RFC 6844

RFC 6844
Number	6844
Title	Registration of Two New DHCPv6 Options for the Host Identity Protocol
Authors	R. Droms, J. Bound, J. Volz, M. Townsley
Status	Proposed Standard
Published	January 2013
Pages	10
Doi	10.17487/RFC6844

RFC 6844

RFC 6844 specifies two Dynamic Host Configuration Protocol for IPv6 (DHCPv6) options to support the Host Identity Protocol (HIP) and the assignment of Host Identity Tags (HITs). The document defines option formats and operational procedures to convey HIP rendezvous and HIT information to IPv6 hosts during address configuration, enabling interaction with protocols such as Mobile IPv6, SIP, IPsec, and services that rely on cryptographic host identifiers. It was published as a Proposed Standard by the Internet Engineering Task Force (IETF) to register options with the IANA for DHCPv6 use.

Background and Purpose

RFC 6844 addresses the need to distribute HIP-related bootstrap information using DHCPv6, complementing other discovery mechanisms such as the HIP base exchange described in the HIP specifications developed by the IETF HIP WG and research conducted at institutions like the MIT and Stanford University. The registration supports environments where administrative control over host configuration is centralized, as seen in deployments by organizations like ARIN, RIPE NCC, and service providers including AT&T and Verizon. By defining standardized DHCPv6 options, RFC 6844 seeks interoperability among implementations from vendors such as Cisco Systems, Juniper Networks, Microsoft, and Red Hat and aligns with operational models employed in projects like GENI and PlanetLab.

Technical Summary

The document registers two DHCPv6 options: a HIP Rendezvous Option and a HIT Information Option. The HIP Rendezvous Option conveys rendezvous server addresses and parameters used by HIP implementations originating from work tied to the IETF HIP Working Group and academic efforts at Carnegie Mellon University and University of California, Irvine. The HIT Information Option carries Host Identity Tags and related metadata, enabling hosts to present cryptographic identifiers to peers and services such as DNS-based discovery used by BIND or Unbound. RFC 6844 specifies option codes, lengths, and encoding rules consistent with the DHCPv6 option architecture defined by earlier IETF standards like the DHCPv6 base specification and registration procedures used by the IANA.

Message Formats and Procedures

Option formats are byte-oriented and follow the DHCPv6 option layout adopted in specifications from working groups including DHC and NETMOD. The HIP Rendezvous Option includes fields for rendezvous server addresses (IPv6 and optionally IPv4-mapped), port numbers, and transport protocol identifiers consistent with conventions used in RFC 3315 and successors. The HIT Information Option contains one or more HIT entries with length and type fields matching type-length-value patterns familiar from IETF registries such as those maintained by IANA and documents like RFC 7400. Procedures detail how DHCPv6 servers encode options and how DHCPv6 clients process received options, describing interactions with local HIP implementations from projects like OpenHIP and GNU Hurd derivatives that implement HIP stacks.

Interoperability and Deployment Considerations

RFC 6844 emphasizes backward compatibility with DHCPv6 servers and clients that ignore unknown options, as required by the DHCP specifications overseen by the IETF DHC Working Group. Interoperability testing considerations cite vendor ecosystems represented by Cisco Systems, Juniper Networks, Ericsson, and open-source platforms such as Linux distributions (e.g., Debian, Ubuntu) and FreeBSD. Deployment scenarios include enterprise networks managed via tools from Ansible, Puppet, and Chef and service-provider contexts operated by organizations like NTT and Deutsche Telekom. The specification anticipates mixed-mode environments where HIP-aware applications such as OpenSSH and OpenVPN coexist with traditional IP-based services, recommending graceful handling of option presence or absence.

Security and Privacy Considerations

Security guidance in RFC 6844 reflects principles from IETF security documents and the HIP architecture, noting the sensitivity of HITs and rendezvous server addresses. The document recommends integrity and confidentiality protections for DHCPv6 exchanges using mechanisms such as DHCP authentication options and transport-layer security approaches analogous to IPsec and TLS deployments seen in infrastructures of Google, Facebook, and financial institutions like SWIFT. Privacy considerations reference potential tracking risks similar to debates around persistent identifiers in protocols used by services like Skype and WhatsApp, advising minimal exposure of HITs and the use of short-lived or privacy-preserving identifiers where possible.

Implementation and Operational Experience

Implementers such as vendors and open-source projects reported on prototype integrations of the registered options in DHCPv6 servers (for example, modules for isc-dhcp and Kea DHCP) and client stacks in HIP implementations like OpenHIP and experimental stacks developed at EPFL and KTH Royal Institute of Technology. Operational experience highlighted the importance of administrative policies in registries operated by IANA and regional registries (ARIN, RIPE NCC) and the role of community testing in environments such as IETF, hackathons and interoperability events like IETF Interop. Deployments underscored practical issues: coordination with DNS infrastructure (e.g., BIND), integration with network management systems from Nagios and Zabbix, and the need for clear guidance in vendor documentation from companies like Cisco Systems and Juniper Networks.

Category:Internet standards