DNS, or Domain Name System, is like a phone book for the internet. Just like a phone book maps people's names to their phone numbers, DNS maps website names to their corresponding IP addresses.

When you type a website name like "hijackalert.com" into your web browser, your computer sends a request to a DNS server to look up the IP address associated with that domain name. Once the IP address is found, your computer can then connect to the website's server and download the web page.

The DNS was invented by computer scientist and internet pioneer Paul V. Mockapetris in 1983.

A DNS name server is a computer that helps your device find the website you are trying to connect to on the Internet. There are several types of DNS servers, including:

Root DNS server: These servers are responsible for maintaining the root zone of the DNS hierarchy. They are the starting point for all DNS queries and contain information about top-level domains, such as .com, .org, and .net.

TLD DNS server: The TLD (Top-Level Domain) DNS server is responsible for storing and providing DNS records for a specific top-level domain, such as .com or .net.

Authoritative DNS server: This type of server is responsible for storing and providing DNS records for a specific domain name. Authoritative name servers contain the official records for a domain, such as IP addresses, and respond to DNS queries with information about the domain they are authoritative for.

Recursive DNS server: This type of server is responsible for fetching DNS records from other name servers on behalf of clients or end-users. When a user types in a domain name, a recursive DNS server will recursively search for the correct IP address by querying other DNS servers until it finds the correct one in the folowing succession: root server, TLD server and finally authorative server.

A DNS provider is a service that helps translate human-friendly website names (like www.example.com) into computer-friendly IP addresses (like 123.45.67.89) that computers use to connect to the website.

When you type a website name into your browser, your computer sends a request to a DNS server to find out the corresponding IP address for that website. The DNS server looks up the information in its database and sends back the IP address to your computer, which can then connect to the website.

A DNS provider is a company that operates one or more DNS servers and provides access to those servers for other people and companies to use. They often offer additional services like security, speed optimizations, and analytics to help website owners manage their online presence.

A DNS record is a piece of information that is stored in a DNS database and provides instructions to the DNS server on how to handle requests for a particular domain or subdomain.

A (Address) Maps a domain name to an IPv4 address.

AAAA (IPv6 Address) Maps a domain name to an IPv6 address.

CAA (Certificate Authority Authorization) Specifies which certificate authorities (CAs) are authorized to issue SSL/TLS certificates for a domain.

CNAME (Canonical Name) Maps an alias name to the canonical name for a host.

GID (Group Identifier) Used in the X.500 directory system to map a group name to its corresponding GID.

HINFO (Host Information) Providing Minimal-Sized Responses to DNS Queries That Have QTYPE=ANY

NS (Name Server) Specifies the authoritative name servers for a domain.

MB (Mailbox) [Obsolete] Used to specify the primary mailbox for a host, but is now obsolete and has been replaced by the MX record.

MD (Mail Destination) [Obsolete] Used to specify the mail exchange for a host, but is now obsolete and has been replaced by the MX record.

MG (Mail Group) [Obsolete] Used to specify a mail group, but is now obsolete and has been replaced by the MX record.

MF MF (Mail Forwarder) [Obsolete] Used to specify a mail forwarder, but is now obsolete and has been replaced by the MX record.

MINFO (Mailbox Information) [Obsolete] Used to specify mailbox-related information for a host, but is now obsolete.

MX (Mail Exchange) Maps a domain name to a list of mail exchange servers for that domain.

NAPTR (Naming Authority Pointer) Specifies regular expression based rewriting rules for domain names.

NULL [Obsolete] A record that contains no data.

PTR (Pointer) This type of DNS record is used in reverse DNS lookups to map an IP address to a domain name.

SOA (Start of Authority) Specifies authoritative information about the DNS zone, including the primary name server, email contact, and serial number and several timers relating to refreshing the zone.

SPF (Sender Policy Framework) [Obsolete] Used as part of the Sender Policy Framework protocol as an alternative to storing SPF data in TXT records, using the same format.

SRV (Service) Specifies the location of services for a domain, such as SIP or LDAP.

TXT (Text) Provides arbitrary text data in the DNS record.

UID (User ID) [Obsolete] Used in the X.500 directory system to map a user's name to its corresponding UID.

UINFO (User Information) [Obsolete] Used to provide information about a user, but is now obsolete and has been replaced by the TXT record.

UNSPEC (Unspecified) [Obsolete] Used for experimental purposes, but is now obsolete and has no current use.

URI URI (Uniform Resource Identifier) Can be used for publishing mappings from hostnames to URIs.

WKS (Well-Known Services) [OBSOLETE] Used to describe the well-known services that a host supports, including the protocol, port number, and any associated services.

Please note that the above list contains the most commmon record types and is thus incomplete. You can read more about the current and all other obsolete domain record types on Wikipedia.

The DNS root zone can be thought of as the "starting point" for the internet's domain name system. It is the highest level in the domain name hierarchy and contains information about the top-level domains (TLDs) such as ".com", ".org", ".net", and so on.

The root zone file contains a list of all the TLDs and their associated domain name servers. When the DNS resolver receives a request for a domain name, it checks the root zone file to determine which TLD the domain name belongs to, and then contacts the appropriate TLD's domain name servers to determine the authorative nameservers for that domain.

IANA, or the Internet Assigned Numbers Authority (currently a function of ICANN) is a non-profit organization responsible for coordinating certain key elements of the internet, such as domain names, IP addresses, and protocol parameters.

Specifically, IANA manages the global allocation of IP addresses and domain names, and it assigns unique protocol parameters for internet standards. This helps ensure that devices connected to the internet can communicate with each other effectively and without conflicts.

ICANN, or the Internet Corporation for Assigned Names and Numbers, is a non-profit organization responsible for managing the domain name system (DNS) of the internet.

ICANN oversees the assignment of domain names and the allocation of IP addresses to ensure that each website on the internet has a unique and identifiable address. It also coordinates the operation and maintenance of the DNS root zone, which is the top-level of the DNS hierarchy.

In addition, ICANN works to establish policies for how domain names are managed and to ensure that the DNS is secure, stable, and accessible to everyone. It also accredits and regulates domain name registrars, which are companies that sell domain names to the public.

TLDs, or Top-Level Domains, are the highest level in the hierarchical domain name system of the internet. They are the part of a domain name that comes after the final dot, such as ".com", ".org", ".net", and so on.

TLDs are managed by the Internet Assigned Numbers Authority (IANA), which is responsible for coordinating and overseeing the global internet's domain name system. TLDs can be divided into two main categories: generic top-level domains (gTLDs) and country-code top-level domains (ccTLDs).

Some common gTLDs include ".com" (for commercial organizations), ".org" (for non-profit organizations), ".net" (for network infrastructure), and ".edu" (for educational institutions). Some common ccTLDs include ".uk" (for the United Kingdom), ".ca" (for Canada), and ".jp" (for Japan).