Network Working Group V. Kalusivalingam

Network Working Group V. Kalusivalingam
Request for Comments: 3898 Cisco Systems (India) Private Limited
Category: Standards Track October 2004

Network Information Service (NIS)
Configuration Options for
Dynamic Host Configuration Protocol for IPv6 (DHCPv6)

Status of this Memo

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

Copyright (C) The Internet Society (2004).

Abstract

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

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

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].

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RFC 3898 NIS Configuration Options for DHCPv6 October 2004

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

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

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.

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RFC 3898 NIS Configuration Options for DHCPv6 October 2004

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

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

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RFC 3898 NIS Configuration Options for DHCPv6 October 2004

nis-domain-name: NIS Domain name for client

The '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

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 client

The '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

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

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.

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RFC 3898 NIS Configuration Options for DHCPv6 October 2004

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

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

[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

[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.

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RFC 3898 NIS Configuration Options for DHCPv6 October 2004

Acknowledgements

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

Vijayabhaskar A Kalusivalingam
Cisco Systems (India) Private Limited,
No: 9, Brunton Road,
Bangalore - 560025
India

Phone: +91-80-51036615
EMail: [email protected]

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RFC 3898 NIS Configuration Options for DHCPv6 October 2004

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