Network Working Group J. Jeong, Ed.
Internet-Draft Brocade/ETRI
Obsoletes: 5006 (if approved) S. Park
Intended status: Standards Track SAMSUNG Electronics
Expires: November 25, 2010 L. Beloeil
France Telecom R&D
S. Madanapalli
Ordyn Technologies
May 24, 2010
IPv6 Router Advertisement Options for DNS Configuration RFC 5006-bis
draft-ietf-6man-dns-options-bis-02
Abstract
This document specifies IPv6 Router Advertisement options to allow
IPv6 routers to advertise a list of DNS recursive server addresses
and a DNS search list to IPv6 hosts.
Status of This Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
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This Internet-Draft will expire on November 25, 2010.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://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 and restrictions with respect
to this document. Code Components extracted from this document must
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Applicability Statements . . . . . . . . . . . . . . . . . 3
1.2. Coexistence of RA Options and DHCP Options for DNS
Configuration . . . . . . . . . . . . . . . . . . . . . . 4
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Neighbor Discovery Extension . . . . . . . . . . . . . . . . . 5
5.1. Recursive DNS Server Option . . . . . . . . . . . . . . . 5
5.2. DNS Search List Option . . . . . . . . . . . . . . . . . . 7
5.3. Procedure of DNS Configuration . . . . . . . . . . . . . . 8
5.3.1. Procedure in IPv6 Host . . . . . . . . . . . . . . . . 8
6. Implementation Considerations . . . . . . . . . . . . . . . . 9
6.1. DNS Repository Management . . . . . . . . . . . . . . . . 9
6.2. Synchronization between DNS Server List and Resolver
Repository . . . . . . . . . . . . . . . . . . . . . . . . 10
6.3. Synchronization between DNS Search List and Resolver
Repository . . . . . . . . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
10.1. Normative References . . . . . . . . . . . . . . . . . . . 13
10.2. Informative References . . . . . . . . . . . . . . . . . . 14
Appendix A. Changes from RFC 5006 . . . . . . . . . . . . . . . . 14
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1. Introduction
The purpose of this document is to standardize IPv6 Router
Advertisement (RA) option for DNS configuration in IPv6 hosts
specified in an earlier experimental specification [RFC5006] and also
to define a new RA option for Domain Name Search lists.
Neighbor Discovery (ND) for IP Version 6 and IPv6 Stateless Address
Autoconfiguration provide ways to configure either fixed or mobile
nodes with one or more IPv6 addresses, default routers and some other
parameters [RFC4861][RFC4862]. Most Internet services are identified
by using a DNS name. The two RA options defined in this document
provide the DNS information needed for an IPv6 host to reach Internet
services.
It is infeasible to manually configure nomadic hosts each time they
connect to a different network. While a one-time static
configuration is possible, it is generally not desirable on general-
purpose hosts such as laptops. For instance, locally defined name
spaces would not be available to the host if it were to run its own
name server software directly connected to the global DNS.
The DNS information can also be provided through DHCP
[RFC3315][RFC3736][RFC3646]. However, the access to DNS is a
fundamental requirement for almost all hosts, so IPv6 stateless
autoconfiguration cannot stand on its own as an alternative
deployment model in any practical network without any support for DNS
configuration.
These issues are not pressing in dual stack networks as long as a DNS
server is available on the IPv4 side, but become more critical with
the deployment of IPv6-only networks. As a result, this document
defines a mechanism based on IPv6 RA options to allow IPv6 hosts to
perform the automatic DNS configuration.
1.1. Applicability Statements
RA-based DNS configuration is a useful alternative in networks where
an IPv6 host's address is autoconfigured through IPv6 stateless
address autoconfiguration, and where there is either no DHCPv6
infrastructure at all or some hosts do not have a DHCPv6 client. The
intention is to enable the full configuration of basic networking
information for hosts without requiring DHCPv6. However, when in
many networks some additional information needs to be distributed,
those networks are likely to employ DHCPv6. In these networks RA-
based DNS configuration may not be needed.
RA-based DNS configuration allows an IPv6 host to acquire the DNS
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configuration (i.e., DNS recursive server addresses and DNS search
list) for the link(s) to which the host is connected. Furthermore,
the host learns this DNS configuration from the same RA message that
provides configuration information for the link, thereby avoiding
also running DHCPv6.
The advantages and disadvantages of the RA-based approach are
discussed in [RFC4339] along with other approaches, such as the DHCP
and well-known anycast addresses approaches.
1.2. Coexistence of RA Options and DHCP Options for DNS Configuration
Two protocols exist to configure the DNS information on a host, the
Router Advertisement options described in this document and the
DHCPv6 options described in [RFC3646]. They can be used together.
The rules governing the decision to use stateful configuration
mechanisms are specified in [RFC4861]. Hosts conforming to this
specification MUST extract DNS information from Router Advertisement
messages, unless static DNS configuration has been specified by the
user. If there is DNS information available from multiple Router
Advertisements and/or from DHCP, the host MUST maintain an ordered
list of this information as specified in Section 5.3.1.
2. Requirements Language
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 [RFC2119].
3. Terminology
This document uses the terminology described in [RFC4861] and
[RFC4862]. In addition, four new terms are defined below:
o Recursive DNS Server (RDNSS): Server which provides a recursive
DNS resolution service for translating domain names into IP
addresses as defined in [RFC1034] and [RFC1035].
o RDNSS Option: IPv6 RA option to deliver the RDNSS information to
IPv6 hosts [RFC4861].
o DNS Search List (DNSSL): The list of DNS suffix domain names used
by IPv6 hosts when they perform DNS query searches for short,
unqualified domain names.
o DNSSL Option: IPv6 RA option to deliver the DNSSL information to
IPv6 hosts.
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o DNS Repository: Two data structures for managing DNS Configuration
Information in the IPv6 protocol stack in addition to Neighbor
Cache and Destination Cache for Neighbor Discovery [RFC4861]. The
first data structure is the DNS Server List for RDNSS addresses
and the second is the DNS Search List for DNS search domain names.
o Resolver Repository: Configuration repository with RDNSS addresses
and a DNS search list that a DNS resolver on the host uses for DNS
name resolution; for example, the Unix resolver file (i.e., /etc/
resolv.conf) and Windows registry.
4. Overview
This document standardizes the ND option called RDNSS option defined
in [RFC5006] that contains the addresses of recursive DNS servers.
This document also defines a new ND option called DNSSL option for
Domain Search List. This is to maintain parity with the DHCPv6
options and to ensure that there is necessary functionality to
determine the search domains.
Existing ND message (i.e., Router Advertisement) is used to carry
this information. An IPv6 host can configure the IPv6 addresses of
one or more RDNSSes via RA messages. Through the RDNSS and DNSSL
options, along with the prefix information option based on the ND
protocol ([RFC4861] and [RFC4862]), an IPv6 host can perform the
network configuration of its IPv6 address and the DNS information
simultaneously without needing DHCPv6 for the DNS configuration. The
RA options for RDNSS and DNSSL can be used on any network that
supports the use of ND.
This approach requires the manual configuration or other automatic
mechanisms (e.g., DHCPv6 or vendor proprietary configuration
mechanisms) to configure the DNS information in routers sending the
advertisements. The automatic configuration of RDNSS addresses and a
DNS search list in routers is out of scope for this document.
5. Neighbor Discovery Extension
The IPv6 DNS configuration mechanism in this document needs two new
ND options in Neighbor Discovery: (i) the Recursive DNS Server
(RDNSS) option and (ii) the DNS Search List (DNSSL) option.
5.1. Recursive DNS Server Option
The RDNSS option contains one or more IPv6 addresses of recursive DNS
servers. All of the addresses share the same lifetime value. If it
is desirable to have different lifetime values, multiple RDNSS
options can be used. Figure 1 shows the format of the RDNSS option.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: Addresses of IPv6 Recursive DNS Servers :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Recursive DNS Server (RDNSS) Option Format
Fields:
Type 8-bit identifier of the RDNSS option type as assigned
by the IANA: 25
Length 8-bit unsigned integer. The length of the option
(including the Type and Length fields) is in units of
8 octets. The minimum value is 3 if one IPv6 address
is contained in the option. Every additional RDNSS
address increases the length by 2. The Length field
is used by the receiver to determine the number of
IPv6 addresses in the option.
Lifetime 32-bit unsigned integer. The maximum time, in
seconds (relative to the time the packet is sent),
over which this RDNSS address MAY be used for name
resolution. Hosts MAY send a Router Solicitation to
ensure the RDNSS information is fresh before the
interval expires. In order to provide fixed hosts
with stable DNS service and allow mobile hosts to
prefer local RDNSSes to remote RDNSSes, the value of
Lifetime should be at least as long as the Maximum RA
Interval (MaxRtrAdvInterval) in [RFC4861], and be at
most as long as two times MaxRtrAdvInterval; Lifetime
SHOULD be bounded as follows: MaxRtrAdvInterval <=
Lifetime <= 2*MaxRtrAdvInterval. A value of all one
bits (0xffffffff) represents infinity. A value of
zero means that the RDNSS address MUST no longer be
used.
Addresses of IPv6 Recursive DNS Servers
One or more 128-bit IPv6 addresses of the recursive
DNS servers. The number of addresses is determined
by the Length field. That is, the number of
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addresses is equal to (Length - 1) / 2.
5.2. DNS Search List Option
The DNSSL option contains one or more domain names of DNS suffixes.
All of the domain names share the same lifetime value. If it is
desirable to have different lifetime values, multiple DNSSL options
can be used. Figure 2 shows the format of the DNSSL option.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: Domain Names of DNS Search List :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: DNS Search List (DNSSL) Option Format
Fields:
Type 8-bit identifier of the RDNSS option type as assigned
by the IANA: (TBD)
Length 8-bit unsigned integer. The length of the option
(including the Type and Length fields) is in units of
8 octets. The minimum value is 2 if at least one
domain name is contained in the option. The Length
field is set to a multiple of 8 octets to accommodate
all the domain names in the field of Domain Names of
DNS Search List.
Lifetime 32-bit unsigned integer. The maximum time, in
seconds (relative to the time the packet is sent),
over which this DNSSL domain name MAY be used for
name resolution. The Lifetime value has the same
semantics as with RDNSS option. That is, Lifetime
SHOULD be bounded as follows: MaxRtrAdvInterval <=
Lifetime <= 2*MaxRtrAdvInterval. A value of all one
bits (0xffffffff) represents infinity. A value of
zero means that the DNSSL domain name MUST no longer
be used.
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Domain Names of DNS Search List
One or more domain names of DNS search list that MUST
be encoded in the non-compressed form, using the
technique described in Section 3.1 of [RFC1035]. The
size of this field is a multiple of 8 octets. The
remaining octets other than the encoding parts for
the domain names are padded with zeros.
Note: An RDNSS address or a DNSSL domain name MUST be used only as
long as both the RA router lifetime and the option lifetime have
not expired. The reason is that in the current network to which
an IPv6 host is connected, the RDNSS may not be currently
reachable, that the DNSSL domain name is not valid any more, or
that these options do not provide service to the host's current
address (e.g., due to network ingress filtering
[RFC2827][RFC5358]).
5.3. Procedure of DNS Configuration
The procedure of DNS configuration through the RDNSS and DNSSL
options is the same as with any other ND option [RFC4861].
5.3.1. Procedure in IPv6 Host
When an IPv6 host receives DNS options (i.e., RDNSS option and DNSSL
option) through RA messages, it checks whether the options are valid
or not as follow:
o If the DNS options are valid, the host SHOULD copy the values of
the options into the DNS Repository and the Resolver Repository in
order; the value of the Length field in the RDNSS option is
greater than or equal to the minimum value (3) and also the value
of the Length field in the DNSSL option is greater than or equal
to the minimum value (2).
o If the DNS options are invalid, the host MUST discard the options;
for example, the Length field in the RDNSS option has a value less
than 3 or the Length field in the DNSSL option has a value less
than 2.
When the IPv6 host has gathered a sufficient number (e.g., three) of
RDNSS addresses (or DNS search domain names), it MAY ignore
additional RDNSS addresses (or DNS search domain names) within an
RDNSS (or DNSSL) option and/or additional RDNSS (or DNSSL) options
within an RA.
In the case where the DNS options of RDNSS and DNSSL can be obtained
from multiple sources, such as RA and DHCP, the IPv6 host can keep
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some DNS options from RA and some from DHCP; for example, two RDNSS
addresses (or DNS search domain names) from RA and one RDNSS address
(or DNS search domain name) from DHCP.
6. Implementation Considerations
Note: This non-normative section gives some hints for implementing
the processing of the RDNSS and DNSSL options in an IPv6 host.
For the configuration and management of DNS information, the
advertised DNS configuration information can be stored and managed in
both the DNS Repository and the Resolver Repository.
In environments where the DNS information is stored in user space and
ND runs in the kernel, it is necessary to synchronize the DNS
information (i.e., RDNSS addresses and DNS search domain names) in
kernel space and the Resolver Repository in user space. For the
synchronization, an implementation where ND works in the kernel
should provide a write operation for updating DNS information from
the kernel to the Resolver Repository. One simple approach is to
have a daemon (or a program that is called at defined intervals) that
keeps monitoring the lifetimes of RDNSS addresses and DNS search
domain names all the time. Whenever there is an expired entry in the
DNS Repository, the daemon can delete the corresponding entry from
the Resolver Repository.
6.1. DNS Repository Management
For DNS repository management, the kernel or user-space process
(depending on where RAs are processed) should maintain two data
structures: (i) DNS Server List that keeps the list of RDNSS
addresses and (ii) DNS Search List that keeps the list of DNS search
domain names. Each entry in these two lists consists of a pair of an
RDNSS address (or DNSSL domain name) and Expiration-time as follows:
o RDNSS address for DNS Server List: IPv6 address of the Recursive
DNS Server, which is available for recursive DNS resolution
service in the network advertising the RDNSS option.
o DNSSL domain name for DNS Search List: DNS suffix domain names,
which is used to perform DNS query searches for short, unqualified
domain names in the network advertising the DNSSL option.
o Expiration-time for DNS Server List or DNS Search List: The time
when this entry becomes invalid. Expiration-time is set to the
value of the Lifetime field of the RDNSS option or DNSSL option
plus the current system time. Whenever a new RDNSS option with
the same address (or DNSSL option with the same domain name) is
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received on the same interface as a previous RDNSS option (or
DNSSL option), this field is updated to have a new expiration
time. When Expiration-time becomes less than the current system
time, this entry is regarded as expired.
6.2. Synchronization between DNS Server List and Resolver Repository
When an IPv6 host receives the information of multiple RDNSS
addresses within a network (e.g., campus network and company network)
through an RA message with RDNSS option(s), it stores the RDNSS
addresses (in order) into both the DNS Server List and the Resolver
Repository. The processing of the RDNSS option(s) included in an RA
message is as follows:
Step (a): Receive and parse the RDNSS option(s). For the RDNSS
addresses in each RDNSS option, perform Step (b) through Step (d).
Note that Step (e) is performed whenever an entry expires in the
DNS Server List.
Step (b): For each RDNSS address, check the following: If the
RDNSS address already exists in the DNS Server List and the RDNSS
option's Lifetime field is set to zero, delete the corresponding
RDNSS entry from both the DNS Server List and the Resolver
Repository in order to prevent the RDNSS address from being used
any more for certain reasons in network management, e.g., the
termination of the RDNSS or a renumbering situation. The
processing of this RDNSS address is finished here. Otherwise, go
to Step (c).
Step (c): For each RDNSS address, if it already exists in the DNS
Server List, then just update the value of the Expiration-time
field according to the procedure specified in the second bullet of
Section 6.1. Otherwise, go to Step (d).
Step (d): For each RDNSS address, if it does not exist in the DNS
Server List, register the RDNSS address and lifetime with the DNS
Server List and then insert the RDNSS address in front of the
Resolver Repository. In the case where the data structure for the
DNS Server List is full of RDNSS entries, delete from the DNS
Server List the entry with the shortest expiration time (i.e., the
entry that will expire first). The corresponding RDNSS address is
also deleted from the Resolver Repository. In the order in the
RDNSS option, position the newly added RDNSS addresses in front of
the Resolver Repository so that the new RDNSS addresses may be
preferred according to their order in the RDNSS option for the DNS
name resolution. The processing of these RDNSS addresses is
finished here. Note that, in the case where there are several
routers advertising RDNSS option(s) in a subnet, the RDNSSes that
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have been announced recently are preferred.
Step (e): Delete each expired entry from the DNS Server List, and
delete the RDNSS address corresponding to the entry from the
Resolver Repository.
6.3. Synchronization between DNS Search List and Resolver Repository
When an IPv6 host receives the information of multiple DNSSL domain
names within a network (e.g., campus network and company network)
through an RA message with DNSSL option(s), it stores the DNSSL
domain names (in order) into both the DNS Search List and the
Resolver Repository. The processing of the DNSSL option(s) included
in an RA message is as follows:
Step (a): Receive and parse the DNSSL option(s). For the DNSSL
domain names in each DNSSL option, perform Step (b) through Step
(d). Note that Step (e) is performed whenever an entry expires in
the DNS Search List.
Step (b): For each DNSSL domain name, check the following: If the
DNSSL domain name already exists in the DNS Search List and the
DNSSL option's Lifetime field is set to zero, delete the
corresponding DNSSL entry from both the DNS Search List and the
Resolver Repository in order to prevent the DNSSL domain name from
being used any more for certain reasons in network management,
e.g., the termination of the RDNSS or a renaming situation. The
processing of this DNSSL domain name is finished here. Otherwise,
go to Step (c).
Step (c): For each DNSSL domain name, if it already exists in the
DNS Server List, then just update the value of the Expiration-time
field according to the procedure specified in the second bullet of
Section 6.1. Otherwise, go to Step (d).
Step (d): For each DNSSL domain name, if it does not exist in the
DNS Search List, register the DNSSL domain name and lifetime with
the DNS Search List and then insert the DNSSL domain name in front
of the Resolver Repository. In the case where the data structure
for the DNS Search List is full of DNSSL domain name entries,
delete from the DNS Server List the entry with the shortest
expiration time (i.e., the entry that will expire first). The
corresponding DNSSL domain name is also deleted from the Resolver
Repository. In the order in the DNSSL option, position the newly
added DNSSL domain names in front of the Resolver Repository so
that the new DNSSL domain names may be preferred according to
their order in the DNSSL option for the DNS domain name used by
the DNS query. The processing of these DNSSL domain name is
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finished here. Note that, in the case where there are several
routers advertising DNSSL option(s) in a subnet, the DNSSL domain
names that have been announced recently are preferred.
Step (e): Delete each expired entry from the DNS Search List, and
delete the DNSSL domain name corresponding to the entry from the
Resolver Repository.
7. Security Considerations
The security of the RA options for DNS configuration does not affect
ND protocol security [RFC4861]. This is because learning DNS
information via the RA options cannot be worse than learning bad
router information via the RA options. It can be claimed that the
vulnerability of ND is not worse and is a subset of the attacks that
any node attached to a LAN can do independently of ND. A malicious
node on a LAN can promiscuously receive packets for any router's MAC
address and send packets with the router's MAC address as the source
MAC address in the L2 header. As a result, L2 switches send packets
addressed to the router to the malicious node. Also, this attack can
send redirects that tell the hosts to send their traffic somewhere
else. The malicious node can send unsolicited RA or Neighbor
Advertisement (NA) replies, answer RS or Neighbor Solicitation (NS)
requests, etc. Also, an attacker could configure a host to send out
an RA with a fraudulent RDNSS address, which is presumably an easier
avenue of attack than becoming a rogue router and having to process
all traffic for the subnet. It is necessary to disable the RA RDNSS
option or DNSSL option in both routers and clients administratively
to avoid this problem. All of this can be done independently of
implementing ND. Therefore, it can be claimed that the RA options
for RDNSS and DNSSL has vulnerabilities similar to those existing in
unauthenticated DHCPv6.
It is common for network devices such as switches to include
mechanisms to block unauthorized ports from running a DHCPv6 server
to provide protection from rogue DHCP servers. That means that an
attacker on other ports cannot insert bogus DNS servers using DHCPv6.
The corresponding technique for network devices is recommended to
block rogue Router Advertisement messages including the RDNSS and
DNSSL options from unauthorized nodes.
An attacker may provide a bogus DNS Search List option in order to
cause the victim to send DNS queries to a specific DNS server when
the victim queries non-fully qualified domain names. For this
attack, the DNS resolver in IPv6 hosts can mitigate the vulnerability
with the recommendations in [RFC1535], [RFC1536], and [RFC3646].
If the Secure Neighbor Discovery (SEND) protocol is used as a
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security mechanism for ND, all the ND options including the RDNSS and
DNSSL options are automatically included in the signatures [RFC3971],
so the transport for the RA options is integrity-protected. However,
since any valid SEND node can still insert RDNSS and DNSSL options,
SEND cannot verify who is or is not authorized to send the options.
8. IANA Considerations
The RDNSS option defined in this document is using the IPv6 Neighbor
Discovery Option type in RFC 5006 [RFC5006] assigned by the IANA as
follows:
Option Name Type
RDNSS option 25
The IANA is requested to assign a new IPv6 Neighbor Discovery Option
type for the DNSSL option defined in this document:
Option Name Type
DNSSL option (TBD)
The IANA registry for these options is:
http://www.iana.org/assignments/icmpv6-parameters
9. Acknowledgements
This document has greatly benefited from inputs by Robert Hinden,
Pekka Savola, Iljitsch van Beijnum, Brian Haberman, Tim Chown, Erik
Nordmark, Dan Wing, and Jari Arkko. The authors sincerely appreciate
their contributions.
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861,
September 2007.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007.
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10.2. Informative References
[RFC1034] Mockapetris, P., "Domain Names - Concepts and Facilities",
RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain Names - Implementation and
Specification", RFC 1035, November 1987.
[RFC3315] Droms, R., Ed., "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol
(DHCP) Service for IPv6", RFC 3736, April 2004.
[RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic
Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
December 2003.
[RFC5006] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Option for DNS Configuration",
RFC 5006, September 2007.
[RFC4339] Jeong, J., Ed., "IPv6 Host Configuration of DNS Server
Information Approaches", RFC 4339, February 2006.
[RFC3971] Arkko, J., Ed., "SEcure Neighbor Discovery (SEND)",
RFC 3971, March 2005.
[RFC5358] Damas, J. and F. Neves, "Preventing Use of Recursive
Nameservers in Reflector Attacks", BCP 140, RFC 5358,
October 2008.
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, May 2000.
[RFC1535] Gavron, E., "A Security Problem and Proposed Correction
With Widely Deployed DNS Software", RFC 1535,
October 1993.
[RFC1536] Kumar, A., Postel, J., Neuman, C., Danzig, P., and S.
Miller, "Common DNS Implementation Errors and Suggested
Fixes", RFC 1536, October 1993.
Appendix A. Changes from RFC 5006
The following changes were made from RFC 5006 "IPv6 Router
Advertisement Option for DNS Configuration":
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Internet-Draft IPv6 RA DNS Options RFC 5006-bis May 2010
o Added DNS Search List (DNSSL) Option to support the advertisement
of DNS suffixes used in the DNS search along with RDNSS Option in
RFC 5006.
o Clarified the coexistence of RA options and DHCP options for DNS
configuration.
o Modified the procedure in IPv6 host:
* Clarified the procedure for DNS options in an IPv6 host.
* Specified a sufficient number of RDNSS addresses or DNS search
domain names as three.
* Specified a way to deal with DNS options from multiple sources,
such as RA and DHCP.
o Modified implementation considerations for DNSSL Option handling.
o Modified security considerations to consider more attack scenarios
and the corresponding possible solutions.
o Modified IANA considerations to require another IPv6 Neighbor
Discovery Option type for DNSSL option.
Authors' Addresses
Jaehoon Paul Jeong (editor)
Brocade Communications Systems/ETRI
6000 Nathan Ln N
Plymouth, MN 55442
USA
Phone: +1 763 268 7173
Fax: +1 763 268 6800
EMail: pjeong@brocade.com
URI: http://www.cs.umn.edu/~jjeong/
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Internet-Draft IPv6 RA DNS Options RFC 5006-bis May 2010
Soohong Daniel Park
Mobile Platform Laboratory
SAMSUNG Electronics
416 Maetan-3dong, Yeongtong-Gu
Suwon, Gyeonggi-Do 443-742
Korea
Phone: +82 31 200 4508
EMail: soohong.park@samsung.com
Luc Beloeil
France Telecom R&D
42, rue des coutures
BP 6243
14066 CAEN Cedex 4
France
Phone: +33 02 3175 9391
EMail: luc.beloeil@orange-ftgroup.com
Syam Madanapalli
Ordyn Technologies
1st Floor, Creator Building, ITPL
Bangalore - 560066
India
Phone: +91-80-40383000
EMail: smadanapalli@gmail.com
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