20240623

My circadian rhythm is broken and *vomiting sound*

DNS server types

[1] DNS server types | Cloudflare

All DNS servers fall into one of four categories: Recursive resolvers, root nameservers, TLD nameservers, and authoritative nameservers.

DNS Recursive resolver (also known as recursive DNS resolver or recursive DNS server)

[2] IBM: What Is a DNS server?

…this is the first stop for a recursive query—the process of one DNS server communicating with other DNS servers to locate and return an IP address.

This server receives a DNS query and can connect a user to the desired site using cached data, or if site data is not cached, send a follow-up request to DNS name servers.

Most DNS recursors are provided by internet service providers (ISP).

[3] Verizon: What is an Internet Service Provider (ISP)?

An internet service provider (ISP) is a company that provides access to the internet.

DNS root name server

When a recursive DNS server does not have cached data, it sends a DNS query to the DNS root name server. The root name server accepts the query and forwards it to a top level domain (TLD) name server[2].

Which TLD server the query is forwarded to depends on the desired sites extension: .com, .org or .net, for example. There are 13 main DNS root servers operated by the Internet Corporation for Assigned Names and Numbers (ICANN)[2].

The 13 DNS root nameservers are known to every recursive resolver, and they are the first stop in a recursive resolver’s quest for DNS records. A root server accepts a recursive resolver’s query which includes a domain name, and the root nameserver responds by directing the recursive resolver to a TLD nameserver, based on the extension of that domain (.com, .net, .org, etc.). The root nameservers are overseen by a nonprofit called the Internet Corporation for Assigned Names and Numbers (ICANN)[1].

Top level domain (TLD) name server

TLD name servers contain data related to domain names with the same extension. This means there are designated TLD servers for websites with the extensions .com, .org and .net. Once the query reaches the correct TLD name server, it is then directed to the authoritative name server[2].

Management of TLD nameservers is handled by the Internet Assigned Numbers Authority (IANA), which is a branch of ICANN. The IANA breaks up the TLD servers into two main groups:[1]

Authoritative name server

Generally the final step in the process of retrieving an IP address, authoritative DNS servers store information related to specific domain names in DNS resource records. These DNS records contain information about a specific domain and its corresponding IP address. When the correct IP address is found, it is sent back to the recursive resolver. If it is not located, the user will receive an error message[2].

ClouDNS: What Is Authoritative DNS server?

The authoritative DNS servers can be where the website is hosted or where the DNS provider is.

I use Cloudflare to manage DNS records of my domain. Here, Cloudflare serves as the authoritative DNS server for my domain.

Summary

  1. User’s device → Recursive DNS server
  2. Recursive DNS server → Root name server (root server responds with TLD server information)
  3. Recursive DNS server → TLD server (TLD server responds with authoritative server information)
  4. Recursive DNS server → Authoritative server (authoritative server responds with the domain’s IP address)
  5. Recursive DNS server → User’s device

Root servers and TLD servers don’t cache DNS records; Recursive Resolvers do.

Our current internet infrastructure consists of so many components that I’m surprised the internet continues to work without major incidents.


Total 3000 kcal :cry: but I don't feel well, so it may be justifiable.


TODO:


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