What is a Nameserver?

A nameserver is a server on a network that translates human-readable domain names into machine-readable IP addresses. This process allows users to access websites and other resources on the internet using easy-to-remember names instead of numerical addresses. Nameservers play a role in how the internet operates, ensuring that when you type a website address into your browser, you are directed to the correct webpage.

Dissecting Nameservers

The concept of a nameserver, fundamental to networked computing, became formally recognized with the development of the Domain Name System (DNS) in 1983. Introduced by Paul Mockapetris through the publication of RFCs 882 and 883, and later refined in 1987 by RFCs 1034 and 1035, DNS and nameservers were designed to resolve human-readable domain names (like www.example.com) into machine-readable IP addresses (such as 192.0.2.1). 

This innovation marked a pivotal moment in making internet resources accessible without the need to memorize complex numerical addresses, aiming for a distributed, scalable system to streamline the process of domain name resolution.

How a Nameserver works

The operation of a nameserver involves a series of steps that occur when a user attempts to access a website or other online resource using a domain name. 

1. User Query: The process begins when a user enters a domain name (e.g., www.example.com) into a web browser or other internet-enabled application.
2. DNS Query Initiation: The user's device sends a DNS query to a recursive nameserver. This recursive nameserver is typically provided by the user's Internet Service Provider (ISP) or configured manually in the network settings.
3. Recursive Resolution: The recursive nameserver begins the resolution process by checking its cache to see if it has recently resolved the domain name to an IP address. If the information is not in the cache or has expired, the recursive nameserver proceeds to query authoritative nameservers to resolve the domain name.
4. Root Nameserver Query: If the recursive nameserver does not have the IP address in its cache, it starts by querying one of the 13 root nameservers. These root nameservers maintain information about the top-level domain (TLD) nameservers responsible for the different domain extensions (e.g., .com, .org, .net).
5. TLD Nameserver Query: The root nameserver responds to the recursive nameserver with the IP addresses of the TLD nameservers responsible for the specific top-level domain of the requested domain name (e.g., the .com TLD nameservers for www.example.com).
6. Authoritative Nameserver Query: The recursive nameserver sends a query to one of the TLD nameservers to obtain the IP addresses of the authoritative nameservers for the requested domain (e.g., the nameservers provided by the domain registrar for example.com).
7. Resolution by Authoritative Nameserver: The TLD nameserver responds with the IP addresses of the authoritative nameservers for the domain. The recursive nameserver then queries one of these authoritative nameservers directly.
8. IP Address Resolution: The authoritative nameserver provides the IP address associated with the requested domain name to the recursive nameserver.
9. Response to User: The recursive nameserver caches the IP address and returns it to the user's device, allowing the user's device to establish a connection to the desired website or online resource.
10. Caching and TTL: The recursive nameserver caches the IP address and associated information for a specified time, known as the Time-to-Live (TTL). This caching improves performance by reducing the need for repeated queries for frequently accessed domain names.

Types of Nameserver

In the Domain Name System (DNS), there are primarily three types of nameservers based on their roles and responsibilities:

• Authoritative Nameservers: Authoritative nameservers are responsible for providing authoritative DNS information for specific domain names. These servers hold the original and definitive DNS records for the domain names they are authoritative for. When queried for information about a domain name, authoritative nameservers respond with the IP addresses associated with that domain. Authoritative nameservers are further categorized as primary (master) and secondary (slave) nameservers.
• Primary (Master) Nameservers: The primary nameserver is the authoritative nameserver that holds the original copy of the DNS zone file for a domain. It is responsible for managing and making updates to the DNS records for the domain. Changes to the DNS records, such as adding or modifying resource records, are made on the primary nameserver first.
• Secondary (Slave) Nameservers: Secondary nameservers maintain a copy of the DNS zone file for a domain, which is synchronized with the primary nameserver. These nameservers periodically query the primary nameserver for updates to the zone file and replicate the changes. Secondary nameservers provide redundancy and fault tolerance, ensuring that DNS resolution is still available even if the primary nameserver is unavailable.
• Recursive Nameservers: Recursive nameservers, also known as caching nameservers or resolver nameservers, handle DNS queries on behalf of clients (such as web browsers or applications). When a client sends a DNS query to a recursive nameserver, the recursive nameserver performs the necessary steps to resolve the domain name to an IP address. If the recursive nameserver does not have the requested information cached, it recursively queries other nameservers until it obtains the authoritative information for the domain. Recursive nameservers cache the results of DNS queries to improve performance and reduce network traffic.
• Root Nameservers: Root nameservers are the highest level of nameservers in the DNS hierarchy. They are responsible for providing information about the authoritative nameservers for the top-level domains (TLDs), such as .com, .org, .net, etc. When a recursive nameserver receives a DNS query for a domain, it starts by querying one of the root nameservers to determine the authoritative nameservers for the appropriate TLD. There are 13 sets of root nameservers distributed globally, managed by different organizations.