What Is DNS Server and Its Types?
A DNS server, short for Domain Name System server, is a crucial component of the Internet infrastructure that helps translate human-readable domain names into machine-readable IP addresses. It acts as a phonebook for the Internet, allowing users to access websites and other online resources by simply typing in a domain name instead of having to remember the associated IP address.
Types of DNS Servers
There are several types of DNS servers that perform different functions within the Domain Name System. Let’s explore some of the most common types:
1. Recursive DNS Servers
A recursive DNS server, also known as a resolver, is responsible for handling client requests and providing them with the requested information. When you enter a domain name in your web browser, your computer sends a query to a recursive DNS server to resolve the domain name into an IP address.
The recursive DNS server then recursively queries other authoritative DNS servers until it obtains the final answer. It caches this information to improve future query response times and reduce network traffic.
2. Authoritative DNS Servers
Authoritative DNS servers store specific domain name information and provide authoritative answers when queried about those domains. They are responsible for maintaining and distributing accurate records for specific domains or zones.
If a recursive DNS server receives a query for which it doesn’t have cached information, it will contact an authoritative DNS server responsible for that domain to obtain the necessary information.
3. Top-Level Domain (TLD) Name Servers
TLD name servers are responsible for storing information about top-level domains such as .com, .org, .net, etc. They maintain records of the authoritative DNS servers responsible for each domain within their respective TLD.
When a recursive DNS server receives a query for a domain under a specific TLD, it contacts the corresponding TLD name server to obtain the authoritative DNS server information for that domain.
4. Root Name Servers
Root name servers are the foundation of the DNS hierarchy. There are 13 sets of root name servers distributed worldwide, identified by letters A to M. These servers store the information about the top-level domains and their respective TLD name servers.
When a recursive DNS server doesn’t have any cached information and needs to resolve a domain, it starts by querying one of these root name servers. The root name server then directs the recursive DNS server to the appropriate TLD name server based on the requested domain’s TLD.
In summary, DNS servers play a vital role in translating human-readable domain names into machine-readable IP addresses. Recursive DNS servers handle client queries and fetch information from authoritative DNS servers, which store specific domain information. Additionally, TLD name servers maintain records for top-level domains, while root name servers form the backbone of the entire DNS system.
Understanding how DNS servers work is crucial for anyone involved in managing or troubleshooting network issues, as it allows them to comprehend the process behind website accessibility and efficient routing on the Internet.