Stands For: Address Record
Definition: An A record is a fundamental type of resource record in the Domain Name System (DNS). Its primary function is to map a domain name (or hostname) to its corresponding 32-bit IPv4 address. It is one of the most common record types used on the internet.
Key Characteristics:
- Mapping: Directly associates a hostname (e.g.,
www.example.com) with an IPv4 address (e.g.,93.184.216.34). - Purpose: Enables clients (like web browsers or email clients) to find the correct server on the internet to connect to when a user provides a human-readable domain name.
- Structure: A typical A record includes:
- Name: The hostname the record applies to (e.g.,
www, or@to represent the root domain itself). - TTL (Time to Live): The duration in seconds that the record may be cached by resolvers.
- Class:
IN(for Internet). - Type:
A. - Address: The destination IPv4 address.
- Name: The hostname the record applies to (e.g.,
- Multiple Records: A single hostname can have multiple A records, each pointing to a different IPv4 address. This is a common technique for providing server redundancy and basic client-side load balancing (DNS Round Robin).
Related Records:
- AAAA Record: The equivalent for IPv6, mapping a hostname to a 128-bit IPv6 address.
- CNAME Record (Canonical Name): Maps an alias hostname to another “canonical” hostname. A client resolving the alias must then perform another lookup to find the A or AAAA record of the canonical name.
Usage Note: As of June 2025, the A record remains a core, essential component of DNS. While IPv6 and AAAA records are increasingly important, A records are universally required for devices and services communicating over the IPv4 internet.