Round-robin DNS is a technique of load distribution, load balancing, or fault-tolerance provisioning multiple, redundant Internet Protocol service hosts, e.g., Web server, FTP servers, by managing the Domain Name System's (DNS) responses to address requests from client computers according to an appropriate statistical model.
This behaviour was standardized in RFC 3484 during the definition of IPv6, when applied to IPv4 the bug in Windows Vista and caused issues and defeated round-robin load-balancing.
For example, a company has one domain name and three identical copies of the same web site residing on three servers with three IP addresses.
A round-robin DNS name is, on rare occasions, referred to as a "rotor" due to the rotation among alternative A records.
Round-robin DNS may not be the best choice for load balancing on its own, since it merely alternates the order of the address records each time a name server is queried.