Registering Self-generated IPv6 Addresses using DHCPv6
draft-wkumari-dhc-addr-notification-02
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
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|
|---|---|---|---|
| Authors | Warren "Ace" Kumari , Suresh Krishnan , Sheng Jiang , Rajiv Asati , Lorenzo Colitti | ||
| Last updated | 2022-07-28 | ||
| Replaced by | draft-ietf-dhc-addr-notification | ||
| RFC stream | (None) | ||
| Formats | |||
| Reviews |
DNSDIR Early review
(of
-07)
by Jim Reid
Almost ready
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| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
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| IESG | IESG state | I-D Exists | |
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draft-wkumari-dhc-addr-notification-02
Dynamic Host Configuration W. Kumari
Internet-Draft Google, LLC
Intended status: Experimental S. Krishnan
Expires: 29 January 2023 Kaloom
S. Jiang
R. Asati
Cisco Systems, Inc.
L. Colitti
Google
28 July 2022
Registering Self-generated IPv6 Addresses using DHCPv6
draft-wkumari-dhc-addr-notification-02
Abstract
This document defines a method to inform a DHCPv6 server that a
device has a self-generated or statically configured address.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://wkumari.github.io/draft-wkumari-dhc-addr-notification/draft-
wkumari-dhc-addr-notification.html. Status information for this
document may be found at https://datatracker.ietf.org/doc/draft-
wkumari-dhc-addr-notification/.
Discussion of this document takes place on the Dynamic Host
Configuration Working Group mailing list (mailto:dhcwg@ietf.org),
which is archived at https://mailarchive.ietf.org/arch/browse/dhcwg/.
Source for this draft and an issue tracker can be found at
https://github.com/wkumari/draft-wkumari-dhc-addr-notification.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on 29 January 2023.
Copyright Notice
Copyright (c) 2022 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
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Description of Mechanism . . . . . . . . . . . . . . . . . . 3
4. DHCPv6 ADDR-REG-NOTIFICATION Message . . . . . . . . . . . . 4
5. DHCPv6 Address Registration Procedure . . . . . . . . . . . . 5
5.1. DHCPv6 Address Registration Request . . . . . . . . . . . 5
5.2. Registration Expiry and Refresh . . . . . . . . . . . . . 6
5.3. Retransmission . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7.1. Value Description Reference . . . . . . . . . . . . . . . 7
7.2. Code Name Reference . . . . . . . . . . . . . . . . . . . 8
8. Normative References . . . . . . . . . . . . . . . . . . . . 8
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 8
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
It is very common operational practice, especially in enterprise
networks, to use IPv4 DHCP logs for troubleshooting or security
purposes. Examples of this include a helpdesk dealing with a ticket
such as "The CEO's laptop cannot connect to the printer"; if the MAC
address of the printer is known (for example from an inventory
system), the IPv4 address can be retrieved from the DHCP logs and the
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printer pinged to determine if it is reachable. Another common
example is a Security Operations team discovering suspicious events
in outbound firewall logs and then consulting DHCP logs to determine
which employee's laptop had that IPv4 address at that time so that
they can quarantine it and remove the malware.
This operational practice relies on the DHCP server knowing the IP
address assignments. Therefore, the practice does not work if static
IP addresses are manually configured on devices or self-assigned
addresses (such as when self-configuring an IPv6 address using SLAAC
[RFC4862]) are used.
The lack of this parity with IPv4 is one of the reasons that some
enterprise networks are unwilling to deploy IPv6.
This document provides a mechanism for a device to inform the DHCPv6
server that it has a self-configured IPv6 address (or has a
statically configured address), and thus provides parity with IPv4 in
this aspect.
This document borrows heavily from a previous document, draft-ietf-
dhc-addr-registration, which defined "a mechanism to register self-
generated and statically configured addresses in DNS through a DHCPv6
server".
2. Conventions and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Description of Mechanism
After successfully assigning a self-generated IPv6 address on one of
its interfaces, an end-host implementing this specification SHOULD
multicast an ADDR-REG-NOTIFICATION message. After receiving the
address registration request, the DHCPv6 server MAY record and log
the IPv6 address.
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+----+ +----------------+ +---------------+
|Host| |First-hop router| |Addr-Reg Server|
+----+ +----------------+ +---------------+
| SLAAC | |
|<--------->| |
| | |
| | ADDR-REG-NOTIFICATION |
|------------------------------------------------->|
| | |Register / log
| | |address
Figure 1: Address Registration Procedure
4. DHCPv6 ADDR-REG-NOTIFICATION Message
The DHCPv6 client sends an ADDR-REG-NOTIFICATION message to inform
that an IPv6 address is in use. The format of the ADDR-REG-
NOTIFICATION message is described as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-type | transaction-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. options .
. (variable) .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
msg-type Identifies the DHCPv6 message type;
Set to ADDR-REG-NOTIFICATION (TBA1).
transaction-id The transaction ID for this message exchange.
options Options carried in this message.
Figure 2: DHCPv6 ADDR-REG-NOTIFICATION message
The ADDR-REG-NOTIFICATION message MUST NOT contain server-identifier
option and MUST contain the IA Address option. The ADDR-REG-
NOTIFICATION message is dedicated for clients to initiate an address
registration request toward an address registration server.
Consequently, clients MUST NOT put any Option Request Option(s) in
the ADDR-REG-NOTIFICATION message. Clients MAY include other
options, such as the Client FQDN Option [RFC4704].
Clients MUST discard any received ADDR-REG-NOTIFICATION messages.
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Servers MUST discard any ADDR-REG-NOTIFICATION messages that meet any
of the following conditions:
* the message does not include a Client Identifier option;
* the message includes a Server Identifier option;
* the message does not include at least one IA Address option;
* the message includes an Option Request Option.
5. DHCPv6 Address Registration Procedure
The DHCPv6 protocol is used as the address registration protocol when
a DHCPv6 server performs the role of an address registration server.
The DHCPv6 IA Address option [RFC8415] is adopted in order to fulfill
the address registration interactions.
5.1. DHCPv6 Address Registration Request
The end-host sends a DHCPv6 ADDR-REG-NOTIFICATION message to the
address registration server to the All_DHCP_Relay_Agents_and_Servers
multicast address (ff02::1:2). The host SHOULD send the packet from
the address being registered.
The end-host MUST include a Client Identifier option and at least one
IA Address option in the ADDR-REG-NOTIFICATION message. The host
SHOULD send separate messages for each address (so each message
include only one IA Address option) but MAY send a single packet
containing multiple options.
The host MUST only send the ADDR-REG-NOTIFICATION message for valid
([RFC4862]) addresses of global scope ([RFC4007]).
The host MUST NOT send the ADDR-REG-NOTIFICATION message if it has
not received any Router Advertisement message with either M or O
flags set to 1.
{TODO (WK): DHCPv6 uses "DHCP Unique Identifier (DUID)" to identify
clients. This doesn't really meet our design goal of "what IP does
the printer have?!". One of the DUID types is "DUID Based on Link-
layer Address (DUID-LL)", but this is "any one network interface(s)"
- this is probably good enough for the inventory use case, but still
not ideal}
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After receiving this ADDR-REG-NOTIFICATION message, the address
registration server MUST register the binding between the provided
Client Identifier and IPv6 address. If the DHCPv6 server does not
support the address registration function, it MUST drop the message
(and may log the event).
5.2. Registration Expiry and Refresh
For every successful binding registration, the address registration
server MUST record the Client-Identifier-to-IPv6-address bindings and
associated valid-lifetimes in its storage, and SHOULD log this
information in a manner similar to if it had performed the
assignment.
If an ADDR-REG-NOTIFICATION message updates the existing Client-
Identifier-to-IPv6-address binding the server MUST log the event.
The address registration client MUST refresh the registration before
it expires (i.e. before the preferred lifetime of the IA address
elapses) by sending a new ADDR-REG-NOTIFICATION to the address
registration server. If the address registration server does not
receive such a refresh after the preferred lifetime has passed, it
SHOULD remove the record of the Client-Identifier-to-IPv6-address
binding.
It is RECOMMENDED that clients initiate a refresh at about 85% of the
preferred lifetime. Because RAs may periodically 'reset' the
preferred-lifetime, the refresh timer MUST be independently
maintained from the address valid-lifetime. Clients SHOULD set a
refresh timer to 85% of the preferred lifetime when they complete a
registration operation and only update this timer if 85% of any
updated preferred lifetime would be sooner than the timer.
{TODO: See Issue #3 regarding the appropriate timers, and provide
better guidance. We could do some complex "min (4h, max
(router_lifetime, preferred_lifetime))" calculation, but that's a bit
of a pain and leads to bikeshedding. I suspect that just using a
static number would be better.}
{TODO: Add some text around "feel free to ignore messages if it looks
like a DoS attack" / your leases table is getting full. Note that
this is an existing issue for DHCP and spoofed MACs (ask me how I
know :-)) }
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5.3. Retransmission
To reduce the effects of packet loss on registration, the client
SHOULD retransmit initial registrations. Registrations should be
retransmitted according to the Retrans Timer specified by the Router
Advertisement on the link. Retries should be jittered to prevent
overloading the DHCP infrastructure when a new prefix is announced to
the link via Router Advertisement.
The client MUST refresh the registration when 1/3 of the Preferred
Lifetime of the address has elapsed. Such retransmissions should be
jittered.
6. Security Considerations
An attacker may attempt to register a large number of addresses in
quick succession in order to overwhelm the address registration
server and / or fill up log files. These attacks may be mitigated by
using generic DHCPv6 protection such as the AUTH option [RFC8415].
One of the primary use-cases for the mechanism described in this
document is to identify which device is infected with malware (or is
otherwise doing bad things) so that it can be blocked from accessing
the network. As the device itself is responsible for informing the
DHCPv6 server that it is using an address, malware (or a malicious
client) can simply not send the ADDR-REG-NOTIFICATION message. This
is an informational, optional mechanism, and is designed to aid in
debugging. It is not intended to be a strong security access
mechanism.
7. IANA Considerations
This document defines a new DHCPv6 message, the ADDR-REG-NOTIFICATION
message (TBA1) described in Section 4, that requires an allocation
out of the registry of Message Types defined at
http://www.iana.org/assignments/dhcpv6-parameters/
7.1. Value Description Reference
TBA1 ADDR-REG-NOTIFICATION this document
This document defines a new DHCPv6 Status code, the
RegistrationDenied (TBA2) described in Section 5, that requires an
allocation out of the registry of Status Codes defined at
http://www.iana.org/assignments/dhcpv6-parameters/
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7.2. Code Name Reference
TBA2 RegistrationDenied this document
8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and
B. Zill, "IPv6 Scoped Address Architecture", RFC 4007,
DOI 10.17487/RFC4007, March 2005,
<https://www.rfc-editor.org/rfc/rfc4007>.
[RFC4704] Volz, B., "The Dynamic Host Configuration Protocol for
IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN)
Option", RFC 4704, DOI 10.17487/RFC4704, October 2006,
<https://www.rfc-editor.org/rfc/rfc4704>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/rfc/rfc4862>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A.,
Richardson, M., Jiang, S., Lemon, T., and T. Winters,
"Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 8415, DOI 10.17487/RFC8415, November 2018,
<https://www.rfc-editor.org/rfc/rfc8415>.
Acknowledgments
"We've Been Trying To Reach You About Your Car's Extended Warranty"
Much thanks to Jen Linkova for additional text on client behavior.
Also, much thanks to Erik Kline and Lorenzo Colitti for significant
discussion and feedback.
Contributors
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Gang Chen
China Mobile
53A, Xibianmennei Ave.
Xuanwu District
Beijing
P.R. China
Email: phdgang@gmail.com
Authors' Addresses
Warren Kumari
Google, LLC
Email: warren@kumari.net
Suresh Krishnan
Kaloom
Email: suresh@kaloom.com
Sheng Jiang
Beijing
P.R. China
Email: jiangsheng@gmail.com
Rajiv Asati
Cisco Systems, Inc.
7025 Kit Creek road
Research Triangle Park, 27709-4987
United States of America
Email: rajiva@cisco.com
Lorenzo Colitti
Google
Shibuya 3-21-3,
Japan
Email: lorenzo@google.com
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