draft-ietf-ntp-dhcpv6-ntp-opt-04.txt   draft-ietf-ntp-dhcpv6-ntp-opt-05.txt 
Network Working Group R. Gayraud Network Working Group R. Gayraud
Internet-Draft None Internet-Draft None
Obsoletes: RFC 4075 B. Lourdelet Intended status: Standards Track B. Lourdelet
(if approved) Cisco Systems, Inc. Expires: April 5, 2010 Cisco Systems, Inc.
Intended status: Standards Track July 28, 2009 October 2, 2009
Expires: January 29, 2010
Network Time Protocol (NTP) Server Option for DHCPv6 Network Time Protocol (NTP) Server Option for DHCPv6
draft-ietf-ntp-dhcpv6-ntp-opt-04.txt draft-ietf-ntp-dhcpv6-ntp-opt-05.txt
Status of this Memo Status of this Memo
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skipping to change at page 1, line 44 skipping to change at page 1, line 43
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Copyright Notice Copyright Notice
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Abstract Abstract
The NTP Server Option for DHCPv6 provides NTP (Network Time Protocol The NTP Server Option for Dynamic Host Configuration Protocol for
version 4) configuration information to DHCPv6 hosts. IPv6 (DHCPv6) provides NTP (Network Time Protocol version 4) Server
location information to DHCPv6 hosts.
Table of Contents Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements notation . . . . . . . . . . . . . . . . . . . . . 3
2.1. Related Work and Usage Model . . . . . . . . . . . . . . . 3 3. Related Work and Usage Model . . . . . . . . . . . . . . . . . 3
3. NTP Server Option for DHCPv6 . . . . . . . . . . . . . . . . . 3 4. NTP Server Option for DHCPv6 . . . . . . . . . . . . . . . . . 3
3.1. NTP Server Address Suboption . . . . . . . . . . . . . . . 5 4.1. NTP Server Address Suboption . . . . . . . . . . . . . . . 5
3.2. NTP Multicast Address Suboption . . . . . . . . . . . . . . 5 4.2. NTP Multicast Address Suboption . . . . . . . . . . . . . . 5
3.3. NTP Server FQDN Suboption . . . . . . . . . . . . . . . . . 6 4.3. NTP Server FQDN Suboption . . . . . . . . . . . . . . . . . 6
4. Examples of use . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Appearance of this Option . . . . . . . . . . . . . . . . . . . 6
5. Appearance of this Option . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 7. RFC 4075 Deprecation . . . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . . 8 9.1. Normative References . . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Requirements notation 1. Introduction
This document defines a DHCPv6 option and associated suboptions to
provide Network Time Protocol version 4 [draft-ntpv4] or greater
Server location information to DHCPv6 hosts.
2. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Introduction 3. Related Work and Usage Model
This document defines a DHCPv6 option and associated suboptions to
provide Network Time Protocol version 4 [draft-ntpv4] or greater
configuration information to DHCPv6 hosts.
2.1. Related Work and Usage Model
The NTP service is publicly offered on the Internet by a number of The NTP service is publicly offered on the Internet by a number of
organizations. Those servers can be used but not abused, so any organizations. Those Servers can be used but not abused, so any
method which is tasked to disseminate locations of NTP Servers must method which is tasked to disseminate locations of NTP Servers must
act responsibly in a manner that does not lead to public server act responsibly in a manner that does not lead to public Server
overloading. When using DHCPv6 to offer NTP Server location, and if overloading. When using DHCPv6 to offer NTP Server location, and if
there is a need to distribute a device with a hardcoded there is a need to distribute a host with a hardcoded configuration,
configuration, this configuration MUST NOT include server location this configuration MUST NOT include Server location that is not part
that is not part of the organization that distribute this device. of the organization that distributes this device. Typical usage of
Typical usage of this option is to specify an NTP Server that is part this option is to specify an NTP Server that is part of the
of the organization that operates the DHCPv6 server. organization that operates the DHCPv6 Server.
The location of the NTP service, like any other Internet service, can The location of the NTP service, like any other Internet service, can
be specified by an IP address or an FQDN. By design, DHCP offers be specified by an IP address or a Fully Qualified Domain Name
information to multiple devices and is prone to amplification of (FQDN). By design, DHCP offers information to multiple devices and
mistakes, so great care must be taken to define its configuration. is prone to amplification of mistakes, so great care must be taken to
Specification of the NTP service by FQDN offers a level of define its configuration. Specification of the NTP service by FQDN
indirection that works as a possible mitigation tool in case of offers a level of indirection that works as a possible mitigation
misconfiguration. DNS can be used to redirect misconfigured clients tool in case of misconfiguration. DNS can be used to redirect
to an unexisting IPv6 address instead of having to change the address misconfigured clients to an IPv6 address that is not configured on
of the NTP server itself. any host instead of having to change the address of the NTP Server
itself.
While the NTP specification defines a comprehensive set of While the NTP specification defines a comprehensive set of
configuration parameters, modification of those parameters is best configuration parameters, modification of those parameters is best
left to the decision of the client itself. The DHCPv6 option for NTP left to the decision of the client itself. The DHCPv6 option for NTP
is then restricted to server location. is therefore restricted to Server location.
3. NTP Server Option for DHCPv6 4. NTP Server Option for DHCPv6
This option serves as a container for all the information related to This option serves as a container for Server location information
one NTP server or SNTP server. This option can appear multiple times related to one NTP Server or Simple Network Time Protocol (SNTP)
in a DHCPv6 message. Each instance of this option is to be
considered by the NTP client or SNTP client as a server to include in [RFC4330] Server. This option can appear multiple times in a DHCPv6
its configuration. message. Each instance of this option is to be considered by the NTP
client or SNTP client as a Server to include in its configuration.
The option itself does not contain any value. Instead, it contains The option itself does not contain any value. Instead, it contains
one or several suboptions that carry NTP server or SNTP server one or several suboptions that carry NTP Server or SNTP Server Server
configuration information. This option MUST include one, and only location. This option MUST include one, and only one, time source
one, time source suboption. The currently defined time source suboption. The currently defined time source suboptions are:
suboptions are: NTP_OPTION_SRV_ADDR, NTP_OPTION_SRV_MC_ADDR, NTP_OPTION_SRV_ADDR, NTP_OPTION_SRV_MC_ADDR, NTP_OPTION_SRV_FQDN. It
NTP_OPTION_SRV_FQDN. It carries the NTP server or SNTP server carries the NTP Server or SNTP Server location, as a unicast or
location, as a unicast or multicast IPv6 address or as an NTP server multicast IPv6 address or as an NTP Server or SNTP Server FQDN. More
or SNTP server FQDN. More time source suboptions may be defined in time source suboptions may be defined in the future. While the FQDN
the future. While the FQDN option offers the most deployment option offers the most deployment flexibility, resiliency as well as
flexibility, resiliency as well as security, the IP address options security, the IP address options are defined to cover cases where a
are defined to cover cases where a dependancy to DNS is not DNS dependancy is not desirable.
desirable.
If the NTP server or SNTP server location is an IPv6 multicast If the NTP Server or SNTP Server location is an IPv6 multicast
address, the client SHOULD use this address as an NTP multicast group address, the client SHOULD use this address as an NTP multicast group
address and listen to messages sent to this group in order to address and listen to messages sent to this group in order to
synchronize its clock. synchronize its clock.
The format of the NTP Server Option is: The format of the NTP Server Option is:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_NTP_SERVER | option-len | | OPTION_NTP_SERVER | option-len |
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: : : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| suboption-n | | suboption-n |
: : : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_NTP_SERVER (TBD_IANA), option-code: OPTION_NTP_SERVER (TBD_IANA),
option-len: Total length of the included suboptions. option-len: Total length of the included suboptions.
This document does not define any priority between the client's This document does not define any priority relationship between the
embedded configuration and the NTP servers or SNTP servers discovered client's embedded configuration (if any) and the NTP or SNTP Servers
via this option. In particular, the client is allowed to discovered via this option. In particular, the client is allowed to
simultaneously use its own configured NTP servers or SNTP servers and simultaneously use its own configured NTP Servers or SNTP Servers and
the servers discovered via DHCP. the Servers discovered via DHCP.
3.1. NTP Server Address Suboption 4.1. NTP Server Address Suboption
This suboption is intended to appear inside the OPTION_NTP_SERVER This suboption is intended to appear inside the OPTION_NTP_SERVER
option. It specifies the IPv6 unicast address of an NTP server or option. It specifies the IPv6 unicast address of an NTP Server or
SNTP server available to the client. An example of use is present in SNTP Server available to the client.
Section 4.
The format of the NTP Server Address Suboption is: The format of the NTP Server Address Suboption is:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NTP_SUBOPTION_SRV_ADDR | suboption-len = 16 | | NTP_SUBOPTION_SRV_ADDR | suboption-len = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| | | |
| IPv6 address of NTP server | | IPv6 address of NTP Server |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
suboption-code: NTP_SUBOPTION_SRV_ADDR (1), suboption-code: NTP_SUBOPTION_SRV_ADDR (1),
suboption-len: 16. suboption-len: 16.
3.2. NTP Multicast Address Suboption 4.2. NTP Multicast Address Suboption
This suboption is intended to appear inside the OPTION_NTP_SERVER This suboption is intended to appear inside the OPTION_NTP_SERVER
option. It specifies the IPv6 address of the IPv6 multicast group option. It specifies the IPv6 address of the IPv6 multicast group
address used by NTP on the local network. An example of use is address used by NTP on the local network.
present in Section 4.
The format of the NTP Multicast Address Suboption is: The format of the NTP Multicast Address Suboption is:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NTP_SUBOPTION_MC_ADDR | suboption-len = 16 | | NTP_SUBOPTION_MC_ADDR | suboption-len = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| | | |
| Multicast IPv6 address | | Multicast IPv6 address |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
suboption-code: NTP_SUBOPTION_MC_ADDR (2), suboption-code: NTP_SUBOPTION_MC_ADDR (2),
suboption-len: 16. suboption-len: 16.
3.3. NTP Server FQDN Suboption 4.3. NTP Server FQDN Suboption
This suboption is intended to appear inside the OPTION_NTP_SERVER This suboption is intended to appear inside the OPTION_NTP_SERVER
option. It specifies the FQDN of an NTP server or SNTP server option. It specifies the FQDN of an NTP Server or SNTP Server
available to the client. available to the client.
The format of the NTP Server FQDN Suboption is: The format of the NTP Server FQDN Suboption is:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NTP_SUBOPTION_SRV_FQDN | suboption-len | | NTP_SUBOPTION_SRV_FQDN | suboption-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| FQDN of NTP server | | FQDN of NTP Server |
: : : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
suboption-code: NTP_SUBOPTION_SRV_FQDN (3), suboption-code: NTP_SUBOPTION_SRV_FQDN (3),
suboption-len: Length of the included FQDN field, suboption-len: Length of the included FQDN field,
FQDN: Fully Qualified Domain Name of the NTP server or SNTP server. FQDN: Fully Qualified Domain Name of the NTP Server or SNTP Server.
This field MUST be encoded as described in [RFC3315], This field MUST be encoded as described in [RFC3315],
section 8. section 8.
4. Examples of use
To instruct a client to use an NTP server or SNTP server located at
address 2001:db8::1, a DHCP server shall use the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_NTP_SERVER | option-len = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NTP_SUBOPTION_SRV_ADDR | suboption-len = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 address = 2001:db8::1 |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
To to enable a client to use the 'ntp.example.com' server, a DHCP
server shall use the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_NTP_SERVER | option-len = 21 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NTP_SUBOPTION_SRV_FQDN | suboption-len = 17 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 3 | 'n' | 't' | 'p' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 7 | 'e' | 'x' | 'a' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 'm' | 'p' | 'l' | 'e' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 3 | 'c' | 'o' | 'm' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0 |
+-+-+-+-+-+-+-+-+
To instruct a client to join the FF05::101 NTP multicast group, a
DHCP server shall use the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_NTP_SERVER | option-len = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NTP_SUBOPTION_MC_ADDR | suboption-len = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 address = FF05::101 |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5. Appearance of this Option 5. Appearance of this Option
The OPTION_NTP_SERVER option can appear multiple times in a DHCPv6 The OPTION_NTP_SERVER option can appear multiple times in a DHCPv6
message. The order in which these options appear is not significant. message. The order in which these options appear is not significant.
The client uses its usual algorithms to determine which server(s) or The client uses its usual algorithms to determine which Server(s) or
multicast group(s) should be prefered to synchronize its clock. multicast group(s) should be prefered to synchronize its clock.
The OPTION_NTP_SERVER option MUST NOT appear in messages other than The OPTION_NTP_SERVER option MUST NOT appear in messages other than
the following: Solicit, Advertise, Request, Renew, Rebind, the following: Solicit, Advertise, Request, Renew, Rebind,
Information-Request, and Reply. If this option appears in messages Information-Request, and Reply. If this option appears in messages
other than those specified above, the receiver MUST ignore it. other than those specified above, the receiver MUST ignore it.
The option number for this option MAY appear in the "Option Request" The option number for this option MAY appear in the "Option Request"
option [RFC3315] in the following messages: Solicit, Request, Renew, option [RFC3315] in the following messages: Solicit, Request, Renew,
Rebind, Information-Request, and Reconfigure. If this option number Rebind, Information-Request, and Reconfigure. If this option number
appears in the "Option Request" option in messages other than those appears in the "Option Request" option in messages other than those
specified above, the receiver SHOULD ignore it. specified above, the receiver SHOULD ignore it.
6. Security Considerations 6. Security Considerations
This option could be used by an intruder to advertise the address of This option could be used by an intruder to advertise the address of
a malicious NTP server or SNTP server and adversely affect the clock a malicious NTP Server or SNTP Server and adversely affect the clock
of clients on the network. The consequences of such an attack can be of clients on the network. The consequences of such an attack can be
critical, because many security protocols depend on time critical, because many security protocols depend on time
synchronization to run their algorithms. As an example, an attacker synchronization to run their algorithms. As an example, an attacker
could break connectivity between SEND-enabled nodes [RFC3971], simply could break connectivity between SEND-enabled nodes [RFC3971], simply
by affecting the clock on these nodes. by affecting the clock on these nodes.
To prevent these attacks, it is strongly advisable to secure the use To prevent these attacks, it is strongly advisable to secure the use
of this option either by: of this option either by:
- using the NTPv4 Autokey public key authentication, as defined - using the NTPv4 Autokey public key authentication, as defined
in [draft-autokey] or, in [draft-autokey] or,
- using authenticated DHCP as described in [RFC3315] section 21. - using authenticated DHCP as described in [RFC3315] section 21.
7. IANA Considerations 7. RFC 4075 Deprecation
[RFC4075] (SNTP Configuration Option for DHCPv6) provides some degree
of automatic time Server configuration for IPv6, as it specifies how
to transmit SNTP [RFC4330] Servers addresses through DHCPv6. However
this approach is not suitable for all NTP deployments. It is not an
extensible mechanism and introduces some semantic confusion throught
the use of the "SNTP" acronym. Additionally the approach of only
offering IPv6 addresses to specify Server location does not meet NTP
requirements that make use of a FQDN (Fully Qualified Domain Name) as
well. For all the abovementioned reasons, this document makes
[RFC4075] deprecated.
8. IANA Considerations
When this document is published, the IANA is requested to assign an When this document is published, the IANA is requested to assign an
option code from the "DHCPv6 Options Codes" registry for option code from the "DHCPv6 Options Codes" registry for
OPTION_NTP_SERVER. OPTION_NTP_SERVER.
8. References 9. References
8.1. Normative References 9.1. Normative References
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003. IPv6 (DHCPv6)", RFC 3315, July 2003.
[draft-ntpv4] [draft-ntpv4]
Burbank, J., Kasch, W., Martin, J., and D. Mills, "Network Burbank, J., Kasch, W., Martin, J., and D. Mills, "Network
Time Protocol Version 4 Protocol And Algorithms Time Protocol Version 4 Protocol And Algorithms
Specification", draft-ietf-ntp-ntpv4-proto-11 (work in Specification", draft-ietf-ntp-ntpv4-proto-11 (work in
progress), September 2008. progress), September 2008.
[draft-autokey] [draft-autokey]
Haberman, B. and D. Mills, "Network Time Protocol Version Haberman, B. and D. Mills, "Network Time Protocol Version
4 Autokey Specification", draft-ietf-ntp-autokey-04 (work 4 Autokey Specification", draft-ietf-ntp-autokey-06 (work
in progress), August 2008. in progress), July 2009.
8.2. Informative References 9.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure [RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
Neighbor Discovery (SEND)", RFC 3971, March 2005. Neighbor Discovery (SEND)", RFC 3971, March 2005.
[RFC4075] Kalusivalingam, V., "Simple Network Time Protocol (SNTP) [RFC4075] Kalusivalingam, V., "Simple Network Time Protocol (SNTP)
Configuration Option for DHCPv6", RFC 4075, May 2005. Configuration Option for DHCPv6", RFC 4075, May 2005.
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