draft-ietf-dhc-3315id-for-v4-04.txt   draft-ietf-dhc-3315id-for-v4-05.txt 
DHC Working Group Ted Lemon DHC Working Group Ted Lemon
INTERNET DRAFT Nominum INTERNET DRAFT Nominum
Expires: July 2005 Bill Sommerfeld Expires: January 2006 Bill Sommerfeld
Internet Draft Sun Microsystems Internet Draft Sun Microsystems
Document: <draft-ietf-dhc-3315id-for-v4-04.txt> Document: <draft-ietf-dhc-3315id-for-v4-05.txt>
Category: Standards Track February, 2005 Updates: 2131, 2132, 3315
Category: Standards Track June, 2005
Node-Specific Client Identifiers for DHCPv4 Node-Specific Client Identifiers for DHCPv4
Status of this Memo Status of this Memo
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disclosed, in accordance with RFC 3668. aware will be disclosed, in accordance with Section 6 of BCP 79.
This document is a submission by the Dynamic Host Configuration This document is a submission by the Dynamic Host Configuration
Working Group of the Internet Engineering Task Force (IETF). Comments Working Group of the Internet Engineering Task Force (IETF). Comments
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Abstract Abstract
This document specifies the format that is to be used for encoding This document specifies the format that is to be used for encoding
DHCPv4 [RFC2131 and RFC2132] client identifiers, so that those DHCPv4 client identifiers, so that those identifiers will be inter-
identifiers will be interchangeable with identifiers used in the changeable with identifiers used in the DHCPv6 protocol. This
DHCPv6 protocol [RFC3315]. document also addresses and corrects some problems in RFC2131 and
RFC2132 with respect to the handling of DHCP client identifiers.
Introduction 1. Introduction
This document specifies the way in which DHCPv4 clients should This document specifies the way in which DHCPv4 [RFC2131] clients
identify themselves. DHCPv4 client implementations that conform to should identify themselves. DHCPv4 client implementations that
this specification use a DHCPv6-style DHCP Unique Identifier (DUID) conform to this specification use a DHCPv6-style DHCP Unique
encapsulated in a DHCPv4 client identifier option. This supersedes Identifier (DUID) [RFC3315] encapsulated in a DHCPv4 client
the behaviour specified in RFC2131 and RFC2132. identifier option. This supersedes the behavior specified in
RFC2131 and RFC2132.
The reason for making this change is that as we make the transition The reason for making this change is that as we make the transition
from IPv4 to IPv6, there will be network devices that must use both from IPv4 to IPv6, there will be network devices that must use both
DHCPv4 and DHCPv6. Users of these devices will have a smoother DHCPv4 and DHCPv6. Users of these devices will have a smoother
network experience if the devices identify themselves consistently, network experience if the devices identify themselves consistently,
regardless of the version of DHCP they are using at any given regardless of the version of DHCP they are using at any given
moment. Most obviously, DNS updates made by the DHCP server on moment. Most obviously, DNS updates made by the DHCP server on
behalf of the client will not be handled correctly. This change behalf of the client will be handled more correctly. This change
also addresses certain limitations in the functioning of also addresses certain limitations in the functioning of
RFC2131/2132-style DHCP client identifiers. RFC2131/2132-style DHCP client identifiers.
This document first describes the problem to be solved. It then This document first describes the problem to be solved. It then
states the new technique that is to be used to solve the problem. states the new technique that is to be used to solve the problem.
Finally, it describes the specific changes that one would have to Finally, it describes the specific changes that one would have to
make to RFC2131 and RFC2132 in order for those documents not to make to RFC2131 and RFC2132 in order for those documents not to
contradict what is described in this document. contradict what is described in this document.
1.0 Applicability 2. Terminology
This document updates RFC2131 and RFC2132. DHCPv4 server The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
implementations SHOULD conform to this document. DHCPv4 clients on "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
network devices that are expected to support DHCPv6 in the future document are to be interpreted as described in RFC 2119 [RFC2119].
SHOULD conform to this document. This document makes no changes to
the behavior of DHCPv6 clients or servers. 3. Applicability
This document updates RFC2131 and RFC2132. This document also
specifies behavior that is required of DHCPv4 and DHCPv6 clients
that are intended to operate in a dual-stack configuration.
Finally, this document recommends behavior for host configurations
where more than one DHCP client must operate in sequence in order
to fully configure the client - e.g., a network boot loader and the
operating system it loads.
DHCPv4 clients and servers that are implemented according to this DHCPv4 clients and servers that are implemented according to this
document should be implemented as if the changes specified in document should be implemented as if the changes specified in
section 4.3 and 4.4 have been made to RFC2131 and RFC2132. section 6.3 and 6.4 have been made to RFC2131 and RFC2132. DHCPv4
clients should, in addition, follow the behavior specified in
section 6.1. DHCPv6 clients should follow the behavior specified
in section 6.2. DHCPv4 servers should additionally follow the
behavior specified in section 6.3.
2.0 Problem Statement 4. Problem Statement
2.1. Client identities are ephemeral 4.1. Client identities are ephemeral
RFC2132 recommends that client identifiers be generated by using RFC2132 recommends that client identifiers be generated by using
the permanent link-layer address of the network interface that the the permanent link-layer address of the network interface that the
client is trying to configure. In cases where a network interface client is trying to configure. One result of this recommendation
is removed from the client computer and replaced with a different is that when the network interface hardware on a client computer
network interface with a different permanent link-layer address, is replaced, the identity of the client changes. The client loses
the identity of the client changes. The client loses its IP its IP address and any other resources associated with its old
address and any other resources associated with its old identifier identifier - for example, its domain name as published through the
- for example, its domain name as published through the DHCPv4 DHCPv4 server.
server.
2.2. Clients can accidentally present multiple identities 4.2. Clients can accidentally present multiple identities
Consider a DHCPv4 client that has two network interfaces, one of Consider a DHCPv4 client that has two network interfaces, one of
which is wired and one of which is wireless. The DHCPv4 client which is wired and one of which is wireless. The DHCPv4 client
will succeed in configuring either zero, one, or two network will succeed in configuring either zero, one, or two network
interfaces. Under the current specification, each network interfaces. Under the current specification, each network
interface will receive a different IP address. The DHCPv4 server interface will receive a different IP address. The DHCPv4 server
will treat each network interface as a completely independent will treat each network interface as a completely independent
DHCPv4 client, on a completely independent host. DHCPv4 client, on a completely independent host.
Thus, when the client presents some information to be updated in a Thus, when the client presents some information to be updated in a
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When the user is near a wired outlet, he or she may want the When the user is near a wired outlet, he or she may want the
additional speed and privacy provided by a wired connection, but additional speed and privacy provided by a wired connection, but
that same user may unplug from the wired network and wander around, that same user may unplug from the wired network and wander around,
still connected to the wireless network. When a transition like still connected to the wireless network. When a transition like
this happens, under the current scheme, if the address of the wired this happens, under the current scheme, if the address of the wired
interface is the one that gets published, this client will be seen interface is the one that gets published, this client will be seen
by hosts attempting to connect to it as if it has intermittent by hosts attempting to connect to it as if it has intermittent
connectivity, even though it actually has continuous network connectivity, even though it actually has continuous network
connectivity through the wireless port. connectivity through the wireless port.
2.3. RFC2131/2132 and RFC3315 identifiers are incompatible Another common case of a duplicate identity being presented occurs
when a boot monitor such as a PXE loader specifies one DHCP client
identifier, and then the operating system loaded by the boot loader
specifies a different identity.
4.3. RFC2131/2132 and RFC3315 identifiers are incompatible
The 'client identifier' option is used by DHCPv4 clients and The 'client identifier' option is used by DHCPv4 clients and
servers to identify clients. In some cases, the value of the servers to identify clients. In some cases, the value of the
'client identifier' option is used to mediate access to resources 'client identifier' option is used to mediate access to resources
(for example, the client's domain name, as published through the (for example, the client's domain name, as published through the
DHCPv4 server). RFC2132 and RFC3315 specify different methods for DHCPv4 server). RFC2132 and RFC3315 specify different methods for
deriving client identifiers. These methods guarantee that the deriving client identifiers. These methods guarantee that the
DHCPv4 and DHCPv6 identifier will be different. This means that DHCPv4 and DHCPv6 identifier will be different. This means that
mediation of access to resources using these identifiers will not mediation of access to resources using these identifiers will not
work correctly in cases where a node may be configured using DHCPv4 work correctly in cases where a node may be configured using DHCPv4
in some cases and DHCPv6 in other cases. in some cases and DHCPv6 in other cases.
2.4. RFC2131 does not require the use of a client identifier 4.4. RFC2131 does not require the use of a client identifier
RFC2131 allows the DHCPv4 server to identify clients either by RFC2131 allows the DHCPv4 server to identify clients either by
using the client identifier option sent by the client, or, if the using the client identifier option sent by the client, or, if the
client did not send one, the client's link-layer address. Like the client did not send one, the client's link-layer address. Like the
client identifier format recommended by RFC2131, this suffers from client identifier format recommended by RFC2131, this suffers from
the problems previously described in (2) and (3). the problems previously described in sections 4.2 and 4.3.
3. Requirements 5. Requirements
In order to address the problems stated in section 2, DHCPv4 client In order to address the problems stated in section 4, DHCPv4 client
identifiers must have the following characteristics: identifiers must have the following characteristics:
- They must be persistent, in the sense that a particular host's - They must be persistent, in the sense that a particular host's
client identifier must not change simply because a piece of client identifier must not change simply because a piece of
network hardware is added or removed. network hardware is added or removed.
- It must be possible for the client to represent itself as having - It must be possible for the client to represent itself as having
more than one network identity - for example so that a client more than one network identity - for example so that a client
with two network interfaces can express to the DHCPv4 server that with two network interfaces can express to the DHCPv4 server that
these two network interfaces are to receive different IP these two network interfaces are to receive different IP
addresses, even if they happen to be connected to the same link. addresses, even if they happen to be connected to the same link.
- In cases where the DHCPv4 client is expressing more than one - In cases where the DHCPv4 client is expressing more than one
network identity at the same time, it must nevertheless be network identity at the same time, it must nevertheless be
possible for the DHCPv4 server to determine that the two network possible for the DHCPv4 server to determine that the two network
identities belong to the same host. identities belong to the same host.
- It must be possible for a client that is prepared to handle the - In some cases it may be desirable for a DHCP client to present
case where two or more network interfaces have the same IP the same identity on two interfaces, so that if they both happen
address to use exactly the same identifier for each interface. to be connected to the same network, they will both receive the
same IP address. In such cases, it must be possible for the
client to use exactly the same identifier for each interface.
- DHCPv4 servers that do not conform to this specification, but that - DHCPv4 servers that do not conform to this specification, but that
are compliant with the older client identifier specification, are compliant with the older client identifier specification,
must correctly handle client identifiers sent by clients that must correctly handle client identifiers sent by clients that
conform to this specification. conform to this specification.
- DHCPv4 servers that do conform to this specification must - DHCPv4 servers that do conform to this specification must
interoperate correctly with DHCPv4 clients that do not conform to interoperate correctly with DHCPv4 clients that do not conform to
this specification, except that when configuring such clients, this specification, except that when configuring such clients,
behaviors such as those described in section two may occur. behaviors such as those described in section two may occur.
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client's identity to update the DNS on behalf of a DHCPv4 client client's identity to update the DNS on behalf of a DHCPv4 client
must register the same client identity in the DNS that would be must register the same client identity in the DNS that would be
registered by the DHCPv6 server on behalf of the DHCPv6 client registered by the DHCPv6 server on behalf of the DHCPv6 client
running on that host, and vice versa. running on that host, and vice versa.
In order to satisfy all but the last of these requirements, we need In order to satisfy all but the last of these requirements, we need
to construct a DHCPv4 client identifier out of two parts. One part to construct a DHCPv4 client identifier out of two parts. One part
must be unique to the host on which the client is running. The must be unique to the host on which the client is running. The
other must be unique to the network identity being presented. The other must be unique to the network identity being presented. The
DHCP Unique Identifier (DUID) and Identity Association Identifier DHCP Unique Identifier (DUID) and Identity Association Identifier
(IAID) specified in RFC3315 satisfy these requirements. And in (IAID) specified in RFC3315 satisfy these requirements.
order to satisfy the last requirement, we must use the DUID to
In order to satisfy the last requirement, we must use the DUID to
identify the DHCPv4 client. So, taking all the requirements identify the DHCPv4 client. So, taking all the requirements
together, the DUID and IAID described in RFC3315 are the only together, the DUID and IAID described in RFC3315 are the only
possible solution. possible solution.
4. Implementation By following these rules, a compliant DHCPv4 client will
interoperate correctly with both compliant and non-complient DHCPv4
servers. A non-compliant DHCPv4 client will also interoperate
correctly with a compliant DHCPv4 server. If either server or
client is not compliant, the goals stated in the draft are not met,
but there is no loss of functionality.
6. Implementation
Here we specify changes to the behavior of DHCPv4 clients and Here we specify changes to the behavior of DHCPv4 clients and
servers. We also specify changes to the wording in RFC2131 and servers. We also specify changes to the wording in RFC2131 and
RFC2132. DHCPv4 clients, servers and relay agents that conform to RFC2132. DHCPv4 clients, servers and relay agents that conform to
this specification must implement RFC2131 and RFC2132 with the this specification must implement RFC2131 and RFC2132 with the
wording changes specified in sections 4.3 and 4.4. wording changes specified in sections 6.3 and 6.4.
4.1. DHCPv4 Client behavior 6.1. DHCPv4 client behavior
DHCPv4 clients conforming to this specification MUST use stable DHCPv4 clients conforming to this specification MUST use stable
DHCPv4 node identifiers in the dhcp-client-identifier option. DHCPv4 node identifiers in the dhcp-client-identifier option.
DHCPv4 clients MUST NOT use client identifiers based solely on DHCPv4 clients MUST NOT use client identifiers based solely on
layer two addresses that are hard-wired to the layer two device layer two addresses that are hard-wired to the layer two device
(e.g., the ethernet MAC address) as suggested in RFC2131, except as (e.g., the ethernet MAC address) as suggested in RFC2131, except as
allowed in section 9.2 of RFC3315. DHCPv4 clients MUST send a allowed in section 9.2 of RFC3315. DHCPv4 clients MUST send a
'client identifier' option containing an Identity Association 'client identifier' option containing an Identity Association
Unique Identifier, as defined in section 10 of RFC3315, and a DHCP Unique Identifier, as defined in section 10 of RFC3315, and a DHCP
Unique Identifier, as defined in section 9 of RFC3315. These Unique Identifier, as defined in section 9 of RFC3315. These
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which is an opaque 32-bit quantity. The IAID is immediately which is an opaque 32-bit quantity. The IAID is immediately
followed by the DUID, which consumes the remaining contents of the followed by the DUID, which consumes the remaining contents of the
'client identifier' option. The format of the 'client identifier' 'client identifier' option. The format of the 'client identifier'
option is as follows: option is as follows:
Code Len Type IAID DUID Code Len Type IAID DUID
+----+----+-----+----+----+----+----+----+----+--- +----+----+-----+----+----+----+----+----+----+---
| 61 | n | 255 | i1 | i2 | i3 | i4 | d1 | d2 |... | 61 | n | 255 | i1 | i2 | i3 | i4 | d1 | d2 |...
+----+----+-----+----+----+----+----+----+----+--- +----+----+-----+----+----+----+----+----+----+---
Any DHCPv4 or DHCPv6 client that conforms to this specification Any DHCPv4 client that conforms to this specification SHOULD
SHOULD provide a means by which an operator can learn what DUID the provide a means by which an operator can learn what DUID the client
client has chosen. Such clients SHOULD also provide a means by has chosen. Such clients SHOULD also provide a means by which the
which the operator can configure the DUID. A device that is operator can configure the DUID. A device that is normally
normally configured with both a DHCPv4 and DHCPv6 client SHOULD configured by both a DHCPv4 and DHCPv6 client SHOULD automatically
automatically use the same DUID for DHCPv4 and DHCPv6 without any use the same DUID for DHCPv4 and DHCPv6 without any operator
operator intervention. intervention.
DHCPv4 clients that support more than one network interface SHOULD DHCPv4 clients that support more than one network interface SHOULD
use the same DUID on every interface. DHCPv4 clients that support use the same DUID on every interface. DHCPv4 clients that support
more than one network interface SHOULD use a different IAID on more than one network interface SHOULD use a different IAID on
each interface. each interface.
4.2. DHCPv4 Server behavior A DHCPv4 client that generates a DUID and that has stable storage
MUST retain this DUID for use in subsequent DHCPv4 messages, even
after an operating system reboot.
6.2 DHCPv6 client behavior
Any DHCPv6 client that conforms to this specification SHOULD
provide a means by which an operator can learn what DUID the client
has chosen. Such clients SHOULD also provide a means by which the
operator can configure the DUID. A device that is normally
configured by both a DHCPv4 and DHCPv6 client SHOULD automatically
use the same DUID for DHCPv4 and DHCPv6 without any operator
intervention.
6.3. DHCPv4 server behavior
This document does not require any change to DHCPv4 or DHCPv6 This document does not require any change to DHCPv4 or DHCPv6
servers that follow RFC2131 and RFC2132. However, some DHCPv4 servers that follow RFC2131 and RFC2132. However, some DHCPv4
servers can be configured not to conform to RFC2131 and RFC2131, in servers can be configured not to conform to RFC2131 and RFC2132, in
the sense that they ignore the 'client identifier' option and use the sense that they ignore the 'client identifier' option and use
the client's hardware address instead. the client's hardware address instead.
DHCPv4 servers that conform to this specification MUST use the DHCPv4 servers that conform to this specification MUST use the
'client identifier' option to identify the client if the client 'client identifier' option to identify the client if the client
sends it. sends it.
DHCPv4 servers MAY use administrator-supplied values for chaddr and DHCPv4 servers MAY use administrator-supplied values for chaddr and
htype to identify the client in the case where the administrator is htype to identify the client in the case where the administrator is
assigning a fixed IP address to the client, even if the client assigning a fixed IP address to the client, even if the client
sends an client identifier option. This is ONLY permitted in the sends an client identifier option. This is ONLY permitted in the
case where the DHCPv4 server administrator has provided the values case where the DHCPv4 server administrator has provided the values
for chaddr and htype, because in this case if it causes a problem, for chaddr and htype, because in this case if it causes a problem,
the administrator can correct the problem by removing the offending the administrator can correct the problem by removing the offending
configuration information. configuration information.
4.3. Changes from RFC2131 6.4. Changes from RFC2131
In section 2 of RFC2131, on page 9, the text that reads "; for In section 2 of RFC2131, on page 9, the text that reads "; for
example, the 'client identifier' may contain a hardware address, example, the 'client identifier' may contain a hardware address,
identical to the contents of the 'chaddr' field, or it may contain identical to the contents of the 'chaddr' field, or it may contain
another type of identifier, such as a DNS name" is deleted. another type of identifier, such as a DNS name" is deleted.
In section 4.2 of RFC2131, the text "The client MAY choose to In section 4.2 of RFC2131, the text "The client MAY choose to
explicitly provide the identifier through the 'client identifier' explicitly provide the identifier through the 'client identifier'
option. If the client supplies a 'client identifier', the client option. If the client supplies a 'client identifier', the client
MUST use the same 'client identifier' in all subsequent messages, MUST use the same 'client identifier' in all subsequent messages,
skipping to change at page 7, line 28 skipping to change at page 8, line 19
Note that these changes do not relieve the DHCPv4 server of the Note that these changes do not relieve the DHCPv4 server of the
obligation to use 'chaddr' as an identifier if the client does not obligation to use 'chaddr' as an identifier if the client does not
send a 'client identifier' option. Rather, they oblige clients send a 'client identifier' option. Rather, they oblige clients
that conform with this document to send a 'client identifier' that conform with this document to send a 'client identifier'
option, and not rely on 'chaddr' for identification. DHCPv4 option, and not rely on 'chaddr' for identification. DHCPv4
servers MUST use 'chaddr' as an identifier in cases where 'client servers MUST use 'chaddr' as an identifier in cases where 'client
identifier' is not sent, in order to support old clients that do identifier' is not sent, in order to support old clients that do
not conform with this document. not conform with this document.
4.4. Changes from RFC2132 6.5. Changes from RFC2132
The text in section 9.14, beginning with "The client identifier MAY The text in section 9.14, beginning with "The client identifier MAY
consist of" through "that meet this requirement for uniqueness." is consist of" through "that meet this requirement for uniqueness." is
replaced with "the client identifier consists of a type field whose replaced with "the client identifier consists of a type field whose
value is normally 255, followed by a four-byte IA_ID field, followed value is normally 255, followed by a four-byte IA_ID field, followed
by the DUID for the client as defined in RF3315, section 9." The by the DUID for the client as defined in RF3315, section 9." The
text "its minimum length is 2" in the following paragraph is deleted. text "its minimum length is 2" in the following paragraph is deleted.
5. Security Considerations 7. Notes on DHCP clients in multi-stage network booting
In some cases a single device may actually run more than one DHCP
client in sequence, in the process of loading an operating system
over the network. In such cases, it may be that the first stage
boot uses a different client identifier, or no client identifier,
than the subsequent stage or stages.
The effect of this, under the DHCPv4 protocol, is that the two (in
some cases more than two!) boot stages will present different
identities. A DHCPv4 server will therefore allocate two different
IP addresses to the two different boot stages.
Some DHCP servers work around this problem for the common case
where the boot PROM presents no client identifier, and the
operating system DHCP client presents a client identifier
constructed from the MAC address of the network interface - both
are treated as the same identifier. This prevents the consumption
of an extra IP address.
A compliant DHCPv4 client does not use a client identifier
constructed from the MAC address of the network interface, because
network interfaces are not stable. So a compliant DHCPv4 client
can't be supported by a simple hack like the one described
previously; this may have some significant impact at some sites.
We can't state the solution to this problem as a set of
requirements, because the circumstances in which this occurs vary
too widely. However, we can make some suggestions.
First, we suggest that DHCP clients in network boot loaders request
short lease times, so that their IP addresses are not retained.
Such clients should send a DHCPRELEASE message to the DHCP server
before moving on to the next stage of the boot process. Such
clients should provide a way for the operating system DHCP client
to configure a DUID to use in subsequent boots. DHCP clients in
the final stage should, where possible, configure the DUID used by
the boot PROM to be the same as the DUID used by the operating
system.
Secondly, implementors of DHCPv4 clients that are expected to only
be used in a multi-stage network boot configuration, and that are
not expected ever to network boot using DHCPv6, and that have a MAC
address that can't be easily changed, may not need to implement the
changes described in this specification. There is some danger in
making this assumption--the first solution suggested is definitely
better. A compromise might be to have the final-stage DHCP client
detect whether it is running on legacy hardware; if it is, it uses
the old identifier; if it is not, it follows the scheme described
in the previous paragraph.
8. Security Considerations
This document raises no new security issues. Potential exposure to This document raises no new security issues. Potential exposure to
attack in the DHCPv4 protocol are discussed in section 7 of the attack in the DHCPv4 protocol are discussed in section 7 of the
DHCP protocol specification [RFC2131] and in Authentication for DHCP protocol specification [RFC2131] and in Authentication for
DHCP messages [RFC3118]. Potential exposure to attack in the DHCP messages [RFC3118]. Potential exposure to attack in the
DHCPv6 protocol is discussed in section 23 of RFC3315. DHCPv6 protocol is discussed in section 23 of RFC3315.
6. IANA Considerations 9. IANA Considerations
This document defines no new name spaces that need to be None.
administered by the IANA. This document deprecates all 'client
identifier' type codes other than 255, and thus there is no need
for the IANA to track additional possible values for the type field
of the 'client identifier' option.
7. Normative References 10. Normative References
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131,
March 1997. March 1997.
[RFC2132] S. Alexander, R. Droms, "DHCP Options and BOOTP Vendor [RFC2132] S. Alexander, R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC2132, March, 1997 Extensions", RFC2132, March, 1997
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
Carney, M., "Dynamic Host Configuration Protocol for Carney, M., "Dynamic Host Configuration Protocol for
IPv6 (DHCPV6)", July, 2003 IPv6 (DHCPV6)", July, 2003
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8. Informative References 11. Informative References
[RFC3118] Droms, R., Arbaugh, W., "Authentication for DHCP [RFC3118] Droms, R., Arbaugh, W., "Authentication for DHCP
Messages", RFC3118, June, 2001 Messages", RFC3118, June, 2001
Author's Addresses Author's Addresses
Ted Lemon Ted Lemon
Nominum Nominum
2385 Bay Road 2385 Bay Road
Redwood City, CA 94063 USA Redwood City, CA 94063 USA
skipping to change at page 8, line 38 skipping to change at page 10, line 28
Bill Sommerfeld Bill Sommerfeld
Sun Microsystems Sun Microsystems
1 Network Drive 1 Network Drive
Burlington, MA 01824 Burlington, MA 01824
+1 781 442 3458 +1 781 442 3458
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