BCP 91

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BCPs are stable identifiers for Best Current Practices. A BCP may consist of a single RFC or a group of RFCs related to a specific IETF process or recommended guidelines. The collection may become empty as the BCP evolves.

RFC 3901: BCP 91: DNS IPv6 Transport Operational Guidelines

Best Current Practice

A. Durand
J. Ihren

September 2004
IETF publication
Operations and Management Area

Abstract

This memo provides guidelines and Best Current Practice for operating DNS in a world where queries and responses are carried in a mixed environment of IPv4 and IPv6 networks. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.

Obsoleted by RFC 10001

Abstract

RFC 10001: BCP 91: Operational Guidelines for DNS Transport in Mixed IPv4/IPv6 Environments

Best Current Practice

Momoka
T. Fiebig

August 2026
IETF publication
Operations and Management Area

Abstract

This document provides guidelines and documents best current practice for operating authoritative DNS servers, recursive resolvers, and stub resolvers in a mixed IPv4/IPv6 environment. This document recommends that both authoritative DNS servers and recursive resolvers support IPv4 and IPv6. It also provides guidance on how recursive DNS resolvers should select upstream DNS servers, including when IPv4-embedded IPv6 addresses are available.

This document obsoletes RFC 3901.

Abstract

This document obsoletes RFC 3901.

BCP 91

Subscribe to BCP 91

RFC 3901: BCP 91: DNS IPv6 Transport Operational Guidelines

Abstract

Abstract

RFC 10001: BCP 91: Operational Guidelines for DNS Transport in Mixed IPv4/IPv6 Environments

Abstract

Abstract