Dynamic Host Configuration Protocol (DHCP): IPv4 and IPv6 Dual-Stack Issues
RFC 4477
Document | Type | RFC - Informational (May 2006; No errata) | |
---|---|---|---|
Authors | Christian Strauf , Stig Venaas , Tim Chown | ||
Last updated | 2015-10-14 | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4477 (Informational) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Margaret Cullen | ||
Send notices to | rdroms@cisco.com |
Network Working Group T. Chown Request for Comments: 4477 University of Southampton Category: Informational S. Venaas UNINETT C. Strauf Clausthal University of Technology May 2006 Dynamic Host Configuration Protocol (DHCP): IPv4 and IPv6 Dual-Stack Issues Status of This Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2006). Abstract A node may have support for communications using IPv4 and/or IPv6 protocols. Such a node may wish to obtain IPv4 and/or IPv6 configuration settings via the Dynamic Host Configuration Protocol (DHCP). The original version of DHCP (RFC 2131) designed for IPv4 has now been complemented by a new DHCPv6 (RFC 3315) for IPv6. This document describes issues identified with dual IP version DHCP interactions, the most important aspect of which is how to handle potential problems in clients processing configuration information received from both DHCPv4 and DHCPv6 servers. The document makes a recommendation on the general strategy on how best to handle such issues and identifies future work to be undertaken. Chown, et al. Informational [Page 1] RFC 4477 DHCP: Dual-Stack Issues May 2006 Table of Contents 1. Introduction ....................................................3 2. Configuration Scenarios .........................................3 3. Dual-Stack Issues ...............................................4 3.1. Handling Multiple Responses ................................4 3.2. Different Administrative Management ........................5 3.3. Multiple Interfaces ........................................5 3.4. DNS Load Balancing .........................................5 3.5. DNS Search Path Issues .....................................5 3.6. Protocol Startup Sequence ..................................6 3.7. DHCP Option Variations .....................................6 3.8. Security Issues ............................................6 4. Potential Solutions .............................................7 4.1. Separate DHCP Servers ......................................7 4.2. Single DHCPv6 Server .......................................8 4.3. Optimising for Failure with Lists of Addresses .............9 4.4. Administrative and Other Areas ............................10 5. Summary ........................................................10 6. Security Considerations ........................................12 7. Acknowledgements ...............................................12 8. Informative References .........................................12 Chown, et al. Informational [Page 2] RFC 4477 DHCP: Dual-Stack Issues May 2006 1. Introduction The original specification of the Dynamic Host Configuration Protocol (DHCP) was made with only IPv4 in mind. That specification has been subsequently revised, up to the latest version of DHCP [1]. With the arrival of IPv6, a new DHCP specification for IPv6 has been designed and published as DHCPv6 [4]. These protocols allow nodes to communicate via IPv4 or IPv6 (respectively) to retrieve configuration settings for operation in a managed environment. While an IPv6 node may acquire address-related configuration settings via IPv6 stateless address autoconfiguration [2], such a node may wish to use stateless DHCPv6 [5] for other administratively configured options, such as DNS or NTP. In early IPv6 deployments, a dual-stack mode of operation is typically used. There will thus be nodes that require both IPv4 and IPv6 configuration settings. This document discusses issues with obtaining such settings in a dual-stack environment. There is a general multihoming issue to be solved for DHCP. A host might simultaneously be connected to multiple networks managed by multiple parties. Also, IPv4 and IPv6 might be managed by separate parties. While these issues are touched on in this document, here we focus on the specific issues for operating DHCP in a mixed (typically dual-stack) IPv4 and IPv6 environment within a single administrative domain. In this document, we refer to a "DHCP server" as a server implementing the original DHCP [1], and a "DHCPv6 server" as a serverShow full document text