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<html><head><title>A method for storing IPsec keying material in DNS.</title>
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<table width="66%" border="0" cellpadding="0" cellspacing="0"><tr><td><table width="100%" border="0" cellpadding="2" cellspacing="1">
<tr valign="top"><td width="33%" bgcolor="#666666" class="header">IPSECKEY WG</td><td width="33%" bgcolor="#666666" class="header">M. Richardson</td></tr>
<tr valign="top"><td width="33%" bgcolor="#666666" class="header">Internet-Draft</td><td width="33%" bgcolor="#666666" class="header">SSW</td></tr>
<tr valign="top"><td width="33%" bgcolor="#666666" class="header">Expires: March 4, 2004</td><td width="33%" bgcolor="#666666" class="header">September 4, 2003</td></tr>
</table></td></tr></table>
<div align="right"><font face="monaco, MS Sans Serif" color="#990000" size="+3"><b><br><span class="title">A method for storing IPsec keying material in DNS.</span></b></font></div>
<div align="right"><font face="monaco, MS Sans Serif" color="#666666" size="+2"><b><span class="filename">draft-ietf-ipseckey-rr-07.txt</span></b></font></div>
<font face="verdana, helvetica, arial, sans-serif" size="2">
<h3>Status of this Memo</h3>
<p>
This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026.</p>
<p>
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups.
Note that other groups may also distribute working documents as
Internet-Drafts.</p>
<p>
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any time.
It is inappropriate to use Internet-Drafts as reference material or to cite
them other than as "work in progress."</p>
<p>
The list of current Internet-Drafts can be accessed at
<a href='http://www.ietf.org/ietf/1id-abstracts.txt'>http://www.ietf.org/ietf/1id-abstracts.txt</a>.</p>
<p>
The list of Internet-Draft Shadow Directories can be accessed at
<a href='http://www.ietf.org/shadow.html'>http://www.ietf.org/shadow.html</a>.</p>
<p>
This Internet-Draft will expire on March 4, 2004.</p>
<h3>Copyright Notice</h3>
<p>
Copyright (C) The Internet Society (2003). All Rights Reserved.</p>
<h3>Abstract</h3>
<p>
This document describes a new resource record for DNS. This record may be
used to store public keys for use in IPsec systems.
</p>
<p>
This record replaces the functionality of the sub-type #1 of the KEY Resource
Record, which has been obsoleted by RFC3445.
</p><a name="toc"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<h3>Table of Contents</h3>
<ul compact class="toc">
<b><a href="#anchor1">1.</a>
Introduction<br></b>
<b><a href="#anchor2">1.1</a>
Overview<br></b>
<b><a href="#anchor3">1.2</a>
Usage Criteria<br></b>
<b><a href="#anchor4">2.</a>
Storage formats<br></b>
<b><a href="#anchor5">2.1</a>
IPSECKEY RDATA format<br></b>
<b><a href="#anchor6">2.2</a>
RDATA format - precedence<br></b>
<b><a href="#algotype">2.3</a>
RDATA format - algorithm type<br></b>
<b><a href="#gatewaytype">2.4</a>
RDATA format - gateway type<br></b>
<b><a href="#anchor7">2.5</a>
RDATA format - gateway<br></b>
<b><a href="#anchor8">2.6</a>
RDATA format - public keys<br></b>
<b><a href="#anchor9">3.</a>
Presentation formats<br></b>
<b><a href="#anchor10">3.1</a>
Representation of IPSECKEY RRs<br></b>
<b><a href="#anchor11">3.2</a>
Examples<br></b>
<b><a href="#anchor12">4.</a>
Security Considerations<br></b>
<b><a href="#anchor13">4.1</a>
Active attacks against unsecured IPSECKEY resource records<br></b>
<b><a href="#anchor14">5.</a>
IANA Considerations<br></b>
<b><a href="#anchor15">6.</a>
Acknowledgments<br></b>
<b><a href="#rfc.references1">§</a>
Normative references<br></b>
<b><a href="#rfc.references2">§</a>
Non-normative references<br></b>
<b><a href="#rfc.authors">§</a>
Author's Address<br></b>
<b><a href="#rfc.copyright">§</a>
Full Copyright Statement<br></b>
</ul>
<br clear="all">
<a name="anchor1"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<a name="rfc.section.1"></a><h3>1. Introduction</h3>
<p>
The type number for the IPSECKEY RR is TBD.
</p>
<a name="rfc.section.1.1"></a><h4><a name="anchor2">1.1</a> Overview</h4>
<p>
The IPSECKEY resource record (RR) is used to publish a public key that is
to be associated with a Domain Name System (DNS) name for use with the
IPsec protocol suite. This can be the public key of a host,
network, or application (in the case of per-port keying).
</p>
<p>
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 <a href="#RFC2119">[8]</a>.
</p>
<a name="rfc.section.1.2"></a><h4><a name="anchor3">1.2</a> Usage Criteria</h4>
<p>
An IPSECKEY resource record SHOULD be used in combination with DNSSEC
unless some other means of authenticating the IPSECKEY resource record
is available.
</p>
<p>
It is expected that there will often be multiple IPSECKEY resource
records at the same name. This will be due to the presence
of multiple gateways and the need to rollover keys.
</p>
<p>
This resource record is class independent.
</p>
<a name="anchor4"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<a name="rfc.section.2"></a><h3>2. Storage formats</h3>
<a name="rfc.section.2.1"></a><h4><a name="anchor5">2.1</a> IPSECKEY RDATA format</h4>
<p>
The RDATA for an IPSECKEY RR consists of a precedence value, a public key,
algorithm type, and an optional gateway address.
</p></font><pre>
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| precedence | gateway type | algorithm | gateway |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------+ +
~ gateway ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| /
/ public key /
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
<a name="rfc.section.2.2"></a><h4><a name="anchor6">2.2</a> RDATA format - precedence</h4>
<p>
This is an 8-bit precedence for this record. This is interpreted in
the same way as the PREFERENCE field described in section
3.3.9 of RFC1035 <a href="#RFC1035">[2]</a>.
</p>
<p>
Gateways listed in IPSECKEY records with lower precedence are
to be attempted first. Where there is a tie in precedence, the order
should be non-deterministic.
</p>
<a name="rfc.section.2.3"></a><h4><a name="algotype">2.3</a> RDATA format - algorithm type</h4>
<p>
The algorithm type field identifies the public key's cryptographic
algorithm and determines the format of the public key field.
</p>
<p>
A value of 0 indicates that no key is present.
</p>
<p>
The following values are defined:
<blockquote class="text"><dl>
<dt>1</dt>
<dd>A DSA key is present, in the format defined in RFC2536 <a href="#RFC2536">[11]</a>
</dd>
<dt>2</dt>
<dd>A RSA key is present, in the format defined in RFC3110 <a href="#RFC3110">[12]</a>
</dd>
</dl></blockquote><p>
</p>
<a name="rfc.section.2.4"></a><h4><a name="gatewaytype">2.4</a> RDATA format - gateway type</h4>
<p>
The gateway type field indicates the format of the information that
is stored in the gateway field.
</p>
<p>
The following values are defined:
<blockquote class="text"><dl>
<dt>0</dt>
<dd>No gateway is present
</dd>
<dt>1</dt>
<dd>A 4-byte IPv4 address is present
</dd>
<dt>2</dt>
<dd>A 16-byte IPv6 address is present
</dd>
<dt>3</dt>
<dd>A wire-encoded domain name is present. The wire-encoded
format is self-describing, so the length is implicit. The domain name
MUST NOT be compressed.
</dd>
</dl></blockquote><p>
</p>
<a name="rfc.section.2.5"></a><h4><a name="anchor7">2.5</a> RDATA format - gateway</h4>
<p>
The gateway field indicates a gateway to which an IPsec tunnel may be
created in order to reach the entity named by this resource record.
</p>
<p>
There are three formats:
</p>
<p>
A 32-bit IPv4 address is present in the gateway field. The data
portion is an IPv4 address as described in section 3.4.1 of
<a href="#RFC1035">RFC1035</a>[2]. This is a 32-bit number in network byte order.
</p>
<p>A 128-bit IPv6 address is present in the gateway field.
The data portion is an IPv6 address as described in section 2.2 of
<a href="#RFC1886">RFC1886</a>[7]. This is a 128-bit number in network byte order.
</p>
<p>
The gateway field is a normal wire-encoded domain name, as described
in section 3.3 of RFC1035 <a href="#RFC1035">[2]</a>. Compression MUST NOT be used.
</p>
<a name="rfc.section.2.6"></a><h4><a name="anchor8">2.6</a> RDATA format - public keys</h4>
<p>
Both of the public key types defined in this document (RSA and DSA)
inherit their public key formats from the corresponding KEY RR formats.
Specifically, the public key field contains the algorithm-specific
portion of the KEY RR RDATA, which is all of the KEY RR DATA after the
first four octets. This is the same portion of the KEY RR that must be
specified by documents that define a DNSSEC algorithm.
Those documents also specify a message digest to be used for generation
of SIG RRs; that specification is not relevant for IPSECKEY RR.
</p>
<p>
Future algorithms, if they are to be used by both DNSSEC (in the KEY
RR) and IPSECKEY, are likely to use the same public key encodings in
both records. Unless otherwise specified, the IPSECKEY public key
field will contain the algorithm-specific portion of the KEY RR RDATA
for the corresponding algorithm. The algorithm must still be
designated for use by IPSECKEY, and an IPSECKEY algorithm type number
(which might be different than the DNSSEC algorithm number) must be
assigned to it.
</p>
<p>The DSA key format is defined in RFC2536 <a href="#RFC2536">[11]</a>
</p>
<p>The RSA key format is defined in RFC3110 <a href="#RFC3110">[12]</a>,
with the following changes:
</p>
<p>
The earlier definition of RSA/MD5 in RFC2065 limited the exponent and
modulus to 2552 bits in length. RFC3110 extended that limit to 4096
bits for RSA/SHA1 keys. The IPSECKEY RR imposes no length limit on
RSA public keys, other than the 65535 octet limit imposed by the
two-octet length encoding. This length extension is applicable only
to IPSECKEY and not to KEY RRs.
</p>
<a name="anchor9"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<a name="rfc.section.3"></a><h3>3. Presentation formats</h3>
<a name="rfc.section.3.1"></a><h4><a name="anchor10">3.1</a> Representation of IPSECKEY RRs</h4>
<p>
IPSECKEY RRs may appear in a zone data master file.
The precedence, gateway type and algorithm and gateway fields are REQUIRED.
The base64 encoded public key block is OPTIONAL; if not present,
then the public key field of the resource record MUST be construed
as being zero octets in length.
</p>
<p>
The algorithm field is an unsigned integer. No mnemonics are defined.
</p>
<p>
If no gateway is to be indicated, then the gateway type field MUST
be zero, and the gateway field MUST be "."
</p>
<p>
The Public Key field is represented as a Base64 encoding of the
Public Key. Whitespace is allowed within the Base64 text. For a
definition of Base64 encoding, see
<a href="#RFC1521">RFC1521</a>[3] Section 5.2.
</p>
<p>
The general presentation for the record as as follows:
</p>
</font><pre>
IN IPSECKEY ( precedence gateway-type algorithm
gateway base64-encoded-public-key )
</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
<p>
</p>
<a name="rfc.section.3.2"></a><h4><a name="anchor11">3.2</a> Examples</h4>
<p>
An example of a node 192.0.2.38 that will accept IPsec tunnels on its
own behalf.
</p>
</font><pre>
38.2.0.192.in-addr.arpa. 7200 IN IPSECKEY ( 10 1 2
192.0.2.38
AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
<p>
</p>
<p>
An example of a node, 192.0.2.38 that has published its key only.
</p>
</font><pre>
38.2.0.192.in-addr.arpa. 7200 IN IPSECKEY ( 10 0 2
.
AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
<p>
</p>
<p>
An example of a node, 192.0.2.38 that has delegated authority to the node
192.0.2.3.
</p>
</font><pre>
38.2.0.192.in-addr.arpa. 7200 IN IPSECKEY ( 10 1 2
192.0.2.3
AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
<p>
</p>
<p>
An example of a node, 192.0.1.38 that has delegated authority to the node
with the identity "mygateway.example.com".
</p>
</font><pre>
38.1.0.192.in-addr.arpa. 7200 IN IPSECKEY ( 10 3 2
mygateway.example.com.
AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
<p>
</p>
<p>
An example of a node, 2001:0DB8:0200:1:210:f3ff:fe03:4d0 that has
delegated authority to the node 2001:0DB8:c000:0200:2::1
</p>
</font><pre>
$ORIGIN 1.0.0.0.0.0.2.8.B.D.0.1.0.0.2.ip6.int.
0.d.4.0.3.0.e.f.f.f.3.f.0.1.2.0 7200 IN IPSECKEY ( 10 2 2
2001:0DB8:0:8002::2000:1
AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
<p>
</p>
<a name="anchor12"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<a name="rfc.section.4"></a><h3>4. Security Considerations</h3>
<p>
This entire memo pertains to the provision of public keying material
for use by key management protocols such as ISAKMP/IKE (RFC2407)
<a href="#RFC2407">[9]</a>.
</p>
<p>
The IPSECKEY resource record contains information that SHOULD be
communicated to the end client in an integral fashion - i.e. free from
modification. The form of this channel is up to the consumer of the
data - there must be a trust relationship between the end consumer of this
resource record and the server. This relationship may be end-to-end
DNSSEC validation, a TSIG or SIG(0) channel to another secure source,
a secure local channel on the host, or some combination of the above.
</p>
<p>
The keying material provided by the IPSECKEY resource record is not
sensitive to passive attacks. The keying material may be freely
disclosed to any party without any impact on the security properties
of the resulting IPsec session: IPsec and IKE provide for defense
against both active and passive attacks.
</p>
<p>
Any user of this resource record MUST carefully document their trust
model, and why the trust model of DNSSEC is appropriate, if that is
the secure channel used.
</p>
<a name="rfc.section.4.1"></a><h4><a name="anchor13">4.1</a> Active attacks against unsecured IPSECKEY resource records</h4>
<p>
This section deals with active attacks against the DNS. These attacks
require that DNS requests and responses be intercepted and changed.
DNSSEC is designed to defend against attacks of this kind.
</p>
<p>
The first kind of active attack is when the attacker replaces the
keying material with either a key under its control or with garbage.
</p>
<p>
If the attacker is not able to mount a subsequent
man-in-the-middle attack on the IKE negotiation after replacing the
public key, then this will result in a denial of service, as the
authenticator used by IKE would fail.
</p>
<p>
If the attacker is able to both to mount active attacks against DNS
and is also in a position to perform a man-in-the-middle attack on IKE and
IPsec negotiations, then the attacker will be in a position to compromise
the resulting IPsec channel. Note that an attacker must be able to
perform active DNS attacks on both sides of the IKE negotiation in
order for this to succeed.
</p>
<p>
The second kind of active attack is one in which the attacker replaces
the the gateway address to point to a node under the attacker's
control. The attacker can then either replace the public key or remove
it, thus providing an IPSECKEY record of its own to match the
gateway address.
</p>
<p>
This later form creates a simple man-in-the-middle since the attacker
can then create a second tunnel to the real destination. Note that, as before,
this requires that the attacker also mount an active attack against
the responder.
</p>
<p>
Note that the man-in-the-middle can not just forward cleartext
packets to the original destination. While the destination may be
willing to speak in the clear, replying to the original sender,
the sender will have already created a policy expecting ciphertext.
Thus, the attacker will need to intercept traffic from both sides. In some
cases, the attacker may be able to accomplish the full intercept by use
of Network Addresss/Port Translation (NAT/NAPT) technology.
</p>
<p>
Note that the danger here only applies to cases where the gateway
field of the IPSECKEY RR indicates a different entity than the owner
name of the IPSECKEY RR. In cases where the end-to-end integrity of
the IPSECKEY RR is suspect, the end client MUST restrict its use
of the IPSECKEY RR to cases where the RR owner name matches the
content of the gateway field.
</p>
<a name="anchor14"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<a name="rfc.section.5"></a><h3>5. IANA Considerations</h3>
<p>
This document updates the IANA Registry for DNS Resource Record Types
by assigning type X to the IPSECKEY record.
</p>
<p>
This document creates an IANA registry for the algorithm type field.
</p>
<p>
Values 0, 1 and 2 are defined in <a href="#algotype">RDATA format - algorithm type</a>. Algorithm numbers
3 through 255 can be assigned by IETF Consensus (<a href="#RFC2434">see RFC2434</a>[6]).
</p>
<p>
This document creates an IANA registry for the gateway type field.
</p>
<p>
Values 0, 1, 2 and 3 are defined in <a href="#gatewaytype">RDATA format - gateway type</a>.
Algorithm numbers 4 through 255 can be assigned by
Standards Action (<a href="#RFC2434">see RFC2434</a>[6]).
</p>
<a name="anchor15"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<a name="rfc.section.6"></a><h3>6. Acknowledgments</h3>
<p>
My thanks to Paul Hoffman, Sam Weiler, Jean-Jacques Puig, Rob Austein,
and Olafur Gurmundsson who reviewed this document carefully.
Additional thanks to Olafur Gurmundsson for a reference implementation.
</p>
<a name="rfc.references1"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<h3>Normative references</h3>
<table width="99%" border="0">
<tr><td class="author-text" valign="top"><b><a name="RFC1034">[1]</a></b></td>
<td class="author-text">Mockapetris, P., "<a href="ftp://ftp.isi.edu/in-notes/rfc1034.txt">Domain names - concepts and facilities</a>", STD 13, RFC 1034, November 1987.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC1035">[2]</a></b></td>
<td class="author-text"><a href="mailto:">Mockapetris, P.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1035.txt">Domain names - implementation and specification</a>", STD 13, RFC 1035, November 1987.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC1521">[3]</a></b></td>
<td class="author-text"><a href="mailto:nsb@bellcore.com">Borenstein, N.</a> and <a href="mailto:">N. Freed</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1521.txt">MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies</a>", RFC 1521, September 1993.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC2026">[4]</a></b></td>
<td class="author-text"><a href="mailto:sob@harvard.edu">Bradner, S.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2026.txt">The Internet Standards Process -- Revision 3</a>", BCP 9, RFC 2026, October 1996.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC2065">[5]</a></b></td>
<td class="author-text"><a href="mailto:dee@cybercash.com">Eastlake, D.</a> and <a href="mailto:charlie_kaufman@iris.com">C. Kaufman</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2065.txt">Domain Name System Security Extensions</a>", RFC 2065, January 1997.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC2434">[6]</a></b></td>
<td class="author-text"><a href="mailto:narten@raleigh.ibm.com">Narten, T.</a> and <a href="mailto:Harald@Alvestrand.no">H. Alvestrand</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2434.txt">Guidelines for Writing an IANA Considerations Section in RFCs</a>", BCP 26, RFC 2434, October 1998.</td></tr>
</table>
<a name="rfc.references2"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<h3>Non-normative references</h3>
<table width="99%" border="0">
<tr><td class="author-text" valign="top"><b><a name="RFC1886">[7]</a></b></td>
<td class="author-text"><a href="mailto:set@thumper.bellcore.com">Thomson, S.</a> and <a href="mailto:Christian.Huitema@MIRSA.INRIA.FR">C. Huitema</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1886.txt">DNS Extensions to support IP version 6</a>", RFC 1886, December 1995.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC2119">[8]</a></b></td>
<td class="author-text"><a href="mailto:-">Bradner, S.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2119.txt">Key words for use in RFCs to Indicate Requirement Levels</a>", BCP 14, RFC 2119, March 1997.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC2407">[9]</a></b></td>
<td class="author-text"><a href="mailto:ddp@network-alchemy.com">Piper, D.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2407.txt">The Internet IP Security Domain of Interpretation for ISAKMP</a>", RFC 2407, November 1998.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC2535">[10]</a></b></td>
<td class="author-text"><a href="mailto:dee3@us.ibm.com">Eastlake, D.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2535.txt">Domain Name System Security Extensions</a>", RFC 2535, March 1999.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC2536">[11]</a></b></td>
<td class="author-text"><a href="mailto:dee3@us.ibm.com">Eastlake, D.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2536.txt">DSA KEYs and SIGs in the Domain Name System (DNS)</a>", RFC 2536, March 1999.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC3110">[12]</a></b></td>
<td class="author-text">Eastlake, D., "<a href="ftp://ftp.isi.edu/in-notes/rfc3110.txt">RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System (DNS)</a>", RFC 3110, May 2001.</td></tr>
<tr><td class="author-text" valign="top"><b><a name="RFC3445">[13]</a></b></td>
<td class="author-text">Massey, D. and S. Rose, "<a href="ftp://ftp.isi.edu/in-notes/rfc3445.txt">Limiting the Scope of the KEY Resource Record (RR)</a>", RFC 3445, December 2002.</td></tr>
</table>
<a name="rfc.authors"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<h3>Author's Address</h3>
<table width="99%" border="0" cellpadding="0" cellspacing="0">
<tr><td class="author-text"> </td>
<td class="author-text">Michael C. Richardson</td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">Sandelman Software Works</td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">470 Dawson Avenue</td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">Ottawa, ON K1Z 5V7</td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">CA</td></tr>
<tr><td class="author" align="right">EMail: </td>
<td class="author-text"><a href="mailto:mcr@sandelman.ottawa.on.ca">mcr@sandelman.ottawa.on.ca</a></td></tr>
<tr><td class="author" align="right">URI: </td>
<td class="author-text"><a href="http://www.sandelman.ottawa.on.ca/">http://www.sandelman.ottawa.on.ca/</a></td></tr>
</table>
<a name="rfc.copyright"><br><hr size="1" shade="0"></a>
<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b> TOC </b></font></a><br></td></tr></table>
<h3>Full Copyright Statement</h3>
<p class='copyright'>
Copyright (C) The Internet Society (2003). All Rights Reserved.</p>
<p class='copyright'>
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.</p>
<p class='copyright'>
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.</p>
<p class='copyright'>
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.</p>
<h3>Acknowledgement</h3>
<p class='copyright'>
Funding for the RFC Editor function is currently provided by the
Internet Society.</p>
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