VeriSign, Inc.
K Root Server:
RIPE NCC
L Root Server:
ICANN
M Root Server:
WIDE Project
Summary
Root servers play a crucial role in the DNS system, serving as the starting point for domain name resolution. They provide information about TLD servers, enabling the conversion of domain names into the correct IP addresses. The 13 logical root servers are managed by various organizations and are distributed globally to ensure the reliability and redundancy of the internet infrastructure.