Internet Engineering Task Force (IETF) T. Mrugalski Request for Comments: 8415 M. Siodelski Obsoletes: 3315, 3633, 3736, 4242, 7083, ISC 7283, 7550 B. Volz Category: Standards Track A. Yourtchenko ISSN: 2070-1721 Cisco M. Richardson SSW S. Jiang Huawei T. Lemon Nibbhaya Consulting T. Winters UNH-IOL November 2018Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
Abstract This document describes the Dynamic Host Configuration Protocol for IPv6 (DHCPv6): an extensible mechanism for configuring nodes with network configuration parameters, IP addresses, and prefixes. Parameters can be provided statelessly, or in combination with stateful assignment of one or more IPv6 addresses and/or IPv6 prefixes. DHCPv6 can operate either in place of or in addition to stateless address autoconfiguration (SLAAC). This document updates the text from RFC 3315 (the original DHCPv6 specification) and incorporates prefix delegation (RFC 3633), stateless DHCPv6 (RFC 3736), an option to specify an upper bound for how long a client should wait before refreshing information (RFC 4242), a mechanism for throttling DHCPv6 clients when DHCPv6 service is not available (RFC 7083), and relay agent handling of unknown messages (RFC 7283). In addition, this document clarifies the interactions between models of operation (RFC 7550). As such, this document obsoletes RFC 3315, RFC 3633, RFC 3736, RFC 4242, RFC 7083, RFC 7283, and RFC 7550. Mrugalski, et al. Standards Track [Page 1]
RFC 8415 DHCP for IPv6 November 2018 Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8415. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Mrugalski, et al. Standards Track [Page 2]
RFC 8415 DHCP for IPv6 November 2018 Table of Contents 1. Introduction ....................................................6 1.1. Relationship to Previous DHCPv6 Standards ..................7 1.2. Relationship to DHCPv4 .....................................8 2. Requirements ....................................................8 3. Background ......................................................8 4. Terminology .....................................................9 4.1. IPv6 Terminology ...........................................9 4.2. DHCP Terminology ..........................................11 5. Client/Server Exchanges ........................................16 5.1. Client/Server Exchanges Involving Two Messages ............16 5.2. Client/Server Exchanges Involving Four Messages ...........17 5.3. Server/Client Exchanges ...................................18 6. Operational Models .............................................18 6.1. Stateless DHCP ............................................18 6.2. DHCP for Non-temporary Address Assignment .................19 6.3. DHCP for Prefix Delegation ................................19 6.4. DHCP for Customer Edge Routers ............................22 6.5. DHCP for Temporary Addresses ..............................22 6.6. Multiple Addresses and Prefixes ...........................22 7. DHCP Constants .................................................23 7.1. Multicast Addresses .......................................23 7.2. UDP Ports .................................................24 7.3. DHCP Message Types ........................................24 7.4. DHCP Option Codes .........................................26 7.5. Status Codes ..............................................26 7.6. Transmission and Retransmission Parameters ................27 7.7. Representation of Time Values and "Infinity" as a Time Value ................................................28 8. Client/Server Message Formats ..................................29 9. Relay Agent/Server Message Formats .............................30 9.1. Relay-forward Message .....................................31 9.2. Relay-reply Message .......................................31 10. Representation and Use of Domain Names ........................32 11. DHCP Unique Identifier (DUID) .................................32 11.1. DUID Contents ............................................33 11.2. DUID Based on Link-Layer Address Plus Time (DUID-LLT) ....33 11.3. DUID Assigned by Vendor Based on Enterprise Number (DUID-EN) .........................................35 11.4. DUID Based on Link-Layer Address (DUID-LL) ...............36 11.5. DUID Based on Universally Unique Identifier (DUID-UUID) ..37 12. Identity Association ..........................................37 12.1. Identity Associations for Address Assignment .............38 12.2. Identity Associations for Prefix Delegation ..............38 Mrugalski, et al. Standards Track [Page 3]
RFC 8415 DHCP for IPv6 November 2018 13. Assignment to an IA ...........................................39 13.1. Selecting Addresses for Assignment to an IA_NA ...........39 13.2. Assignment of Temporary Addresses ........................40 13.3. Assignment of Prefixes for IA_PD .........................41 14. Transmission of Messages by a Client ..........................41 14.1. Rate Limiting ............................................41 14.2. Client Behavior when T1 and/or T2 Are 0 ..................42 15. Reliability of Client-Initiated Message Exchanges .............43 16. Message Validation ............................................45 16.1. Use of Transaction IDs ...................................45 16.2. Solicit Message ..........................................46 16.3. Advertise Message ........................................46 16.4. Request Message ..........................................46 16.5. Confirm Message ..........................................47 16.6. Renew Message ............................................47 16.7. Rebind Message ...........................................47 16.8. Decline Message ..........................................47 16.9. Release Message ..........................................48 16.10. Reply Message ...........................................48 16.11. Reconfigure Message .....................................48 16.12. Information-request Message .............................49 16.13. Relay-forward Message ...................................49 16.14. Relay-reply Message .....................................49 17. Client Source Address and Interface Selection .................49 17.1. Source Address and Interface Selection for Address Assignment .......................................49 17.2. Source Address and Interface Selection for Prefix Delegation ...............................................50 18. DHCP Configuration Exchanges ..................................50 18.1. A Single Exchange for Multiple IA Options ................53 18.2. Client Behavior ..........................................53 18.2.1. Creation and Transmission of Solicit Messages .....55 18.2.2. Creation and Transmission of Request Messages .....57 18.2.3. Creation and Transmission of Confirm Messages .....59 18.2.4. Creation and Transmission of Renew Messages .......60 18.2.5. Creation and Transmission of Rebind Messages ......62 18.2.6. Creation and Transmission of Information-request Messages ......................63 18.2.7. Creation and Transmission of Release Messages .....64 18.2.8. Creation and Transmission of Decline Messages .....65 18.2.9. Receipt of Advertise Messages .....................67 18.2.10. Receipt of Reply Messages ........................68 18.2.10.1. Reply for Solicit (with Rapid Commit), Request, Renew, or Rebind ......69 18.2.10.2. Reply for Release and Decline ...........72 18.2.10.3. Reply for Confirm .......................72 18.2.10.4. Reply for Information-request ...........72 Mrugalski, et al. Standards Track [Page 4]
RFC 8415 DHCP for IPv6 November 2018 18.2.11. Receipt of Reconfigure Messages ..................72 18.2.12. Refreshing Configuration Information .............73 18.3. Server Behavior ..........................................74 18.3.1. Receipt of Solicit Messages .......................75 18.3.2. Receipt of Request Messages .......................77 18.3.3. Receipt of Confirm Messages .......................79 18.3.4. Receipt of Renew Messages .........................79 18.3.5. Receipt of Rebind Messages ........................81 18.3.6. Receipt of Information-request Messages ...........83 18.3.7. Receipt of Release Messages .......................84 18.3.8. Receipt of Decline Messages .......................85 18.3.9. Creation of Advertise Messages ....................85 18.3.10. Transmission of Advertise and Reply Messages .....87 18.3.11. Creation and Transmission of Reconfigure Messages .........................................87 18.4. Reception of Unicast Messages ............................