Network Working Group                                          W. Kumari
Internet-Draft                                                    Google
Intended status: Standards Track                                 E. Hunt
Expires: March 25, June 23, 2019                                               ISC
                                                               R. Arends
                                                                   ICANN
                                                             W. Hardaker
                                                                 USC/ISI
                                                             D. Lawrence
                                                            Oracle + Dyn
                                                      September 21,
                                                       December 20, 2018

                          Extended DNS Errors
                   draft-ietf-dnsop-extended-error-02
                   draft-ietf-dnsop-extended-error-03

Abstract

   This document defines an extensible method to return additional
   information about the cause of DNS errors.  The primary use case is  Though created primarily
   to extend SERVFAIL to provide additional information about the cause
   of DNS and DNSSEC failures. failures, the Extended DNS Errors option defined in
   this document allows all response types to contain extended error
   information.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/. http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on March 25, June 23, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction and background . . . . . . . . . . . . . . . . .   2   3
     1.1.  Requirements notation . . . . . . . . . . . . . . . . . .   3
   2.  Extended Error EDNS0 option format  . . . . . . . . . . . . .   3
   3.  Use of the Extended DNS Error option  . . . . . . . . . . . .   4
     3.1.  The R (Retry) flag  . . . . . . . . . . . . . . . . . . .   5
   4.  Defined Extended DNS Errors
     3.2.  The RESPONSE-CODE field . . . . . . . . . . . . . . . . .   5
     4.1.  SERVFAIL(2) extended information codes
     3.3.  The INFO-CODE field . . . . . . . . . . . . . . . . . . .   5
     3.4.  The EXTRA-TEXT field  . . . . . . . . . . . . . . . . . .   5
   4.  Defined Extended DNS Errors . . . . . . . . . . . . . . . . .   5
     4.1.  INFO-CODEs for use with RESPONSE-CODE: SERVFAIL(2)  . . .   6
       4.1.1.  SERVFAIL Extended DNS Error Code 1 - DNSSEC Bogus . . . . . .   6
       4.1.2.  SERVFAIL Extended DNS Error Code 2 - DNSSEC
               Indeterminate . . . . . . . . . . . . . . . . . . . .   6
       4.1.3.  SERVFAIL Extended DNS Error Code 3 - Signature
               Expired . . . . . . . . . . . . . . . . . . . . . . .   6
       4.1.4.  SERVFAIL Extended DNS Error Code 4 - Signature Not
               Yet Valid . . . . . . . . . . . . . . . . . . . . . .   6
       4.1.5.  SERVFAIL Extended DNS Error Code 5 - Unsupported
               DNSKEY Algorithm  . . . . . . . . . . . . . . . . . .   6
       4.1.6.  SERVFAIL Extended DNS Error Code 6 - Unsupported
               DS Algorithm  . . . . . . . . . . . . . . . . . . . .   6
       4.1.7.  SERVFAIL Extended DNS Error Code 7 - DNSKEY missing . . . . .   6
       4.1.8.  SERVFAIL Extended DNS Error Code 8 - RRSIGs missing . . . . .   6   7
       4.1.9.  SERVFAIL Extended DNS Error Code 9 - No Zone Key Bit
               Set . . .   6
     4.2.  REFUSED(5) extended information codes . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  INFO-CODEs for use with RESPONSE-CODE: REFUSED(5) . . . .   7
       4.2.1.  REFUSED Extended DNS Error Code 1 - Lame  . . . . . . . . . .   7
       4.2.2.  REFUSED Extended DNS Error Code 2 - Prohibited  . . . . . . .   7
     4.3.  INFO-CODEs for use with RESPONSE-CODE: NXDOMAIN(3) extended information codes  . . . . . .  . . .   7
       4.3.1.  NXDOMAIN Extended DNS Error Code 1 - Blocked  . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  new Extended Error Code EDNS Option . . . . . . . . . . .   7
     5.2.  new  New Extended Error Code EDNS Option . . . . . . . . . . .   7
   6.  Open questions  . . . . . . . . . . . . . . . . . . . . . . .   8
   7.
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   8.   9
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   9.  10
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     9.1.  10
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     9.2.  10
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   9  10
   Appendix A.  Changes / Author Notes.  . . . . . . . . . . . . . .   9  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10  11

1.  Introduction and background

   There are many reasons that a DNS query may fail, some of them
   transient, some permanent; some can be resolved by querying another
   server, some are likely best handled by stopping resolution.
   Unfortunately, the error signals that a DNS server can return are
   very limited, and are not very expressive.  This means that
   applications and resolvers often have to "guess" at what the issue is
   - e.g e.g. was the answer was marked REFUSED because of a lame delegation, or
   because of a lame delegation or because the nameserver is still starting up and loading zones?  Is a
   SERVFAIL a DNSSEC validation issue, or is the nameserver experiencing
   a bad hair day?

   A good example of issues that would benefit by additional error
   information is an error are errors caused by a DNSSEC validation issue. issues.  When a
   stub resolver queries a DNSSEC bogus name (using a validating
   resolver), the stub resolver receives only a SERVFAIL in response.
   Unfortunately, SERVFAIL is used to signal many sorts of DNS errors,
   and so the stub resolver simply asks the next configured DNS
   resolver.  The result of trying the next resolver is one of two
   outcomes: either the next resolver also validates, a SERVFAIL is
   returned again, and the user gets an (largely) incomprehensible error
   message; or the next resolver is not a validating resolver, and the
   user is returned a potentially harmful result.

   This document specifies a mechanism to extend (or annotate) DNS
   errors to provide additional information about the cause of the
   error.  This  When properly authenticated, this information can be used by
   the resolver to make a decision regarding whether or not to retry, retry or
   it can be used or by technical users attempting to debug issues.

   Here is a reference to an "external" (non-RFC / draft) thing:
   ([IANA.AS_Numbers]).  And this is a link to an
   ID:[I-D.ietf-sidr-iana-objects].

1.1.  Requirements notation

   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].

2.  Extended Error EDNS0 option format

   This draft uses an EDNS0 ([RFC2671]) option to include extended error
   (ExtError) Extended DNS
   Error (EDE) information in DNS messages.  The option is structured as
   follows:

                                                1   1   1   1   1   1
        0   1   2   3   4   5   6   7   8   9   0   1   2   3   4   5
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   0: |                            OPTION-CODE                        |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   2: |                           OPTION-LENGTH                       |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   4: | R |                          RESERVED                         |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   6: | RESPONSE-CODE |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   8: |             INFO-CODE                         |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   A:
   8: |                             EXTRA-TEXT                        |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

   Field definition details:

   o  OPTION-CODE, 2 octets (defined in [RFC6891]), for ExtError EDE is TBD.
      [RFC Editor: change TBD to the proper code once assigned by IANA.]
   o  OPTION-LENGTH, 2 octets ((defined in [RFC6891]) contains the
      length of the payload (everything after OPTION-LENGTH) in octets
      and should be 4. 4 plus the length of the EXTRA-TEXT section (which
      may be a zero-length string).
   o  RESERVED, 2 octets;  The RETRY flag, 1 bit; the first RETRY bit (R) indicates a flag defined
      for use in this specification.
   o  The remaining RESERVED bits, 15 bits: these bits are reserved for future
      use, potentially as additional flags.

   o  RESPONSE-CODE, 2 octets: this SHOULD  The RESERVED bits MUST be a copy of the RCODE from
      the primary DNS packet.  When including multiple extended error
      EDNS0 records in a response in order
      set to provide additional error
      information, 0 by the RESPONSE-CODE MAY sender and SHOULD be a different RCODE. ignored by the receiver.
   o  RESPONSE-CODE, 4 bits.
   o  INFO-CODE, 2 octets. 12-bits.
   o  A  EXTRA-TEXT, a variable length EXTRA-TEXT length, ASCII encoded, text field holding additional textual
      information.  It that may be zero length when no
      hold additional textual
      information is included.

   Currently the only defined flag is information.

3.  Use of the R flag.

   R - Retry Extended DNS Error option

   The R (or Retry) flag provides Extended DNS Error (EDE) is an EDNS option.  It can be included
   in any response (SERVFAIL, NXDOMAIN, REFUSED, etc) to a hint to the receiver that
      it should retry the query, probably by querying another server.
      If the R bit is set (1), the sender believes that retrying the
      query may provide a successful answer next time; if the R bit is
      clear (0), the sender believes that it should not ask another
      server.

   The remaining bits in the RESERVED field are reserved for future use
   and MUST be set to 0 by the sender and SHOULD be ignored by the
   receiver.

   INFO-CODE: A code point that, when combined with the RCODE from the
   DNS packet, serve as a joint-index into the IANA "Extended DNS
   Errors" registry.

3.  Use of the Extended DNS Error option

   The Extended DNS Error (EDE) is an EDNS option.  It can be included
   in any error response (SERVFAIL, NXDOMAIN, REFUSED, etc) to a query
   that includes an EDNS option.  This document includes a set of
   initial codepoints (and requests query that
   includes an EDNS option.  This document includes a set of initial
   codepoints (and requests to the IANA to add them to the registry),
   but is extensible via the IANA registry to allow additional error and
   information codes to be defined in the future.

   The fields of the Extended DNS Error option are defined further in
   the following sub-sections.

3.1.  The R (Retry) flag

   The R (Retry) flag provides a hint (or suggestion) as to what the receiver may want
   to do with this annotated error.  Specifically, the R (or Retry) flag
   provides a hint to the receiver that it should retry the query to
   another server.  If the R bit is set (1), the sender believes that
   retrying the query may provide a successful answer next time; if the
   R bit is clear (0), the sender believes that the resolver should not
   ask another server.

   The mechanism is specifically designed to be extensible, and so
   implementations may receive EDE codes that it does not understand.
   The R flag allows implementations to make a decision as to what to do
   if it receives a response with an unknown code - retry or drop the
   query.  Note that this flag is only a suggestion suggestion.  Unless a
   protective transport mechanism (like TSIG [RFC2845] or hint. TLS [RFC8094])
   is used, the bit's value could have have been altered by a person-in-
   the-middle.  Receivers can choose to ignore this hint.  See the
   security considerations for additional considerations.

3.2.  The EXTRA-INFO textual RESPONSE-CODE field

   This 4-bit value SHOULD be a copy of the RCODE from the primary DNS
   packet.  Multiple EDNS0/EDE records may be included in the response.
   When including multiple EDNS0/EDE records in a response in order to
   provide additional error information, other RESPONSE-CODEs MAY use a
   different RCODE.

3.3.  The INFO-CODE field

   This 12-bit value provides the additional context for the RESPONSE-
   CODE value.  This combination of the RESPONSE-CODE and the INFO-CODE
   serve as a joint-index into the IANA "Extended DNS Errors" registry.

3.4.  The EXTRA-TEXT field

   The ASCII-encoded, EXTRA-TEXT field may be zero-length, or may hold
   additional information useful to network operators.

4.  Defined Extended DNS Errors

   This document defines some initial EDE codes.  The mechanism is
   intended to be extensible, and additional codepoints will code-points can be
   registered in the "Extended DNS Errors" registry.  This document
   provides suggestions for the R flag, but the originating server may
   ignore these recommendations if it knows better.

   The RESPONSE-CODE and the INFO-CODE from the EDE EDNS option is used
   to serve as a double index into the "Extended DNS Error codes" IANA
   registry, the initial values for which are defined in the following
   sub-sections.

4.1.  INFO-CODEs for use with RESPONSE-CODE: SERVFAIL(2) extended information codes

4.1.1.  SERVFAIL Extended DNS Error Code 1 - DNSSEC Bogus

   The resolver attempted to perform DNSSEC validation, but validation
   ended in the Bogus state.  The R flag should not be set.

4.1.2.  SERVFAIL Extended DNS Error Code 2 - DNSSEC Indeterminate

   The resolver attempted to perform DNSSEC validation, but validation
   ended in the Indeterminate state.  The R flag should not be set.

4.1.3.  SERVFAIL Extended DNS Error Code 3 - Signature Expired

   The resolver attempted to perform DNSSEC validation, but the
   signature was expired.  The R flag should not be set.

4.1.4.  SERVFAIL Extended DNS Error Code 4 - Signature Not Yet Valid

   The resolver attempted to perform DNSSEC validation, but the
   signatures received were not yet valid.  The R flag should not be
   set.

4.1.5.  SERVFAIL Extended DNS Error Code 5 - Unsupported DNSKEY
        Algorithm

   The resolver attempted to perform DNSSEC validation, but a DNSKEY
   RRSET contained only unknown algorithms.  The R flag should not be set.

4.1.6.  SERVFAIL Extended DNS Error Code 6 - Unsupported DS Algorithm

   The resolver attempted to perform DNSSEC validation, but a DS RRSET
   contained only unknown algorithms.  The R flag should not be set.

4.1.7.  SERVFAIL Extended DNS Error Code 7 - DNSKEY missing

   A DS record existed at a parent, but no DNSKEY record could be found
   for the child.  The R flag should not be set.

4.1.8.  SERVFAIL Extended DNS Error Code 8 - RRSIGs missing

   The resolver attempted to perform DNSSEC validation, but no RRSIGs
   could be found for at least one RRset where RRSIGs were expected.

4.1.9.  SERVFAIL Extended DNS Error Code 9 - No Zone Key Bit Set

   The resolver attempted to perform DNSSEC validation, but no Zone Key
   Bit was set in a DNSKEY.

4.2.  INFO-CODEs for use with RESPONSE-CODE: REFUSED(5) extended information codes

4.2.1.  REFUSED Extended DNS Error Code 1 - Lame

   An authoritative resolver that receives a query (with the RD bit
   clear) for a domain for which it is not authoritative SHOULD include
   this EDE code in the REFUSED response.  Implementations should set
   the R flag in this case (another nameserver might not be lame).

4.2.2.  REFUSED Extended DNS Error Code 2 - Prohibited

   An authoritative or recursive resolver that receives a query from an
   "unauthorized" client can annotate its REFUSED message with this
   code.  Examples of "unauthorized" clients are recursive queries from
   IP addresses outside the network, blacklisted IP addresses, local
   policy, etc.

   Implementations SHOULD allow operators to define what to set the R
   flag to in this case.

4.3.  INFO-CODEs for use with RESPONSE-CODE: NXDOMAIN(3) extended information codes

4.3.1.  NXDOMAIN Extended DNS Error Code 1 - Blocked

   The resolver attempted to perfom a DNS query but the domain is
   blacklisted due to a security policy.  The R flag should not be set.

5.  IANA Considerations

   [This section under construction, beware. ]

5.1.  new Extended Error Code EDNS Option

   This document defines a new EDNS(0) option, entitled "Extended DNS
   Error", assigned a value of TBD1 from the "DNS EDNS0 Option Codes
   (OPT)" registry [to be removed upon publication:
   [http://www.iana.org/assignments/dns-parameters/dns-
   parameters.xhtml#dns-parameters-11]
   Value  Name                 Status    Reference
   -----  ----------------     ------    ------------------
    TBD   Extended DNS Error    TBD       [ This document ]

5.2.  new  New Extended Error Code EDNS Option

   This document defines a new double-index IANA registry table, where
   the first index value is the RCODE value and the second index value
   is the INFO-CODE from the Extended DNS Error EDNS option defined in
   this document.  The IANA is requested to create and maintain this
   "Extended DNS Error codes" registry.  The codepoint space for each
   RCODE
   INFO-CODE index is to be broken into 3 ranges:

   o  1  0 - 16384: 3583: Specification required.
   o  16385  3584 - 65000: 3839: First Come First Served Served.
   o  65000  3840 - 65534: 4095: Experimental / Private use

   The codepoints 0, 65535 are reserved.

   A starting table, set of entries, based on the contents of this document, is
   as follows:

| RCODE       | EDE-INFO-CODE           | Meaning                                     | Ref                                      |
|-------------+-------------------------+---------------------------------------------+------------------------------------------|
| SERVFAIL(2) | DNSSEC_BOGUS(1)         |

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  1
   Purpose:  DNSSEC Validation resulted in Bogus         | section <xref target="errbogus" />         |
| SERVFAIL(2) | DNSSEC_INDETERMINATE(2) |
   Reference:  Section 4.1.1

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  2
   Purpose:  DNSSEC Validation resulted in Indeterminate | section <xref target="errindeterminate" /> |

[incomplete]

6.  Open questions
   Reference:  Section 4.1.2

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  3
   Purpose:  Signature Expired
   Reference:  Section 4.1.3

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  4
   Purpose:  Signature Not Yet Valid
   Reference:  Section 4.1.4

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  5
   Purpose:  Unsupported DNSKEY
   Reference:  Section 4.1.5

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  6
   Purpose:  Unsupported DS Algorithm
   Reference:  Section 4.1.6

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  7
   Purpose:  DNSKEY missing
   Reference:  Section 4.1.7

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  8
   Purpose:  RRSIGs missing
   Reference:  Section 4.1.8

   RESPONSE-CODE:  2 (SERVFAIL)
   INFO-CODE:  9
   Purpose:  No Zone Key Bit Set
   Reference:  Section 4.1.9

   RESPONSE-CODE:  3 (NXDOMAIN)
   INFO-CODE:  1  Can this be included in *any* response or only responses to
      requests that included an EDNS option?  Resolvers are supposed to
      ignore additional.  EDNS capable ones are supposed to simply
      ignore unknown options.  I know the spec says you can only include
      EDNS0 in a response if in a request -- it is time to reevaluate
      this?

7.
   Purpose:  Blocked
   Reference:  Section 4.3.1

   RESPONSE-CODE:  5 (REFUSED)
   INFO-CODE:  1
   Purpose:  Lame
   Reference:  Section 4.2.1

   RESPONSE-CODE:  5 (REFUSED)
   INFO-CODE:  2
   Purpose:  Prohibited
   Reference:  Section 4.2.2

6.  Security Considerations

   Though DNSSEC is being deployed - continues to be deployed, unfortunately a significant
   number of clients (~11% according to [GeoffValidation]), when receiving [GeoffValidation]) that receive
   a SERVFAIL from a validating resolver because of a DNSSEC validaion
   issue will simply ask the next (non-validating) (potentially non-validating) resolver
   in their list, and thus don't get any of the protections which DNSSEC
   should provide.  This is very similar to a kid asking his mother if
   he can have another cookie.  When the mother says "No, it will ruin
   your dinner!", going off and asking his (more permissive) father and
   getting a "Yes, sure, have a cookie!".

8.

   This information is unauthenticated information, and an attacker (e.g
   MITM or malicious recursive server) could insert an extended error
   response into already untrusted data -- ideally clients and resolvers
   would not trust any unauthenticated information, but until we live in
   an era where all DNS answers are authenticated via DNSSEC or other
   mechanisms, there are some tradeoffs.  As an example, an attacker who
   is able to insert the DNSSEC Bogus Extended Error into a packet could
   instead simply reply with a fictitious address (A or AAAA) record.
   The R bit hint and extended error information are informational -
   implementations can choose how much to trust this information and
   validating resolvers / stubs may choose to put a different weight on
   it.

7.  Acknowledgements

   The authors wish to thank Geoff Huston and Joe Abley, Mark Andrews, Peter DeVries,
   Peter van Dijk, Donald Eastlake, Bob Harold, Evan Hunt, Geoff Huston,
   Shane Kerr, Edward Lewis, Carlos M.  Martinez, Peter DeVries, George Michelson, Mark Andrews, Petr
   Spacek, Ondrej Sury,
   Edward Lewis, Paul Vixie, Shane Kerr, Loganaden Velvindron. Velvindron, and Paul Vixie.  They also
   vaguely remember discussing this with a number of people over the
   years, but have forgotten who all they were -- if you were one of
   them, and are not listed, please let us know and we'll acknowledge
   you.

   I also want to thank the band "Infected Mushroom" for providing a
   good background soundtrack (and to see if I can get away with this!)
   Another author would like to thank the band "Mushroom Infectors".
   This was funny at the time we wrote it, but I cannot remember why...

   We would like to especially thank Peter van Dijk, who sent GitHub
   pull requests.

9.

8.  References

9.1.

8.1.  Normative References

   [IANA.AS_Numbers]
              IANA, "Autonomous System (AS) Numbers",
              <http://www.iana.org/assignments/as-numbers>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

9.2. <https://www.rfc-
              editor.org/info/rfc2119>.

8.2.  Informative References

   [GeoffValidation]
              IANA, "A quick review of DNSSEC Validation in today's
              Internet", June 2016, <http://www.potaroo.net/
              presentations/2016-06-27-dnssec.pdf>.

   [I-D.ietf-sidr-iana-objects]
              Manderson,

   [RFC2845]  Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B.
              Wellington, "Secret Key Transaction Authentication for DNS
              (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000,
              <https://www.rfc-editor.org/info/rfc2845>.

   [RFC8094]  Reddy, T., Vegoda, L., Wing, D., and S. Kent, "RPKI Objects
              issued by IANA", draft-ietf-sidr-iana-objects-03 (work in
              progress), May 2011. P. Patil, "DNS over Datagram
              Transport Layer Security (DTLS)", RFC 8094,
              DOI 10.17487/RFC8094, February 2017, <https://www.rfc-
              editor.org/info/rfc8094>.

Appendix A.  Changes / Author Notes.

   [RFC Editor: Please remove this section before publication ]

   From -00 to -01:

   o  Address comments from IETF meeting.
   o  document copying the response code
   o  mention zero length fields are ok
   o  clarify lookup procedure
   o  mention that table isn't done

   From -03 to -IETF 00:

   o  Renamed to draft-ietf-dnsop-extended-error

   From -02 to -03:

   o  Added David Lawrence -- I somehow missed that in last version.

   From -00 to -01;

   o  Fixed up some of the text, minor clarifications.

Authors' Addresses

   Warren Kumari
   Google
   1600 Amphitheatre Parkway
   Mountain View, CA  94043
   US

   Email: warren@kumari.net

   Evan Hunt
   ISC
   950 Charter St
   Redwood City, CA  94063
   US

   Email: each@isc.org
   Roy Arends
   ICANN

   Email: roy.arends@icann.org

   Wes Hardaker
   USC/ISI
   P.O. Box 382
   Davis, CA  95617
   US

   Email: ietf@hardakers.net

   David C Lawrence
   Oracle + Dyn
   150 Dow St
   Manchester, NH  03101
   US

   Email: tale@dd.org