This memo describes errors often found in both the operation of Domain Name System (DNS) servers, and in the data that these DNS servers contain. This memo tries to summarize current Internet requirements as well as common practice in the operation and configuration of the DNS. This memo also tries to summarize or expand upon issues raised in [RFC 1537].
http://www.ietf.org/rfc/rfc1912.txt
Vegeu Servidor_DNS#Cache