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Preference for IPv6 ULAs over IPv4 addresses in RFC6724

Document Type Replaced Internet-Draft (6man WG)
Expired & archived
Authors Nick Buraglio , Tim Chown , Jeremy Duncan
Last updated 2023-09-26 (Latest revision 2023-08-17)
Replaced by draft-ietf-6man-rfc6724-update
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Additional resources Mailing list discussion
Stream WG state Adopted by a WG
Document shepherd (None)
IESG IESG state Replaced by draft-ietf-6man-rfc6724-update
Consensus boilerplate Unknown
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


This document updates RFC 6724 based on operational experience gained since its publication over ten years ago. In particular it updates the preference of Unique Local Addresses (ULAs) in the default address selection policy table, which as originally defined by RFC 6724 has lower precedence than legacy IPv4 addressing. The update places both IPv6 Global Unicast Addresses (GUAs) and ULAs ahead of all IPv4 addresses on the policy table to better suit operational deployment and management of ULAs in production. In updating the RFC 6724 default policy table, this document also demotes the preference for 6to4 addresses. These changes to default behavior improve supportability of common use cases such as, but not limited to, automatic / unmanaged scenarios. It is recognized that some less common deployment scenarios may require explicit configuration or custom changes to achieve desired operational parameters.


Nick Buraglio
Tim Chown
Jeremy Duncan

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)