ISC-DHCP-REFERENCES: ISC DHCP References Collection
Description: ISC DHCP References Collection
Keywords: ISC, DHCP, Reference Implementation

TOC

ISC-DHCP-REFERENCES | D. Hankins
| T. Mrugalski
| ISC
| January 04, 2012

#
ISC DHCP References Collection

### Abstract

This document describes a collection of reference material to which ISC DHCP has been implemented as well as a more complete listing of references for DHCP and DHCPv6 protocols.

### Copyright Notice

Copyright (c) 2006-2007,2009,2011 by Internet Systems Consortium, Inc. ("ISC")

Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

### Table of Contents

TOC

### 1. Introduction

As a little historical anecdote, ISC DHCP once packaged all the relevant RFCs and standards documents along with the software package. Until one day when a voice was heard from one of the many fine institutions that build and distribute this software... they took issue with the IETF's copyright on the RFC's. It seems the IETF's copyrights don't allow modification of RFC's (except for translation purposes).

Our main purpose in providing the RFCs is to aid in documentation, but since RFCs are now available widely from many points of distribution on the Internet, there is no real need to provide the documents themselves. So, this document has been created in their stead, to list the various IETF RFCs one might want to read, and to comment on how well (or poorly) we have managed to implement them.

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### 2. Definition: Reference Implementation

ISC DHCP, much like its other cousins in ISC software, is self-described as a 'Reference Implementation.' There has been a great deal of confusion about this term. Some people seem to think that this term applies to any software that once passed a piece of reference material on its way to market (but may do quite a lot of things that aren't described in any reference, or may choose to ignore the reference it saw entirely). Other folks get confused by the word 'reference' and understand that to mean that there is some special status applied to the software - that the software itself is the reference by which all other software is measured. Something along the lines of being "The DHCP Protocol's Reference Clock," it is supposed.

The truth is actually quite a lot simpler. Reference implementations are software packages which were written to behave precisely as appears in reference material. They are written "to match reference."

If the software has a behaviour that manifests itself externally (whether it be something as simple as the 'wire format' or something higher level, such as a complicated behaviour that arises from multiple message exchanges), that behaviour must be found in a reference document.

Anything else is a bug, the only question is whether the bug is in reference or software (failing to implement the reference).

This means:

- To produce new externally-visible behaviour, one must first provide a reference.
- Before changing externally visible behaviour to work around simple incompatibilities in any other implementation, one must first provide a reference.

That is the lofty goal, at any rate. It's well understood that, especially because the ISC DHCP Software package has not always been held to this standard (but not entirely due to it), there are many non-referenced behaviours within ISC DHCP.

The primary goal of reference implementation is to prove the reference material. If the reference material is good, then you should be able to sit down and write a program that implements the reference, to the word, and come to an implementation that is distinguishable from others in the details, but not in the facts of operating the protocol. This means that there is no need for 'special knowledge' to work around arcane problems that were left undocumented. No secret handshakes need to be learned to be imparted with the necessary "real documentation".

Also, by accepting only reference as the guidebook for ISC DHCP's software implementation, anyone who can make an impact on the color texture or form of that reference has a (somewhat indirect) voice in ISC DHCP's software design. As the IETF RFC's have been selected as the source of reference, that means everyone on the Internet with the will to participate has a say.

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### 3. Low Layer References

It may surprise you to realize that ISC DHCP implements 802.1 'Ethernet' framing, Token Ring, and FDDI. In order to bridge the gap there between these physical and DHCP layers, it must also implement IP and UDP framing.

The reason for this stems from Unix systems' handling of BSD sockets (the general way one might engage in transmission of UDP packets) on unconfigured interfaces, or even the handling of broadcast addressing on configured interfaces.

There are a few things that DHCP servers, relays, and clients all need to do in order to speak the DHCP protocol in strict compliance with [RFC2131] (Droms, R., “Dynamic Host Configuration Protocol,” March 1997.).

1. Transmit a UDP packet from IP:0.0.0.0 Ethernet:Self, destined to IP:255.255.255.255 LinkLayer:Broadcast on an unconfigured (no IP address yet) interface.
2. Receive a UDP packet from IP:remote-system LinkLayer:remote-system, destined to IP:255.255.255.255 LinkLayer:Broadcast, again on an unconfigured interface.
3. Transmit a UDP packet from IP:Self, Ethernet:Self, destined to IP:remote-system LinkLayer:remote-system, without transmitting a single ARP.
4. And of course the simple case, a regular IP unicast that is routed via the usual means (so it may be direct to a local system, with ARP providing the glue, or it may be to a remote system via one or more routers as normal). In this case, the interfaces are always configured.

The above isn't as simple as it sounds on a regular BSD socket. Many unix implementations will transmit broadcasts not to 255.255.255.255, but to x.y.z.255 (where x.y.z is the system's local subnet). Such packets are not received by several known DHCP client implementations - and it's not their fault, [RFC2131] (Droms, R., “Dynamic Host Configuration Protocol,” March 1997.) very explicitly demands that these packets' IP destination addresses be set to 255.255.255.255.

Receiving packets sent to 255.255.255.255 isn't a problem on most modern unixes...so long as the interface is configured. When there is no IPv4 address on the interface, things become much more murky.

So, for this convoluted and unfortunate state of affairs in the unix systems of the day ISC DHCP was manufactured, in order to do what it needs not only to implement the reference but to interoperate with other implementations, the software must create some form of raw socket to operate on.

What it actually does is create, for each interface detected on the system, a Berkeley Packet Filter socket (or equivalent), and program it with a filter that brings in only DHCP packets. A "fallback" UDP Berkeley socket is generally also created, a single one no matter how many interfaces. Should the software need to transmit a contrived packet to the local network the packet is formed piece by piece and transmitted via the BPF socket. Hence the need to implement many forms of Link Layer framing and above. The software gets away with not having to implement IP routing tables as well by simply utilizing the aforementioned 'fallback' UDP socket when unicasting between two configured systems is needed.

Modern unixes have opened up some facilities that diminish how much of this sort of nefarious kludgery is necessary, but have not found the state of affairs absolutely resolved. In particular, one might now unicast without ARP by inserting an entry into the ARP cache prior to transmitting. Unconfigured interfaces remain the sticking point, however...on virtually no modern unixes is it possible to receive broadcast packets unless a local IPv4 address has been configured, unless it is done with raw sockets.

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### 3.1. Ethernet Protocol References

ISC DHCP Implements Ethernet Version 2 ("DIX"), which is a variant of IEEE 802.2. No good reference of this framing is known to exist at this time, but it is vaguely described in [RFC0894] (Hornig, C., “Standard for the transmission of IP datagrams over Ethernet networks,” April 1984.) see the section titled "Packet format"), and the following URL is also thought to be useful.

http://en.wikipedia.org/wiki/DIX_Ethernet

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### 3.2. Token Ring Protocol References

IEEE 802.5 defines the Token Ring framing format used by ISC DHCP.

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### 3.3. FDDI Protocol References

[RFC1188] (Katz, D., “Proposed Standard for the Transmission of IP Datagrams over FDDI Networks,” October 1990.) is the most helpful reference ISC DHCP has used to form FDDI packets.

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### 3.4. Internet Protocol Version 4 References

RFC760 (Postel, J., “DoD standard Internet Protocol,” January 1980.) [RFC0760] fundamentally defines the bare IPv4 protocol which ISC DHCP implements.

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### 3.5. Unicast Datagram Protocol References

RFC768 (Postel, J., “User Datagram Protocol,” August 1980.) [RFC0768] defines the User Datagram Protocol that ultimately carries the DHCP or BOOTP protocol. The destination DHCP server port is 67, the client port is 68. Source ports are irrelevant.

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### 4. BOOTP Protocol References

The DHCP Protocol is strange among protocols in that it is grafted over the top of another protocol - BOOTP (but we don't call it "DHCP over BOOTP" like we do, say "TCP over IP"). BOOTP and DHCP share UDP packet formats - DHCP is merely a conventional use of both BOOTP header fields and the trailing 'options' space.

The ISC DHCP server supports BOOTP clients conforming to RFC951 (Croft, B. and J. Gilmore, “Bootstrap Protocol,” September 1985.) [RFC0951] and RFC1542 (Wimer, W., “Clarifications and Extensions for the Bootstrap Protocol,” October 1993.) [RFC1542].

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### 5. DHCPv4 Protocol References

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### 5.1. DHCPv4 Protocol

"The DHCP[v4] Protocol" is not defined in a single document. The following collection of references of what ISC DHCP terms "The DHCPv4 Protocol".

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### 5.1.1. Core Protocol References

RFC2131 (Droms, R., “Dynamic Host Configuration Protocol,” March 1997.) [RFC2131] defines the protocol format and procedures. ISC DHCP is not known to diverge from this document in any way. There are, however, a few points on which different implementations have arisen out of vagueries in the document. DHCP Clients exist which, at one time, present themselves as using a Client Identifier Option which is equal to the client's hardware address. Later, the client transmits DHCP packets with no Client Identifier Option present - essentially identifying themselves using the hardware address. Some DHCP Servers have been developed which identify this client as a single client. ISC has interpreted RFC2131 to indicate that these clients must be treated as two separate entities (and hence two, separate addresses). Client behaviour (Embedded Windows products) has developed that relies on the former implementation, and hence is incompatible with the latter. Also, RFC2131 demands explicitly that some header fields be zeroed upon certain message types. The ISC DHCP Server instead copies many of these fields from the packet received from the client or relay, which may not be zero. It is not known if there is a good reason for this that has not been documented.

RFC2132 (Alexander, S. and R. Droms, “DHCP Options and BOOTP Vendor Extensions,” March 1997.) [RFC2132] defines the initial set of DHCP Options and provides a great deal of guidance on how to go about formatting and processing options. The document unfortunately waffles to a great extent about the NULL termination of DHCP Options, and some DHCP Clients (Windows 95) have been implemented that rely upon DHCP Options containing text strings to be NULL-terminated (or else they crash). So, ISC DHCP detects if clients null-terminate the host-name option and, if so, null terminates any text options it transmits to the client. It also removes NULL termination from any known text option it receives prior to any other processing.

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### 5.2. DHCPv4 Option References

RFC2241 (Provan, D., “DHCP Options for Novell Directory Services,” November 1997.) [RFC2241] defines options for Novell Directory Services.

RFC2242 (Droms, R. and K. Fong, “NetWare/IP Domain Name and Information,” November 1997.) [RFC2242] defines an encapsulated option space for NWIP configuration.

RFC2485 (Drach, S., “DHCP Option for The Open Group's User Authentication Protocol,” January 1999.) [RFC2485] defines the Open Group's UAP option.

RFC2610 (Perkins, C. and E. Guttman, “DHCP Options for Service Location Protocol,” June 1999.) [RFC2610] defines options for the Service Location Protocol (SLP).

RFC2937 (Smith, C., “The Name Service Search Option for DHCP,” September 2000.) [RFC2937] defines the Name Service Search Option (not to be confused with the domain-search option). The Name Service Search Option allows eg nsswitch.conf to be reconfigured via dhcp. The ISC DHCP server implements this option, and the ISC DHCP client is compatible...but does not by default install this option's value. One would need to make their relevant dhclient-script process this option in a way that is suitable for the system.

RFC3004 (Stump, G., Droms, R., Gu, Y., Vyaghrapuri, R., Demirtjis, A., Beser, B., and J. Privat, “The User Class Option for DHCP,” November 2000.) [RFC3004] defines the User-Class option. Note carefully that ISC DHCP currently does not implement to this reference, but has (inexplicably) selected an incompatible format: a plain text string.

RFC3011 (Waters, G., “The IPv4 Subnet Selection Option for DHCP,” November 2000.) [RFC3011] defines the Subnet-Selection plain DHCPv4 option. Do not confuse this option with the relay agent "link selection" sub-option, although their behaviour is similar.

RFC3396 (Lemon, T. and S. Cheshire, “Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4),” November 2002.) [RFC3396] documents both how long options may be encoded in DHCPv4 packets, and also how multiple instances of the same option code within a DHCPv4 packet will be decoded by receivers.

RFC3397 (Aboba, B. and S. Cheshire, “Dynamic Host Configuration Protocol (DHCP) Domain Search Option,” November 2002.) [RFC3397] documents the Domain-Search Option, which allows the configuration of the /etc/resolv.conf 'search' parameter in a way that is RFC1035 (Mockapetris, P., “Domain names - implementation and specification,” November 1987.) [RFC1035] wire format compatible (in fact, it uses the RFC1035 wire format). ISC DHCP has both client and server support, and supports RFC1035 name compression.

RFC3679 (Droms, R., “Unused Dynamic Host Configuration Protocol (DHCP) Option Codes,” January 2004.) [RFC3679] documents a number of options that were documented earlier in history, but were not made use of.

RFC3925 (Littlefield, J., “Vendor-Identifying Vendor Options for Dynamic Host Configuration Protocol version 4 (DHCPv4),” October 2004.) [RFC3925] documents a pair of Enterprise-ID delimited option spaces for vendors to use in order to inform servers of their "vendor class" (sort of like 'uname' or 'who and what am I'), and a means to deliver vendor-specific and vendor-documented option codes and values.

RFC3942 (Volz, B., “Reclassifying Dynamic Host Configuration Protocol version 4 (DHCPv4) Options,” November 2004.) [RFC3942] redefined the 'site local' option space.

[RFC4280] (Chowdhury, K., Yegani, P., and L. Madour, “Dynamic Host Configuration Protocol (DHCP) Options for Broadcast and Multicast Control Servers,” November 2005.) defines two BCMS server options for each protocol family.

RFC4388 (Woundy, R. and K. Kinnear, “Dynamic Host Configuration Protocol (DHCP) Leasequery,” February 2006.) [RFC4388] defined the DHCPv4 LEASEQUERY message type and a number of suitable response messages, for the purpose of sharing information about DHCP served addresses and clients.

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### 5.2.1. Relay Agent Information Option Options

RFC3046 (Patrick, M., “DHCP Relay Agent Information Option,” January 2001.) [RFC3046] defines the Relay Agent Information Option and provides a number of sub-option definitions.

RFC3256 (Jones, D. and R. Woundy, “The DOCSIS (Data-Over-Cable Service Interface Specifications) Device Class DHCP (Dynamic Host Configuration Protocol) Relay Agent Information Sub-option,” April 2002.) [RFC3256] defines the DOCSIS Device Class sub-option.

RFC3527 (Kinnear, K., Stapp, M., Johnson, R., and J. Kumarasamy, “Link Selection sub-option for the Relay Agent Information Option for DHCPv4,” April 2003.) [RFC3527] defines the Link Selection sub-option.

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### 5.2.2. Dynamic DNS Updates References

The collection of documents that describe the standards-based method to update dns names of DHCP clients starts most easily with RFC4703 (Stapp, M. and B. Volz, “Resolution of Fully Qualified Domain Name (FQDN) Conflicts among Dynamic Host Configuration Protocol (DHCP) Clients,” October 2006.) [RFC4703] to define the overall architecture, travels through RFCs 4702 (Stapp, M., Volz, B., and Y. Rekhter, “The Dynamic Host Configuration Protocol (DHCP) Client Fully Qualified Domain Name (FQDN) Option,” October 2006.) [RFC4702] and 4704 (Volz, B., “The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN) Option,” October 2006.) [RFC4704] to describe the DHCPv4 and DHCPv6 FQDN options (to carry the client name), and ends up at RFC4701 (Stapp, M., Lemon, T., and A. Gustafsson, “A DNS Resource Record (RR) for Encoding Dynamic Host Configuration Protocol (DHCP) Information (DHCID RR),” October 2006.) [RFC4701] which describes the DHCID RR used in DNS to perform a kind of atomic locking.

ISC DHCP adopted early versions of these documents, and has not yet synchronized with the final standards versions.

For RFCs 4702 and 4704, the 'N' bit is not yet supported. The result is that it is always set zero, and is ignored if set.

For RFC4701, which is used to match client identities with names in the DNS as part of name conflict resolution. Note that ISC DHCP's implementation of DHCIDs vary wildly from this specification. First, ISC DHCP uses a TXT record in which the contents are stored in hexadecimal. Second, there is a flaw in the selection of the 'Identifier Type', which results in a completely different value being selected than was defined in an older revision of this document...also this field is one byte prior to hexadecimal encoding rather than two. Third, ISC DHCP does not use a digest type code. Rather, all values for such TXT records are reached via an MD5 sum. In short, nothing is compatible, but the principle of the TXT record is the same as the standard DHCID record. However, for DHCPv6 FQDN, we do use DHCID type code '2', as no other value really makes sense in our context.

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### 5.2.3. Experimental: Failover References

The Failover Protocol defines means by which two DHCP Servers can share all the relevant information about leases granted to DHCP clients on given networks, so that one of the two servers may fail and be survived by a server that can act responsibly.

Unfortunately it has been quite some years (2003) since the last time this document was edited, and the authors no longer show any interest in fielding comments or improving the document.

The status of this protocol is very unsure, but ISC's implementation of it has proven stable and suitable for use in sizable production environments.

draft-ietf-dhc-failover-12.txt (Droms, R., “DHCP Failover Protocol,” March 2003.) [draft‑failover] describes the Failover Protocol. In addition to what is described in this document, ISC DHCP has elected to make some experimental changes that may be revoked in a future version of ISC DHCP (if the draft authors do not adopt the new behaviour). Specifically, ISC DHCP's POOLREQ behaviour differs substantially from what is documented in the draft, and the server also implements a form of 'MAC Address Affinity' which is not described in the failover document. The full nature of these changes have been described on the IETF DHC WG mailing list (which has archives), and also in ISC DHCP's manual pages. Also note that although this document references a RECOVER-WAIT state, it does not document a protocol number assignment for this state. As a consequence, ISC DHCP has elected to use the value 254.

An optimization described in the failover protocol draft is included since 4.2.0a1. It permits a DHCP server operating in communications-interrupted state to 'rewind' a lease to the state most recently transmitted to its peer, greatly increasing a server's endurance in communications-interrupted. This is supported using a new 'rewind state' record on the dhcpd.leases entry for each lease.

[RFC3074] (Volz, B., Gonczi, S., Lemon, T., and R. Stevens, “DHC Load Balancing Algorithm,” February 2001.) describes the Load Balancing Algorithm (LBA) that ISC DHCP uses in concert with the Failover protocol. Note that versions 3.0.* are known to misimplement the hash algorithm (it will only use the low 4 bits of every byte of the hash bucket array).

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### 5.3. DHCP Procedures

[RFC2939] (Droms, R., “Procedures and IANA Guidelines for Definition of New DHCP Options and Message Types,” September 2000.) explains how to go about obtaining a new DHCP Option code assignment.

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### 6. DHCPv6 Protocol References

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### 6.1. DHCPv6 Protocol References

For now there is only one document that specifies the base of the DHCPv6 protocol (there have been no updates yet), [RFC3315] (Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, “Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” July 2003.).

Support for DHCPv6 was first added in version 4.0.0. The server and client support only IA_NA. While the server does support multiple IA_NAs within one packet from the client, our client only supports sending one. There is no relay support.

DHCPv6 introduces some new and uncomfortable ideas to the common software library.

1. Options sometimes may appear multiple times. The common library used to treat all appearance of multiple options as specified in RFC2131 - to be concatenated. DHCPv6 options may sometimes appear multiple times (such as with IA_NA or IAADDR), but often must not. As of 4.2.1-P1, multiple IA_NA, IA_PD or IA_TA are not supported.
2. The same option space appears in DHCPv6 packets multiple times. If the packet was got via a relay, then the client's packet is stored to an option within the relay's packet...if there were two relays, this recurses. At each of these steps, the root "DHCPv6 option space" is used. Further, a client packet may contain an IA_NA, which may contain an IAADDR - but really, in an abstract sense, this is again re-encapsulation of the DHCPv6 option space beneath options it also contains.

Precisely how to correctly support the above conundrums has not quite yet been settled, so support is incomplete.

[RFC5453] (Krishnan, S., “Reserved IPv6 Interface Identifiers,” February 2009.) creates a registry at IANA to reserve interface identifiers and specifies a starting set. These IIDs should not be used when constructing addresses to avoid possible conflicts.

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### 6.2. DHCPv6 Options References

[RFC3319] (Schulzrinne, H. and B. Volz, “Dynamic Host Configuration Protocol (DHCPv6) Options for Session Initiation Protocol (SIP) Servers,” July 2003.) defines the SIP server options for DHCPv6.

[RFC3646] (Droms, R., “DNS Configuration options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” December 2003.) documents the DHCPv6 name-servers and domain-search options.

[RFC3633] (Troan, O. and R. Droms, “IPv6 Prefix Options for Dynamic Host Configuration Protocol (DHCP) version 6,” December 2003.) documents the Identity Association Prefix Delegation for DHCPv6, which is included here for protocol wire reference, but which is not supported by ISC DHCP.

[RFC3898] (Kalusivalingam, V., “Network Information Service (NIS) Configuration Options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” October 2004.) documents four NIS options for delivering NIS servers and domain information in DHCPv6.

[RFC4075] (Kalusivalingam, V., “Simple Network Time Protocol (SNTP) Configuration Option for DHCPv6,” May 2005.) defines the DHCPv6 SNTP Servers option.

[RFC4242] (Venaas, S., Chown, T., and B. Volz, “Information Refresh Time Option for Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” November 2005.) defines the Information Refresh Time option, which advises DHCPv6 Information-Request clients to return for updated information.

[RFC4280] (Chowdhury, K., Yegani, P., and L. Madour, “Dynamic Host Configuration Protocol (DHCP) Options for Broadcast and Multicast Control Servers,” November 2005.) defines two BCMS server options for each protocol family.

[RFC4580] (Volz, B., “Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Relay Agent Subscriber-ID Option,” June 2006.) defines a DHCPv6 subscriber-id option, which is similar in principle to the DHCPv4 relay agent option of the same name.

[RFC4649] (Volz, B., “Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Relay Agent Remote-ID Option,” August 2006.) defines a DHCPv6 remote-id option, which is similar in principle to the DHCPv4 relay agent remote-id.

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### 7. References

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### 7.1. Published DHCPv4 References

[RFC0760] | Postel, J., “DoD standard Internet Protocol,” RFC 760, January 1980 (TXT).
[RFC0768] | Postel, J., “User Datagram Protocol,” STD 6, RFC 768, August 1980 (TXT).
[RFC0894] | Hornig, C., “Standard for the transmission of IP datagrams over Ethernet networks,” STD 41, RFC 894, April 1984 (TXT).
[RFC0951] | Croft, B. and J. Gilmore, “Bootstrap Protocol,” RFC 951, September 1985 (TXT).
[RFC1035] | Mockapetris, P., “Domain names - implementation and specification,” STD 13, RFC 1035, November 1987 (TXT).
[RFC1188] | Katz, D., “Proposed Standard for the Transmission of IP Datagrams over FDDI Networks,” RFC 1188, October 1990 (TXT).
[RFC1542] | Wimer, W., “Clarifications and Extensions for the Bootstrap Protocol,” RFC 1542, October 1993 (TXT).
[RFC2131] | Droms, R., “Dynamic Host Configuration Protocol,” RFC 2131, March 1997 (TXT, HTML, XML).
[RFC2132] | Alexander, S. and R. Droms, “DHCP Options and BOOTP Vendor Extensions,” RFC 2132, March 1997 (TXT, HTML, XML).
[RFC2241] | Provan, D., “DHCP Options for Novell Directory Services,” RFC 2241, November 1997 (TXT, HTML, XML).
[RFC2242] | Droms, R. and K. Fong, “NetWare/IP Domain Name and Information,” RFC 2242, November 1997 (TXT, HTML, XML).
[RFC2485] | Drach, S., “DHCP Option for The Open Group's User Authentication Protocol,” RFC 2485, January 1999 (TXT, HTML, XML).
[RFC2563] | Troll, R., “DHCP Option to Disable Stateless Auto-Configuration in IPv4 Clients,” RFC 2563, May 1999 (TXT).
[RFC2610] | Perkins, C. and E. Guttman, “DHCP Options for Service Location Protocol,” RFC 2610, June 1999 (TXT).
[RFC2855] | Fujisawa, K., “DHCP for IEEE 1394,” RFC 2855, June 2000 (TXT).
[RFC2937] | Smith, C., “The Name Service Search Option for DHCP,” RFC 2937, September 2000 (TXT).
[RFC2939] | Droms, R., “Procedures and IANA Guidelines for Definition of New DHCP Options and Message Types,” BCP 43, RFC 2939, September 2000 (TXT).
[RFC3004] | Stump, G., Droms, R., Gu, Y., Vyaghrapuri, R., Demirtjis, A., Beser, B., and J. Privat, “The User Class Option for DHCP,” RFC 3004, November 2000 (TXT).
[RFC3011] | Waters, G., “The IPv4 Subnet Selection Option for DHCP,” RFC 3011, November 2000 (TXT).
[RFC3046] | Patrick, M., “DHCP Relay Agent Information Option,” RFC 3046, January 2001 (TXT).
[RFC3074] | Volz, B., Gonczi, S., Lemon, T., and R. Stevens, “DHC Load Balancing Algorithm,” RFC 3074, February 2001 (TXT).
[RFC3118] | Droms, R. and W. Arbaugh, “Authentication for DHCP Messages,” RFC 3118, June 2001 (TXT).
[RFC3203] | T'Joens, Y., Hublet, C., and P. De Schrijver, “DHCP reconfigure extension,” RFC 3203, December 2001 (TXT).
[RFC3256] | Jones, D. and R. Woundy, “The DOCSIS (Data-Over-Cable Service Interface Specifications) Device Class DHCP (Dynamic Host Configuration Protocol) Relay Agent Information Sub-option,” RFC 3256, April 2002 (TXT).
[RFC3361] | Schulzrinne, H., “Dynamic Host Configuration Protocol (DHCP-for-IPv4) Option for Session Initiation Protocol (SIP) Servers,” RFC 3361, August 2002 (TXT).
[RFC3396] | Lemon, T. and S. Cheshire, “Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4),” RFC 3396, November 2002 (TXT).
[RFC3397] | Aboba, B. and S. Cheshire, “Dynamic Host Configuration Protocol (DHCP) Domain Search Option,” RFC 3397, November 2002 (TXT).
[RFC3442] | Lemon, T., Cheshire, S., and B. Volz, “The Classless Static Route Option for Dynamic Host Configuration Protocol (DHCP) version 4,” RFC 3442, December 2002 (TXT).
[RFC3456] | Patel, B., Aboba, B., Kelly, S., and V. Gupta, “Dynamic Host Configuration Protocol (DHCPv4) Configuration of IPsec Tunnel Mode,” RFC 3456, January 2003 (TXT).
[RFC3495] | Beser, B. and P. Duffy, “Dynamic Host Configuration Protocol (DHCP) Option for CableLabs Client Configuration,” RFC 3495, March 2003 (TXT).
[RFC3527] | Kinnear, K., Stapp, M., Johnson, R., and J. Kumarasamy, “Link Selection sub-option for the Relay Agent Information Option for DHCPv4,” RFC 3527, April 2003 (TXT).
[RFC3594] | Duffy, P., “PacketCable Security Ticket Control Sub-Option for the DHCP CableLabs Client Configuration (CCC) Option,” RFC 3594, September 2003 (TXT).
[RFC3634] | Luehrs, K., Woundy, R., Bevilacqua, J., and N. Davoust, “Key Distribution Center (KDC) Server Address Sub-option for the Dynamic Host Configuration Protocol (DHCP) CableLabs Client Configuration (CCC) Option,” RFC 3634, December 2003 (TXT).
[RFC3679] | Droms, R., “Unused Dynamic Host Configuration Protocol (DHCP) Option Codes,” RFC 3679, January 2004 (TXT).
[RFC3825] | Polk, J., Schnizlein, J., and M. Linsner, “Dynamic Host Configuration Protocol Option for Coordinate-based Location Configuration Information,” RFC 3825, July 2004 (TXT).
[RFC3925] | Littlefield, J., “Vendor-Identifying Vendor Options for Dynamic Host Configuration Protocol version 4 (DHCPv4),” RFC 3925, October 2004 (TXT).
[RFC3942] | Volz, B., “Reclassifying Dynamic Host Configuration Protocol version 4 (DHCPv4) Options,” RFC 3942, November 2004 (TXT).
[RFC3993] | Johnson, R., Palaniappan, T., and M. Stapp, “Subscriber-ID Suboption for the Dynamic Host Configuration Protocol (DHCP) Relay Agent Option,” RFC 3993, March 2005 (TXT).
[RFC4014] | Droms, R. and J. Schnizlein, “Remote Authentication Dial-In User Service (RADIUS) Attributes Suboption for the Dynamic Host Configuration Protocol (DHCP) Relay Agent Information Option,” RFC 4014, February 2005 (TXT).
[RFC4030] | Stapp, M. and T. Lemon, “The Authentication Suboption for the Dynamic Host Configuration Protocol (DHCP) Relay Agent Option,” RFC 4030, March 2005 (TXT).
[RFC4039] | Park, S., Kim, P., and B. Volz, “Rapid Commit Option for the Dynamic Host Configuration Protocol version 4 (DHCPv4),” RFC 4039, March 2005 (TXT).
[RFC4174] | Monia, C., Tseng, J., and K. Gibbons, “The IPv4 Dynamic Host Configuration Protocol (DHCP) Option for the Internet Storage Name Service,” RFC 4174, September 2005 (TXT).
[RFC4243] | Stapp, M., Johnson, R., and T. Palaniappan, “Vendor-Specific Information Suboption for the Dynamic Host Configuration Protocol (DHCP) Relay Agent Option,” RFC 4243, December 2005 (TXT).
[RFC4361] | Lemon, T. and B. Sommerfeld, “Node-specific Client Identifiers for Dynamic Host Configuration Protocol Version Four (DHCPv4),” RFC 4361, February 2006 (TXT).
[RFC4388] | Woundy, R. and K. Kinnear, “Dynamic Host Configuration Protocol (DHCP) Leasequery,” RFC 4388, February 2006 (TXT).
[RFC4390] | Kashyap, V., “Dynamic Host Configuration Protocol (DHCP) over InfiniBand,” RFC 4390, April 2006 (TXT).
[RFC4436] | Aboba, B., Carlson, J., and S. Cheshire, “Detecting Network Attachment in IPv4 (DNAv4),” RFC 4436, March 2006 (TXT).
[RFC4701] | Stapp, M., Lemon, T., and A. Gustafsson, “A DNS Resource Record (RR) for Encoding Dynamic Host Configuration Protocol (DHCP) Information (DHCID RR),” RFC 4701, October 2006 (TXT).
[RFC4702] | Stapp, M., Volz, B., and Y. Rekhter, “The Dynamic Host Configuration Protocol (DHCP) Client Fully Qualified Domain Name (FQDN) Option,” RFC 4702, October 2006 (TXT).
[RFC4703] | Stapp, M. and B. Volz, “Resolution of Fully Qualified Domain Name (FQDN) Conflicts among Dynamic Host Configuration Protocol (DHCP) Clients,” RFC 4703, October 2006 (TXT).
[RFC5010] | Kinnear, K., Normoyle, M., and M. Stapp, “The Dynamic Host Configuration Protocol Version 4 (DHCPv4) Relay Agent Flags Suboption,” RFC 5010, September 2007 (TXT).
[RFC5071] | Hankins, D., “Dynamic Host Configuration Protocol Options Used by PXELINUX,” RFC 5071, December 2007 (TXT).
[RFC5107] | Johnson, R., Kumarasamy, J., Kinnear, K., and M. Stapp, “DHCP Server Identifier Override Suboption,” RFC 5107, February 2008 (TXT).
[RFC5192] | Morand, L., Yegin, A., Kumar, S., and S. Madanapalli, “DHCP Options for Protocol for Carrying Authentication for Network Access (PANA) Authentication Agents,” RFC 5192, May 2008 (TXT).
[RFC5223] | Schulzrinne, H., Polk, J., and H. Tschofenig, “Discovering Location-to-Service Translation (LoST) Servers Using the Dynamic Host Configuration Protocol (DHCP),” RFC 5223, August 2008 (TXT).
[RFC5859] | Johnson, R., “TFTP Server Address Option for DHCPv4,” RFC 5859, June 2010 (TXT).
[RFC5969] | Townsley, W. and O. Troan, “IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) -- Protocol Specification,” RFC 5969, August 2010 (TXT).
[draft-failover] | Droms, R., “DHCP Failover Protocol,” March 2003.
[I-D.ietf-dhc-dhcpv4-relay-encapsulation] | Lemon, T. and H. Deng, “Relay Agent Encapsulation for DHCPv4,” draft-ietf-dhc-dhcpv4-relay-encapsulation-00 (work in progress), October 2010 (TXT).
[I-D.ietf-dhc-dhcpv4-bulk-leasequery] | Kinnear, K., Volz, B., Russell, N., Stapp, M., Rao, D., Joshi, B., and P. Kurapati, “Bulk DHCPv4 Lease Query,” draft-ietf-dhc-dhcpv4-bulk-leasequery-03 (work in progress), October 2010 (TXT).
[I-D.ietf-dhc-leasequery-by-remote-id] | Kurapati, P. and B. Joshi, “DHCPv4 lease query by Relay Agent Remote ID,” draft-ietf-dhc-leasequery-by-remote-id-09 (work in progress), December 2010 (TXT).
[I-D.ietf-dhc-relay-id-suboption] | Stapp, M., “The DHCPv4 Relay Agent Identifier Suboption,” draft-ietf-dhc-relay-id-suboption-07 (work in progress), July 2009 (TXT).
[I-D.ietf-mip6-hiopt] | Jang, H., Yegin, A., Chowdhury, K., and J. Choi, “DHCP Options for Home Information Discovery in MIPv6,” draft-ietf-mip6-hiopt-17 (work in progress), May 2008 (TXT).

TOC

### 7.2. Published Common (DHCPv4/DHCPv6) References

[RFC4280] | Chowdhury, K., Yegani, P., and L. Madour, “Dynamic Host Configuration Protocol (DHCP) Options for Broadcast and Multicast Control Servers,” RFC 4280, November 2005 (TXT).
[RFC4477] | Chown, T., Venaas, S., and C. Strauf, “Dynamic Host Configuration Protocol (DHCP): IPv4 and IPv6 Dual-Stack Issues,” RFC 4477, May 2006 (TXT).
[RFC4578] | Johnston, M. and S. Venaas, “Dynamic Host Configuration Protocol (DHCP) Options for the Intel Preboot eXecution Environment (PXE),” RFC 4578, November 2006 (TXT).
[RFC4776] | Schulzrinne, H., “Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information,” RFC 4776, November 2006 (TXT).
[RFC4833] | Lear, E. and P. Eggert, “Timezone Options for DHCP,” RFC 4833, April 2007 (TXT).
[RFC5417] | Calhoun, P., “Control And Provisioning of Wireless Access Points (CAPWAP) Access Controller DHCP Option,” RFC 5417, March 2009 (TXT).
[RFC5678] | Bajko, G. and S. Das, “Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Options for IEEE 802.21 Mobility Services (MoS) Discovery,” RFC 5678, December 2009 (TXT).
[RFC5908] | Gayraud, R. and B. Lourdelet, “Network Time Protocol (NTP) Server Option for DHCPv6,” RFC 5908, June 2010 (TXT).
[RFC5970] | Huth, T., Freimann, J., Zimmer, V., and D. Thaler, “DHCPv6 Options for Network Boot,” RFC 5970, September 2010 (TXT).
[RFC5986] | Thomson, M. and J. Winterbottom, “Discovering the Local Location Information Server (LIS),” RFC 5986, September 2010 (TXT).
[I-D.ietf-dhc-vpn-option] | Kinnear, K., Johnson, R., and M. Stapp, “Virtual Subnet Selection Options for DHCPv4 and DHCPv6,” draft-ietf-dhc-vpn-option-12 (work in progress), October 2010 (TXT).

TOC

### 7.3. Published DHCPv6 References

[RFC3315] | Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, “Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” RFC 3315, July 2003 (TXT).
[RFC3319] | Schulzrinne, H. and B. Volz, “Dynamic Host Configuration Protocol (DHCPv6) Options for Session Initiation Protocol (SIP) Servers,” RFC 3319, July 2003 (TXT).
[RFC3633] | Troan, O. and R. Droms, “IPv6 Prefix Options for Dynamic Host Configuration Protocol (DHCP) version 6,” RFC 3633, December 2003 (TXT).
[RFC3646] | Droms, R., “DNS Configuration options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” RFC 3646, December 2003 (TXT).
[RFC3736] | Droms, R., “Stateless Dynamic Host Configuration Protocol (DHCP) Service for IPv6,” RFC 3736, April 2004 (TXT).
[RFC3898] | Kalusivalingam, V., “Network Information Service (NIS) Configuration Options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” RFC 3898, October 2004 (TXT).
[RFC4075] | Kalusivalingam, V., “Simple Network Time Protocol (SNTP) Configuration Option for DHCPv6,” RFC 4075, May 2005 (TXT).
[RFC4076] | Chown, T., Venaas, S., and A. Vijayabhaskar, “Renumbering Requirements for Stateless Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” RFC 4076, May 2005 (TXT).
[RFC4242] | Venaas, S., Chown, T., and B. Volz, “Information Refresh Time Option for Dynamic Host Configuration Protocol for IPv6 (DHCPv6),” RFC 4242, November 2005 (TXT).
[RFC4580] | Volz, B., “Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Relay Agent Subscriber-ID Option,” RFC 4580, June 2006 (TXT).
[RFC4649] | Volz, B., “Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Relay Agent Remote-ID Option,” RFC 4649, August 2006 (TXT).
[RFC4704] | Volz, B., “The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN) Option,” RFC 4704, October 2006 (TXT).
[RFC4994] | Zeng, S., Volz, B., Kinnear, K., and J. Brzozowski, “DHCPv6 Relay Agent Echo Request Option,” RFC 4994, September 2007 (TXT).
[RFC5007] | Brzozowski, J., Kinnear, K., Volz, B., and S. Zeng, “DHCPv6 Leasequery,” RFC 5007, September 2007 (TXT).
[RFC5453] | Krishnan, S., “Reserved IPv6 Interface Identifiers,” RFC 5453, February 2009 (TXT).
[RFC5460] | Stapp, M., “DHCPv6 Bulk Leasequery,” RFC 5460, February 2009 (TXT).
[I-D.ietf-mif-dhcpv6-route-option] | Dec, W., Mrugalski, T., Sun, T., and B. Sarikaya, “DHCPv6 Route Options,” draft-ietf-mif-dhcpv6-route-option-03 (work in progress), September 2011 (TXT).
[I-D.ietf-dhc-dhcpv6-ldra] | Miles, D., Ooghe, S., Dec, W., Krishnan, S., and A. Kavanagh, “Lightweight DHCPv6 Relay Agent,” draft-ietf-dhc-dhcpv6-ldra-03 (work in progress), October 2010 (TXT).
[I-D.ietf-dhc-dhcpv6-relay-supplied-options] | Lemon, T. and W. Wu, “Relay-Supplied DHCP Options,” draft-ietf-dhc-dhcpv6-relay-supplied-options-09 (work in progress), September 2011 (TXT).
[I-D.ietf-dhc-pd-exclude] | Korhonen, J., Savolainen, T., Krishnan, S., and O. Troan, “Prefix Exclude Option for DHCPv6-based Prefix Delegation,” draft-ietf-dhc-pd-exclude-01 (work in progress), January 2011 (TXT).
[I-D.ietf-dhc-secure-dhcpv6] | Jiang, S., “Secure DHCPv6 Using CGAs,” draft-ietf-dhc-secure-dhcpv6-02 (work in progress), December 2010 (TXT).
[I-D.ietf-mext-nemo-pd] | Droms, R., Thubert, P., Dupont, F., Haddad, W., and C. Bernardos, “DHCPv6 Prefix Delegation for NEMO,” draft-ietf-mext-nemo-pd-07 (work in progress), December 2010 (TXT).
[I-D.ietf-dhc-duid-uuid] | Narten, T. and J. Johnson, “Definition of the UUID-based DHCPv6 Unique Identifier (DUID-UUID),” draft-ietf-dhc-duid-uuid-03 (work in progress), February 2011 (TXT).
[I-D.ietf-softwire-ds-lite-tunnel-option] | Hankins, D. and T. Mrugalski, “Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Option for Dual- Stack Lite,” draft-ietf-softwire-ds-lite-tunnel-option-10 (work in progress), March 2011 (TXT).
[I-D.ietf-mif-dns-server-selection] | Savolainen, T. and J. Kato, “Improved DNS Server Selection for Multi-Homed Nodes,” draft-ietf-mif-dns-server-selection-01 (work in progress), March 2011 (TXT).
[I-D.ietf-geopriv-rfc3825bis] | Polk, J., Linsner, M., Thomson, M., and B. Aboba, “Dynamic Host Configuration Protocol Options for Coordinate-based Location Configuration Information,” draft-ietf-geopriv-rfc3825bis-17 (work in progress), February 2011 (TXT).
[draft-addr-params] | Mrugalski, T., “Address Parameters Option for DHCPv6,” April 2007.

TOC

### Authors' Addresses

| David W. Hankins
| Internet Systems Consortium, Inc.
| 950 Charter Street
| Redwood City, CA 94063
| Tomasz Mrugalski
| Internet Systems Consortium, Inc.
| 950 Charter Street
| Redwood City, CA 94063
Phone: | +1 650 423 1345
Email: | Tomasz_Mrugalski@isc.org