A record

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A record

A record in computer science is a structured data set that contains information about a particular entity. Each record consists of a collection of fields, each containing a specific value associated with the entity.

What does A record mean?

An A record is a type of resource record in the Domain [Name](https://amazingalgorithms.com/definitions/name) System (DNS) used to map a Domain Name to an Internet Protocol (IP) address. It is one of the most basic and essential DNS records, and is used to resolve domain names to IP addresses so that computers can communicate with each other on the Internet.

A records contain a single IP address, which is either an IPv4 address or an IPv6 address. When a computer tries to resolve a domain name, it sends a query to a DNS server. The DNS server will then look up the A record for the domain name and return the corresponding IP address. The computer can then use the IP address to connect to the server that hosts the Website or other service associated with the domain name.

A records are essential for the proper functioning of the Internet. Without A records, computers would not be able to resolve domain names to IP addresses, and would not be able to communicate with each other on the Internet.

Applications

A records are used in a variety of applications, including:

  • Website hosting: A records are used to map domain names to the IP addresses of web servers. This allows users to access websites by typing the domain name into their web browser.
  • Email: A records are used to map domain names to the IP addresses of mail servers. This allows users to send and receive email using domain names.
  • File sharing: A records are used to map domain names to the IP addresses of file servers. This allows users to share files with each other over the Internet.
  • Virtual private networks (VPNs): A records are used to map domain names to the IP addresses of VPN gateways. This allows users to connect to VPNs and securely access private networks over the Internet.

History

The A record was first defined in RFC 1035, which was published in November 1987. A records have been used since the early days of the Internet, and are still one of the most important DNS records in use today.

The A record has been updated several times over the years. In 1994, RFC 1637 was published, which added support for IPv6 addresses in A records. In 2000, RFC 2874 was published, which added support for multiple A records for a single domain name.

A records are an essential part of the Domain Name System and are used in a variety of applications. They are a critical component of the Internet and help to ensure that computers can communicate with each other efficiently.