Domain Name System

DNSresource recordDNS recordDNS resolverresolverdomainDNS namedomain namedomain name serverDNS label
The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network.wikipedia
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Domain name

domaindomain namesdomains
It associates various information with domain names assigned to each of the participating entities.
Domain names are formed by the rules and procedures of the Domain Name System (DNS).

Internet

onlinethe Internetweb
The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network.
The overreaching definitions of the two principal name spaces in the Internet, the Internet Protocol address (IP address) space and the Domain Name System (DNS), are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers (ICANN).

List of DNS record types

A recordAPTR record
The most common types of records stored in the DNS database are for Start of Authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME).
This list of DNS record types is an overview of resource records (RRs) permissible in zone files of the Domain Name System (DNS).

Name server

DNS serverdomain name serverauthoritative name server
The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating authoritative name servers for each domain.
An example of a name server is the server component of the Domain Name System (DNS), one of the two principal namespaces of the Internet.

SOA record

SOAStart of Authority
The most common types of records stored in the DNS database are for Start of Authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME).
A Start of Authority record (abbreviated as SOA record) is a type of resource record in the Domain Name System (DNS) containing administrative information about the zone, especially regarding zone transfers.

Reverse DNS lookup

reverse DNSDNS lookuplook up
The most common types of records stored in the DNS database are for Start of Authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME).
In computer networks, a reverse DNS lookup or reverse DNS resolution (rDNS) is the querying technique of the Domain Name System (DNS) to determine the domain name associated with an IP address – the reverse of the usual "forward" DNS lookup of an IP address from a domain name.

CNAME record

CNAMECanonical name recordDNAME
The most common types of records stored in the DNS database are for Start of Authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME).
A Canonical Name record (abbreviated as CNAME record) is a type of resource record in the Domain Name System (DNS) which maps one domain name (an alias) to another (the Canonical Name.)

Zone file

zone data in anything other than flat text fileszonefile
The DNS database is traditionally stored in a structured text file, the zone file, but other database systems are common.
A Domain Name System (DNS) zone file is a text file that describes a DNS zone.

Directory service

directorydirectory servername service
By providing a worldwide, distributed directory service, the Domain Name System has been an essential component of the functionality of the Internet since 1985.

Domain name registry

domain registryregistrydomain name registration
For zones operated by a registry, administrative information is often complemented by the registry's RDAP and WHOIS services.
A domain name registry is a database of all domain names and the associated registrant information in the top level domains of the Domain Name System (DNS) of the Internet that enables third party entities to request administrative control of a domain name.

DNS zone

zonezones
Each subdomain is a zone of administrative autonomy delegated to a manager.
A DNS zone is any distinct, contiguous portion of the domain name space in the Domain Name System (DNS) for which administrative responsibility has been delegated to a single manager.

Hostname

host namehosthostnames
An often-used analogy to explain the Domain Name System is that it serves as the phone book for the Internet by translating human-friendly computer hostnames into IP addresses.
Internet hostnames may have appended the name of a Domain Name System (DNS) domain, separated from the host-specific label by a period ("dot").

Address space

addressaddressableaddressed
The Internet maintains two principal namespaces, the domain name hierarchy and the Internet Protocol (IP) address spaces.
Some nested domain hierarchies appear in the case of directed ordered tree as for the Domain Name System or a directory structure; this is similar to the hierarchical design of postal addresses.

WHOIS

CRISPCross Registry Information Service ProtocolRWhois
For zones operated by a registry, administrative information is often complemented by the registry's RDAP and WHOIS services.
She and the team created domains, with Feinler's suggestion that domains be divided into categories based on the physical address of the computer.

University of Southern California

USCSouthern CaliforniaThe University of Southern California
Maintenance of numerical addresses, called the Assigned Numbers List, was handled by Jon Postel at the University of Southern California's Information Sciences Institute (ISI), whose team worked closely with SRI.
USC was one of the earliest nodes on ARPANET and is the birthplace of the Domain Name System.

InterNIC

Network Information CenterNICInternet Network Information Center
Computers, including their hostnames and addresses, were added to the master file by contacting the SRI's Network Information Center (NIC), directed by Elizabeth Feinler, by telephone during business hours.
The Network Information Center (NIC), also known as InterNIC from 1993 until 1998, was the organization primarily responsible for Domain Name System (DNS) domain name allocations and X.500 directory services.

Hosts (file)

hosts filehosts/etc/hosts
The Stanford Research Institute (now SRI International) maintained a text file named HOSTS.TXT that mapped host names to the numerical addresses of computers on the ARPANET.
The Domain Name System, first described in 1983 and implemented in 1984, automated the publication process and provided instantaneous and dynamic hostname resolution in the rapidly growing network.

Email address

e-mail addressemail addressesEmail Address Internationalization
Users take advantage of this when they use meaningful Uniform Resource Locators (URLs) and e-mail addresses without having to know how the computer actually locates the services.
When delivering email, an SMTP client, e.g., Mail User Agent (MUA), Mail Transfer Agent (MTA), uses the domain name system (DNS) to look up a Resource Record (RR) for the recipient's domain (the part of the email address to the right of the @); if there is a mail exchange Resource Record (MX record) then the returned MX record contains the name of the recipient's mailserver, otherwise the SMTP client uses an address record (A or AAAA).

BIND

Berkeley Internet Name DomainBerkeley Internet Name Domain ServerBIND 9
In 1984, four UC Berkeley students, Douglas Terry, Mark Painter, David Riggle, and Songnian Zhou, wrote the first Unix name server implementation for the Berkeley Internet Name Domain, commonly referred to as BIND.
BIND, or named (pronounced name-dee:, short for name daemon), is the most widely used Domain Name System (DNS) software on the Internet.

Paul Vixie

Mike Karels, Phil Almquist, and Paul Vixie have maintained BIND since then.
Paul Vixie is an American computer scientist whose technical contributions include Domain Name System (DNS) protocol design and procedure, mechanisms to achieve operational robustness of DNS implementations, and significant contributions to open source software principles and methodology.

Paul Mockapetris

Paul V. Mockapetris
Postel directed the task of forging a compromise between five competing proposals of solutions to Paul Mockapetris.
Paul V. Mockapetris (born 1948 in Boston, Massachusetts, US) is an American computer scientist and Internet pioneer, who, together with Jon Postel, invented the Internet Domain Name System (DNS).

Subdomain

sub-domainsubdomainsthird-level domain
Network administrators may delegate authority over sub-domains of their allocated name space to other name servers.
In the Domain Name System (DNS) hierarchy, a subdomain is a domain that is a part of another (main) domain.

DNS root zone

root zoneDNS rootroot domain
The tree sub-divides into zones beginning at the root zone.
The DNS root zone is the top-level DNS zone in the hierarchical namespace of the Domain Name System (DNS) of the Internet.

IP address

IP addressesIPdynamic IP address
The most common types of records stored in the DNS database are for Start of Authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME). Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols.
Anycast methods are useful for global load balancing and are commonly used in distributed DNS systems.

Simple Mail Transfer Protocol

SMTP8BITMIMEemail protocol
The most common types of records stored in the DNS database are for Start of Authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME).
The boundary MTA uses the Domain name system (DNS) to look up the mail exchanger record (MX record) for the recipient's domain (the part of the email address on the right of @).