Cisco Systems (India) Private Limited
October 2004
Network Information Service (NIS)
Configuration Options for
Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
Status of this Memo
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This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
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Copyright © The Internet Society (2004).
Abstract
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This document describes four options for Network Information Service (NIS) related configuration information in Dynamic Host Configuration Protocol for IPv6 (DHCPv6): NIS Servers, NIS+ Servers, NIS Client Domain Name, NIS+ Client Domain name.
1. Introduction
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This document describes four options for passing configuration information related to Network Information Service (NIS) [3] in DHCPv6 (RFC 3315 [1]).
The options defined in this document can only be used to configure information about NIS servers that can be reached using IPv6. The DHCP option to configure information about IPv4 NIS servers can be found in RFC 2132 [4]. Mechanisms for configuring IPv4/IPv6 dual- stack applications are being considered, but are not specified in this document.
2. Terminology
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The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL in this document are to be interpreted as described in BCP 14, RFC 2119 [2].
Throughout this document, unless otherwise specified, the acronym DHCP refers to DHCP as specified in RFC 3315.
This document uses terminology specific to IPv6 and DHCP as defined in section "Terminology" of RFC 3315.
3. Network Information Service (NIS) Servers Option
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The Network Information Service (NIS) Servers option provides a list of one or more IPv6 addresses of NIS servers available to the client. Clients MUST treat the list of NIS servers as an ordered list. The server MAY list the NIS servers in the order of preference.
The format of the Network Information Service Servers option is as shown below:
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_NIS_SERVERS | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | NIS server (IPv6 address) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | NIS server (IPv6 address) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code: OPTION_NIS_SERVERS (27) option-len: Length of the 'NIS server' fields in octets; It must be a multiple of 16 NIS server: IPv6 address of NIS server
4. Network Information Service V2 (NIS+) Servers Option
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The Network Information Service V2 (NIS+) Servers option provides a list of one or more IPv6 addresses of NIS+ servers available to the client. Clients MUST treat the list of NIS+ servers as an ordered list. The server MAY list the NIS+ servers in the order of preference.
The format of the Network Information Service V2 (NIS+) Servers option is as shown below:
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_NISP_SERVERS | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | NIS+ server (IPv6 address) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | NIS+ server (IPv6 address) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+option-code:
OPTION_NISP_SERVERS (28) option-len: Length of the 'NIS+ server' fields in octets; It must be a multiple of 16 NIS+ server: IPv6 address of NIS+ server
5. Network Information Service (NIS) Domain Name Option
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The Network Information Service (NIS) Domain Name option is used by the server to convey client's NIS Domain Name info to the client.
The format of the NIS Domain Name option is as shown below:
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_NIS_DOMAIN_NAME | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | nis-domain-name | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code: OPTION_NIS_DOMAIN_NAME (29) option-len: Length of the 'nis-domain-name' field in octets nis-domain-name: NIS Domain name for clientThe 'nis-domain-name' MUST be encoded as specified in section "Representation and Use of domain names" of the DHCPv6 specification [1].
6. Network Information Service V2 (NIS+) Domain Name Option
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The Network Information Service V2 (NIS+) Domain Name option is used by the server to convey client's NIS+ Domain Name info to the client.
The format of the NIS+ Domain Name option is as shown below:
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_NISP_DOMAIN_NAME | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | nisp-domain-name | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code: OPTION_NISP_DOMAIN_NAME (30) option-len: Length of the 'nisp-domain-name' field in octets nisp-domain-name: NIS+ Domain name for clientThe 'nisp-domain-name' MUST be encoded as specified in section "Representation and Use of domain names" of the DHCPv6 specification [1].
7. Appearance of these Options
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The NIS servers, NIS+ servers, NIS domain name and NIS+ domain name options MUST NOT appear in other than the following messages: Solicit, Advertise, Request, Renew, Rebind, Information-Request and Reply.
The option number for these options MAY appear in the Option Request Option [1] in the following messages: Solicit, Request, Renew, Rebind, Information-Request and Reconfigure.
8. Security Considerations
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The NIS servers, NIS+ servers, NIS domain name and NIS+ domain name options may be used by an intruder DHCPv6 server to assign invalid NIS parameters, resulting in clients unable to use NIS service.
The NIS servers and NIS+ servers options may be used by an intruder DHCPv6 server to cause the DHCPv6 clients to send their queries to an intruder NIS/NIS+ server. This misdirected searches may be used to spoof NIS/NIS+ names.
The NIS domain name and NIS+ domain name options may be used by an intruder DHCPv6 server to cause the DHCPv6 clients to search through invalid domains for incompletely specified domain names. The results of these misdirected searches may be used to spoof NIS/NIS+ names.
To avoid attacks through these options, the DHCPv6 client SHOULD use authenticated DHCP (see section "Authentication of DHCP messages" in the DHCPv6 specification [1]).
9. IANA Considerations
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The IANA has assigned option codes to the following options from the option-code space defined in "DHCPv6 Options" section of the DHCPv6 specification [1].
Option Name Value Described in OPTION_NIS_SERVERS 27 Section 3 OPTION_NISP_SERVERS 28 Section 4 OPTION_NIS_DOMAIN_NAME 29 Section 5 OPTION_NISP_DOMAIN_NAME 30 Section 6
10. References
10.1. Normative References
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[1] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
10.2. Informative References
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[3] Sun Microsystems, "System and Network Administration", March 1990. [4] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997.
Acknowledgements
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Thanks to the DHC Working Group for their time and input into the specification. In particular, thanks to (in alphabetical order) Bernie Volz, Jim Bound, Margaret Wasserman, Pekka Savola, Ralph Droms, and Thomas Narten for their thorough review.
Author's Address
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Vijayabhaskar A Kalusivalingam
Cisco Systems (India) Private Limited,
No: 9, Brunton Road,
Bangalore - 560025
IndiaPhone: +91-80-51036615 EMail: vibhaska@cisco.com
Full Copyright Statement
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Copyright © The Internet Society (2004).
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Acknowledgement
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Funding for the RFC Editor function is currently provided by the Internet Society.