draft-ietf-dhc-dhcpv6-opt-dnsconfig-00.txt   draft-ietf-dhc-dhcpv6-opt-dnsconfig-01.txt 
Network Working Group J. Bound Network Working Group R. Droms (ed.)
Internet-Draft Compaq Computer Corporation Internet-Draft Cisco Systems
Expires: July 2, 2002 M. Carney Expires: September 30, 2002 Apr 2002
Sun Microsystems, Inc.
C. Perkins
Nokia Research Center
T. Lemon
Nominum
B. Volz
Ericsson
R. Droms
Cisco Systems
Jan 2002
DNS Configuration Options for DHCPv6 DNS Configuration options for DHCPv6
draft-ietf-dhc-dhcpv6-opt-dnsconfig-00.txt draft-ietf-dhc-dhcpv6-opt-dnsconfig-01.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 41 skipping to change at page 1, line 31
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on July 2, 2002. This Internet-Draft will expire on September 30, 2002.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved. Copyright (C) The Internet Society (2002). All Rights Reserved.
Abstract Abstract
This document describes three options for DNS-related configuration This document describes DHCPv6 options for passing a list of
information in DHCPv6: DNS Servers, Domain Name, Domain Search list. available DNS Servers and a domain search list to a client.
1. Introduction 1. Introduction
This document describes three options for configuration information This document describes three options for configuration information
related to Domain Name Service (DNS) [1, 2] in DHCPv6 [5]. related to Domain Name Service (DNS) [1, 2] in DHCPv6 [4].
2. Requirements 2. Requirements
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL in this document are to be
document, are to be interpreted as described in RFC 2119 [1] interpreted as described in RFC2119 [3].
3. Terminology 3. Terminology
This document uses terminology specific to IPv6 and DHCPv6 as defined This document uses terminology specific to IPv6 and DHCPv6 as defined
in section "Terminology" of the DHCP specification. in section "Terminology" of the DHCP specification.
4. Domain Name Server option 4. Domain Name Server option
The Domain Name Server option provides a list of one or more IP The Domain Name Server option provides a list of one or more IP
addresses of DNS servers to which a client's DNS resolver MAY send addresses of DNS servers to which a client's DNS resolver MAY send
DNS queries [3]. The DNS servers SHOULD be listed in the order of DNS queries [2]. The DNS servers are listed in the order of
preference for use by the client resolver. preference for use by the client resolver.
The format of the Domain Name Server option is: The format of the Domain Name 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_DNS_SERVERS | option-len | | OPTION_DNS_SERVERS | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| DNS server (IP address) | | DNS-server (IP address) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| DNS server (IP address) | | DNS-server (IP address) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | | ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_DNS_SERVERS option-code: OPTION_DNS_SERVERS (tbd)
option-length: Length of the 'options' field in octets; must be a option-length: Length of the 'options' field in octets; must be a
multiple of 16 multiple of 16
DNS server: IP address of DNS server DNS-server: IP address of DNS server
5. Domain Name option
The Domain Name option is used by the server to inform the client of
the domain name the client should append to its host name to form the
client's fully qualified domain name (FQDN).
The format of the Domain Name option is:
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_DOMAIN_NAME | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| domain-name |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_DOMAIN_NAME (tbd)
option-length: Length of the 'domain-name' field in octets
domain-name: Domain name for client
The 'domain-name' MUST be encoded as specified in section
"Representation and use of domain names" of the DHCPv6 specification
[5].
Local client policy MAY choose to override the domain-name supplied
in the Domain-Name option with a locally configured value.
6. Domain Search List option 5. Domain Search List option
In some circumstances, it is useful for the DHCP client to be A server sends a Domain Search List option to the DHCP client to
configured with list of domain names to be appended to a host name specify the domain search list the client is to use when resolving
when resolving DNS name. This document defines a new DHCP option hostnames with DNS. This option does not apply to other name
which is passed from the DHCP server to the DHCP client to specify resolution mechanisms.
the domain search list used when resolving hostnames with DNS. This
option does not apply to other name resolution mechanisms.
The format of the Domain Search option is: The format of the Domain Search 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_DOMAIN_LIST | option-len | | OPTION_DOMAIN_LIST | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| searchstring | | searchstring |
| ... | | ... |
skipping to change at page 4, line 25 skipping to change at page 3, line 27
option-code: OPTION_DOMAIN_LIST (tbd) option-code: OPTION_DOMAIN_LIST (tbd)
option-length: Length of the 'searchstring' field in octets option-length: Length of the 'searchstring' field in octets
searchstring: The specification of the list of domain names in the searchstring: The specification of the list of domain names in the
Domain Search List Domain Search List
The list of domain names in the 'searchstring' MUST be encoded as The list of domain names in the 'searchstring' MUST be encoded as
specified in section "Representation and use of domain names" of the specified in section "Representation and use of domain names" of the
DHCPv6 specification [5]. DHCPv6 specification [4].
Local client policy MAY choose to override the domain search list
supplied in the Domain Search List option with a locally configured
value.
7. Appearance of these option 6. Appearance of these options
The Domain Name Server option MUST appear only in the following The Domain Name Server option MUST appear only in the following
messages: Solicit, Advertise, Request, Confirm, Renew, Rebind, messages: Solicit, Advertise, Request, Confirm, Renew, Rebind,
Information-Request, Reply. Information-Request, Reply
The Domain Name option MUST appear only in the following messages:
Solicit, Advertise, Request, Confirm, Renew, Rebind, Information-
Request, Reply.
The Domain Search List option MUST appear only in the following The Domain Search List option MUST appear only in the following
messages: Solicit, Advertise, Request, Confirm, Renew, Rebind, messages: Solicit, Advertise, Request, Confirm, Renew, Rebind,
Information-Request, Reply. Note that the Domain Search List option Information-Request, Reply
will only appear in a Solicit message if the client has a preferred
search list that it is supplying to the server as a hint.
8. Security Considerations 7. Security Considerations
The Domain Name Server option may be used by an intruder DHCP server The Domain Name Server option may be used by an intruder DHCP server
to cause DHCP clients to send DNS queries to an intruder DNS server. to cause DHCP clients to send DNS queries to an intruder DNS server.
The results of these misdirected DNS queries may be used to spoof DNS The results of these misdirected DNS queries may be used to spoof DNS
names. names.
The Domain Name option may be used by an intruder DHCP server to The Domain Name option may be used by an intruder DHCP server to
configure a DHCP client with an invalid domain name, which could be configure a DHCP client with an invalid domain name, which could be
used as a denial of service attack. used as a denial of service attack.
The Domain Search List option may be used by an intruder DHCP server The Domain Search List option may be used by an intruder DHCP server
to cause DHCP clients to search through invalid domains for to cause DHCP clients to search through invalid domains for
incompletely specified domain names. The results of these incompletely specified domain names. The results of these
skipping to change at page 5, line 19 skipping to change at page 4, line 12
configure a DHCP client with an invalid domain name, which could be configure a DHCP client with an invalid domain name, which could be
used as a denial of service attack. used as a denial of service attack.
The Domain Search List option may be used by an intruder DHCP server The Domain Search List option may be used by an intruder DHCP server
to cause DHCP clients to search through invalid domains for to cause DHCP clients to search through invalid domains for
incompletely specified domain names. The results of these incompletely specified domain names. The results of these
misdirected searches may be used to spoof DNS names. misdirected searches may be used to spoof DNS names.
To avoid attacks through the Domain Name Server option and the Domain To avoid attacks through the Domain Name Server option and the Domain
Name option, the DHCP client SHOULD use authenticated DHCP (see Name option, the DHCP client SHOULD use authenticated DHCP (see
section "Authentication of DHCP messages" in the DHCPv6 specification section "Authentication of DHCP messages" in the DHCPv6
[5]. specification).
Because the Domain Search List option may be used to spoof DNS name Because the Domain Search List option may be used to spoof DNS name
resolution in a way that cannot be detected by DNS security resolution in a way that cannot be detected by DNS security
mechanisms like DNSSEC [4], DHCP clients and servers MUST use mechanisms like DNSSEC [5], DHCP clients and servers MUST use
authenticated DHCP when a Domain Search List option is included in a authenticated DHCP when a Domain Search List option is included in a
DHCP message. DHCP message.
9. IANA Considerations 8. IANA Considerations
IANA is requested to assign an option code to these options from the IANA is requested to assign an option code to these options from the
option-code space defined in section "DHCPv6 Options" of the DHCPv6 option-code space defined in section "DHCPv6 Options" of the DHCPv6
specification [5]. specification [4].
References References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Mockapetris, P., "Domain names - concepts and facilities", STD
Levels", BCP 14, RFC 2119, March 1997.
[2] Mockapetris, P., "Domain names - concepts and facilities", STD
13, RFC 1034, November 1987. 13, RFC 1034, November 1987.
[3] Mockapetris, P., "Domain names - implementation and [2] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
[4] Eastlake, D., "Domain Name System Security Extensions", RFC [3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
2535, March 1999. Levels", BCP 14, RFC 2119, March 1997.
[5] Bound, J., Carney, M., Perkins, C., Lemon, T., Volz, B. and R. [4] Bound, J., Carney, M., Perkins, C., Lemon, T., Volz, B. and R.
Droms (ed.), "Dynamic Host Configuration Protocol for IPv6 Droms (ed.), "Dynamic Host Configuration Protocol for IPv6
(DHCPv6)", draft-ietf-dhc-dhcpv6-23 (work in progress), February (DHCPv6)", draft-ietf-dhc-dhcpv6-23 (work in progress), February
2002. 2002.
Authors' Addresses [5] Eastlake, D., "Domain Name System Security Extensions", RFC
2535, March 1999.
Jim Bound
Compaq Computer Corporation
ZK3-3/W20
110 Spit Brook Road
Nashua, NH 03062-2698
USA
Phone: +1 603 884 0062
EMail: Jim.Bound@compaq.com
Mike Carney
Sun Microsystems, Inc.
Mail Stop: UMPK17-202
901 San Antonio Road
Palo Alto, CA 94303-4900
USA>
Phone: +1 650 786 4171
EMail: mwc@eng.sun.com
Charlie Perkins
Nokia Research Center
Communications Systems Lab
313 Fairchild Drive
Mountain View, CA 94043
USA
Phone: +1 650 625 2503
EMail: charliep@iprg.nokia.com
Nominum
EMail: mellon@nominum.com
Bernie Volz Author's Address
Ericsson
959 Concord Street
Framingham, MA 01701
USA
Phone: +1 508 875 3162 Ralph Droms (ed.)
EMail: bernie.volz@ericsson.com
Ralph Droms
Cisco Systems Cisco Systems
250 Apollo Drive 250 Apollo Drive
Chelmsford, MA 01824 Chelmsford, MA 01824
USA USA
Phone: +1 978 497 4733 Phone: +1 978 497 4733
EMail: rdroms@cisco.com EMail: rdroms@cisco.com
Full Copyright Statement Full Copyright Statement
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/