Internet DRAFT - draft-ietf-lemonade-burl
draft-ietf-lemonade-burl
Network Working Group C. Newman
Internet-Draft Sun Microsystems
Updates: 3463 (if approved) November 10, 2005
Expires: May 14, 2006
Message Submission BURL Extension
draft-ietf-lemonade-burl-04.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
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.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on May 14, 2006.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
The submission profile of Simple Mail Transfer Protocol (SMTP)
provides a standard way for an email client to submit a complete
message for delivery. This specification extends the submission
profile by adding a new BURL command which can be used to fetch
submission data from an Internet Message Access Protocol (IMAP)
server. This permits a mail client to inject content from an IMAP
server into the SMTP infrastructure without downloading it to the
client and uploading it back to the server.
Newman Expires May 14, 2006 [Page 1]
Internet-Draft Message Submission BURL Extension November 2005
Table of Contents
1. Conventions Used in this Document . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. BURL Submission Extension . . . . . . . . . . . . . . . . . . 3
3.1 SMTP Submission Extension Registration . . . . . . . . . . 3
3.2 BURL Transaction . . . . . . . . . . . . . . . . . . . . . 4
3.3 The BURL IMAP Option . . . . . . . . . . . . . . . . . . . 4
3.4 Examples . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.5 Formal Syntax . . . . . . . . . . . . . . . . . . . . . . 7
4. 8-bit and Binary . . . . . . . . . . . . . . . . . . . . . . . 7
5. Updates to RFC 3463 . . . . . . . . . . . . . . . . . . . . . 8
6. Response Codes . . . . . . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1 Normative References . . . . . . . . . . . . . . . . . . . 11
9.2 Informative References . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 13
A. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
Intellectual Property and Copyright Statements . . . . . . . . 14
Newman Expires May 14, 2006 [Page 2]
Internet-Draft Message Submission BURL Extension November 2005
1. Conventions Used in this Document
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"
in this document are to be interpreted as defined in "Key words for
use in RFCs to Indicate Requirement Levels" [RFC2119].
The formal syntax use the Augmented Backus-Naur Form (ABNF) [RFC4234]
notation including the core rules defined in Appendix B of RFC 4234.
2. Introduction
This specification defines an extension to the standard Message
Submission [I-D.gellens-submit-bis] protocol to permit data to be
fetched from an IMAP server at message submission time. This MAY be
used in conjunction with the CHUNKING [RFC3030] mechanism so that
chunks of the message can come from an external IMAP server. This
provides the ability to forward an email message without first
downloading it to the client.
3. BURL Submission Extension
This section defines the BURL submission extension.
3.1 SMTP Submission Extension Registration
1. The name of this submission extension is "BURL". This extends
the Message Submission protocol on port 587 and MUST NOT be
advertised by a regular SMTP [RFC2821] server on port 25 that
acts as a relay for incoming mail from other SMTP relays.
2. The EHLO keyword value associated with the extension is "BURL".
3. The BURL EHLO keyword will have zero or more arguments. The only
argument defined at this time is the "imap" argument, which MUST
be present in order to use IMAP URLs with BURL. Clients MUST
ignore other arguments after the BURL EHLO keyword unless they
are defined by a subsequent IETF standards track specification.
The arguments which appear after the BURL EHLO keyword may change
subsequent to the use of SMTP AUTH [RFC2554], so a server which
advertises BURL with no arguments prior to authentication
indicates that BURL is supported but authentication is required
to use it.
4. This extension adds the BURL SMTP verb. This verb is used as a
replacement for the DATA command and is only permitted during a
mail transaction after at least one successful RCPT TO.
Newman Expires May 14, 2006 [Page 3]
Internet-Draft Message Submission BURL Extension November 2005
3.2 BURL Transaction
A simple BURL transaction will consist of MAIL FROM, one or more RCPT
TO headers and a BURL command with the "LAST" tag. The BURL command
will include an IMAP URL pointing to a fully formed message ready for
injection into the SMTP infrastructure. If PIPELINING [RFC2920] is
advertised, the client MAY send the entire transaction in one round
trip. If no valid RCPT TO address is supplied, the BURL command will
simply fail and no resolution of the BURL URL argument will be
performed. If at least one valid RCPT TO address is supplied, then
the BURL URL argument will be resolved before the server responds to
the command.
A more sophisticated BURL transaction MAY occur when the server also
advertises CHUNKING [RFC3030]. In this case, the BURL and BDAT
commands may be interleaved until one of them terminates the
transaction with the "LAST" argument. If PIPELINING [RFC2920] is
also advertised, then the client may pipeline the entire transaction
in one round-trip. However, it MUST wait for the results of the
"LAST" BDAT or BURL command prior to initiating a new transaction.
The BURL command directs the server to fetch the data object to which
the URL refers and include it in the message. If the URL fetch
fails, the server will fail the entire transaction.
3.3 The BURL IMAP Option
When "imap" is present in the space-separated list of arguments
following the BURL EHLO keyword, that indicates the BURL command
supports the URLAUTH [I-D.ietf-lemonade-urlauth] extended form of
IMAP URLs [RFC2192] and the submit server is configured with the
necessary credentials to resolve "urlauth=submit+" IMAP URLs for the
submit server's domain.
Subsequent to a successful SMTP AUTH command, the submission server
MAY indicate a pre-arranged trust relationship with a specific IMAP
server by including a BURL EHLO keyword argument of the form
"imap://imap.example.com". In this case, the submission server will
permit a regular IMAP URL referring to messages or parts of messages
on imap.example.com which the user who authenticated to the submit
server can access. Note that this form does not imply the submit
server supports URLAUTH URLs, the submit server must advertise both
"imap" and "imap://imap.example.com" to indicate support for both
extended and non-extended URL forms.
When the submit server connects to the IMAP server, it acts as an
IMAP client; and thus is subject to both the mandatory-to-implement
IMAP capabilities in section 6.1.1 of RFC 3501, and the security
Newman Expires May 14, 2006 [Page 4]
Internet-Draft Message Submission BURL Extension November 2005
considerations in section 11 of RFC 3501. Specifically, this
requires that the submit server implement a configuration that uses
STARTTLS followed by SASL PLAIN [I-D.ietf-sasl-plain] to authenticate
to the IMAP server.
When the submit server resolves a URLAUTH IMAP URL, it uses submit
server credentials when authenticating to the IMAP server. The
authentication identity and password used for submit credentials MUST
be configurable. The string "submit" is suggested as a default value
for the authentication identity, with no default for the password.
Typically, the authorization identity is empty in this case; thus the
IMAP server will derive the authorization identity from the
authentication identity.
When the submit server resolves a regular IMAP URL, it uses the
submit client's authorization identity when authenticating to the
IMAP server. If both the submit client and the submit server's
embedded IMAP client use SASL PLAIN (or the equivalent), the submit
server SHOULD forward the client's credentials if and only if the
submit server knows that the IMAP server is in the same
administrative domain. If the submit server supports SASL mechanisms
other than PLAIN, it MUST implement a configuration in which the
submit server's embedded IMAP client uses STARTTLS and SASL PLAIN
with the submit server's authentication identity and password (for
the respective IMAP server) and the submit client's authorization
identity.
3.4 Examples
In examples, "C:" and "S:" indicate lines sent by the client and
server respectively. If a single "C:" or "S:" label applies to
multiple lines, then the line breaks between those lines are for
editorial clarity only and are not part of the actual protocol
exchange.
Two successful submissions (without and with pipelining) follow:
Newman Expires May 14, 2006 [Page 5]
Internet-Draft Message Submission BURL Extension November 2005
<SSL/TLS encryption layer negotiated>
C: EHLO potter.example.com
S: 250-owlry.example.com
S: 250-8BITMIME
S: 250-BURL imap
S: 250-AUTH PLAIN
S: 250-DSN
S: 250 ENHANCEDSTATUSCODES
C: AUTH PLAIN aGFycnkAaGFycnkAYWNjaW8=
S: 235 2.7.0 PLAIN authentication successful.
C: MAIL FROM:<harry@gryffindor.example.com>
S: 250 2.5.0 Address Ok.
C: RCPT TO:<ron@gryffindor.example.com>
S: 250 2.1.5 ron@gryffindor.example.com OK.
C: BURL imap://harry@gryffindor.example.com/outbox
;uidvalidity=1078863300/;uid=25;urlauth=submit+harry
:internal:91354a473744909de610943775f92038 LAST
S: 250 2.5.0 Ok.
<SSL/TLS encryption layer negotiated>
C: EHLO potter.example.com
S: 250-owlry.example.com
S: 250-8BITMIME
S: 250-PIPELINING
S: 250-BURL imap
S: 250-AUTH PLAIN
S: 250-DSN
S: 250 ENHANCEDSTATUSCODES
C: AUTH PLAIN aGFycnkAaGFycnkAYWNjaW8=
C: MAIL FROM:<harry@gryffindor.example.com>
C: RCPT TO:<ron@gryffindor.example.com>
C: BURL imap://harry@gryffindor.example.com/outbox
;uidvalidity=1078863300/;uid=25;urlauth=submit+harry
:internal:91354a473744909de610943775f92038 LAST
S: 235 2.7.0 PLAIN authentication successful.
S: 250 2.5.0 Address Ok.
S: 250 2.1.5 ron@gryffindor.example.com OK.
S: 250 2.5.0 Ok.
Note that PIPELINING of the AUTH command is only permitted if the
selected mechanism can be completed in one round trip, a client
initial response is provided, and no SASL security layer is
negotiated. This is possible for PLAIN and EXTERNAL, but not for
most other SASL mechanisms.
Newman Expires May 14, 2006 [Page 6]
Internet-Draft Message Submission BURL Extension November 2005
Some example failure cases:
C: MAIL FROM:<harry@gryffindor.example.com>
C: RCPT TO:<malfoy@slitherin.example.com>
C: BURL imap://harry@gryffindor.example.com/outbox
;uidvalidity=1078863300/;uid=25;urlauth=submit+harry
:internal:91354a473744909de610943775f92038 LAST
S: 250 2.5.0 Address Ok.
S: 550 5.7.1 Relaying not allowed: malfoy@slitherin.example.com
S: 554 5.5.0 No recipients have been specified.
C: MAIL FROM:<harry@gryffindor.example.com>
C: RCPT TO:<ron@gryffindor.example.com>
C: BURL imap://harry@gryffindor.example.com/outbox
;uidvalidity=1078863300/;uid=25;urlauth=submit+harry
:internal:71354a473744909de610943775f92038 LAST
S: 250 2.5.0 Address Ok.
S: 250 2.1.5 ron@gryffindor.example.com OK.
S: 554 5.7.0 IMAP URL authorization failed
3.5 Formal Syntax
The following syntax specification inherits ABNF [RFC4234] and
Uniform Resource Identifiers [RFC3986].
burl-param = "imap" / ("imap://" authority)
; parameter to BURL EHLO keyword
burl-cmd = "BURL" SP absolute-URI [SP end-marker] CRLF
end-marker = "LAST"
4. 8-bit and Binary
A submit server which advertises BURL MUST also advertise 8BITMIME
[RFC1652] and perform the down conversion described in that
specification on the resulting complete message if 8-bit data is
received with the BURL command and passed to a 7-bit server. If the
URL argument to BURL refers to binary data, then the submit server
MAY refuse the command or down convert as described in Binary SMTP
[RFC3030].
The Submit server MAY refuse to accept a BURL command or combination
of BURL and BDAT commands which result in un-encoded 8-bit data in
mail or MIME [RFC2045] headers. Alternatively, the server MAY accept
such data and down convert to MIME header encoding [RFC2047].
Newman Expires May 14, 2006 [Page 7]
Internet-Draft Message Submission BURL Extension November 2005
5. Updates to RFC 3463
SMTP or Submit servers which advertise ENHANCEDSTATUSCODES [RFC2034]
use enhanced status codes defined in RFC 3463 [RFC3463]. The BURL
extension introduces new error cases which that RFC did not consider.
The following additional enhanced status codes are defined by this
specification:
X.6.6 Message content not available
The message content could not be fetched from a remote system.
This may be useful as a permanent or persistent temporary
notification.
X.7.8 Trust relationship required
The submission server requires a configured trust relationship
with a third-party server in order to access the message content.
6. Response Codes
This section includes example response codes to the BURL command.
Other text may be used with the same response codes. This list is
not exhaustive and BURL clients MUST tolerate any valid SMTP response
code. Most of these examples include the appropriate enhanced status
code [RFC3463].
554 5.5.0 No recipients have been specified
This response code occurs when BURL is used (for example, with
PIPELINING) and all RCPT TOs failed.
503 5.5.0 Valid RCPT TO required before BURL
This response code is an alternative to the previous one when BURL
is used (for example, with PIPELINING) and all RCPT TOs failed.
554 5.6.3 Conversion required but not supported
This response code occurs when the URL points to binary data and
the implementation does not support down conversion to base64.
This can also be used if the URL points to message data with 8-bit
content in headers and the server does not down convert such
content.
Newman Expires May 14, 2006 [Page 8]
Internet-Draft Message Submission BURL Extension November 2005
554 5.3.4 Message too big for system
The message (subsequent to URL resolution) is larger than the per-
message size limit for this server.
554 5.7.8 URL resolution requires trust relationship
The submit server does not have a trust relationship with the IMAP
server specified in the URL argument to BURL.
552 5.2.2 Mailbox full
The recipient is local, the submit server supports direct delivery
and the recipient has exceeded his quota and any grace period for
delivery attempts.
554 5.6.6 IMAP URL resolution failed
The IMAP FETCHURL command returned an error or no data.
354 Waiting for additional BURL or BDAT commands
A BURL command without the "LAST" modifier was sent. The URL for
this BURL command was successfully resolved, but the content will
not necessarily be committed to persistent storage until the rest
of the message content is collected. For example, a Unix server
may have written the content to a queue file buffer, but not yet
performed an fsync() operation. If the server loses power, the
content can still be lost.
451 4.4.1 IMAP server unavailable
The connection to the IMAP server to resolve the URL failed.
250 2.5.0 Ok.
The URL was successfully resolved and the complete message data
has been committed to persistent storage.
250 2.6.4 MIME header conversion with loss performed
The URL pointed to message data which included mail or MIME
headers with 8-bit data. This data was converted to MIME header
encoding [RFC2047] but the submit server may not have correctly
guessed the unlabeled character set.
Newman Expires May 14, 2006 [Page 9]
Internet-Draft Message Submission BURL Extension November 2005
7. IANA Considerations
When this is published as an RFC, the "BURL" SMTP extension as
described in Section 3 will be registered. This registration will be
marked for use by message submission [I-D.gellens-submit-bis] only in
the registry.
8. Security Considerations
Modern SMTP submission servers often include content-based security
and denial-of-service defense mechanisms such as virus filtering,
size limits, server-generated signatures, spam filtering, etc.
Implementations of BURL should fetch the URL content prior to
application of such content-based mechanisms in order to preserve
their function.
Clients which generate unsolicited bulk email or email with viruses
could use this mechanism to compensate for a slow link between the
client and submit server. In particular, this mechanism would make
it feasible for a programmable cell phone or other device on a slow
link to become a significant source of unsolicited bulk email and/or
viruses. This makes it more important for submit server vendors
implementing BURL to have auditing and/or defenses against such
denial-of-service attacks including mandatory authentication, logging
which associates unique client identifiers with mail transactions,
limits on re-use of the same IMAP URL, rate limits, recipient count
limits and content filters.
Transfer of the URLAUTH [I-D.ietf-lemonade-urlauth] form of IMAP URLs
in the clear can expose the authorization token to network
eavesdroppers. Implementations which support such URLs can address
this issue by using a strong confidentiality protection mechanism.
For example, the SMTP STARTTLS [RFC3207] and the IMAP STARTTLS
[RFC3501] extensions in combination with a configuration setting
which requires their use with such IMAP URLs would address this
concern.
Use of a pre-arranged trust relationship between a submit server and
a specific IMAP server introduces security considerations: a
compromise of the submit server should not automatically compromise
all accounts on the IMAP server so trust relationships involving
super-user proxy credentials are strongly discouraged. A system
which requires the submit server to authenticate to the IMAP server
with submit credentials and subsequently requires a URLAUTH URL to
fetch any content addresses this concern. A trusted third party
model for proxy credentials such as that provided by Kerberos5
[RFC1510] would also suffice.
Newman Expires May 14, 2006 [Page 10]
Internet-Draft Message Submission BURL Extension November 2005
When a client uses SMTP STARTTLS to send a BURL command which
references non-public information there is a user expectation that
the entire message content will be treated confidentially. To
address this expectation, the message submission server SHOULD use
STARTTLS or a mechanism providing equivalent data confidentiality
when fetching the content referenced by that URL.
A legitimate user of a submit server may try to compromise other
accounts on the server by providing an IMAP URLAUTH URL which points
to a server under that user's control which is designed to undermine
the security of the submit server. For this reason, the IMAP client
code which the submit server uses must be robust with respect to
arbitrary input sizes (including large IMAP literals) and arbitrary
delays from the IMAP server. Requiring a pre-arranged trust
relationship between a submit server and the IMAP server also
addresses this concern.
An authorized user of the submit server could set up a fraudulent
IMAP server and pass a URL for that server to the submit server. The
submit server might then contact the fraudulent IMAP server to
authenticate with submit credentials and fetch content. There are
several ways to mitigate this potential attack. A submit server
which only uses submit credentials with a fixed set of trusted IMAP
servers will not be vulnerable to exposure of those credentials. A
submit server can treat the IMAP server as untrusted and include
defenses for buffer overflows, denial-of-service slowdowns and other
potential attacks. And finally, because authentication is required
to use BURL, it is possible to keep a secure audit trail and use that
to detect and punish the offending party.
9. References
9.1 Normative References
[RFC1652] Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
Crocker, "SMTP Service Extension for 8bit-MIMEtransport",
RFC 1652, July 1994.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2192] Newman, C., "IMAP URL Scheme", RFC 2192, September 1997.
[RFC2222] Myers, J., "Simple Authentication and Security Layer
(SASL)", RFC 2222, October 1997.
[RFC2554] Myers, J., "SMTP Service Extension for Authentication",
RFC 2554, March 1999.
Newman Expires May 14, 2006 [Page 11]
Internet-Draft Message Submission BURL Extension November 2005
[RFC2821] Klensin, J., "Simple Mail Transfer Protocol", RFC 2821,
April 2001.
[RFC3207] Hoffman, P., "SMTP Service Extension for Secure SMTP over
Transport Layer Security", RFC 3207, February 2002.
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, March 2003.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC4234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 4234, October 2005.
[I-D.ietf-lemonade-urlauth]
Crispin, M., "Internet Message Access Protocol (IMAP) -
URLAUTH Extension", draft-ietf-lemonade-urlauth-08 (work
in progress), October 2005.
[I-D.gellens-submit-bis]
Gellens, R. and J. Klensin, "Message Submission for Mail",
draft-gellens-submit-bis-02 (work in progress),
April 2005.
9.2 Informative References
[RFC1510] Kohl, J. and B. Neuman, "The Kerberos Network
Authentication Service (V5)", RFC 1510, September 1993.
[RFC2034] Freed, N., "SMTP Service Extension for Returning Enhanced
Error Codes", RFC 2034, October 1996.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII Text",
RFC 2047, November 1996.
[RFC2920] Freed, N., "SMTP Service Extension for Command
Pipelining", STD 60, RFC 2920, September 2000.
[RFC3030] Vaudreuil, G., "SMTP Service Extensions for Transmission
of Large and Binary MIME Messages", RFC 3030,
December 2000.
Newman Expires May 14, 2006 [Page 12]
Internet-Draft Message Submission BURL Extension November 2005
[RFC3463] Vaudreuil, G., "Enhanced Mail System Status Codes",
RFC 3463, January 2003.
[I-D.ietf-sasl-plain]
Zeilenga, K., "The Plain SASL Mechanism",
draft-ietf-sasl-plain-08 (work in progress), March 2005.
Author's Address
Chris Newman
Sun Microsystems
3401 Centrelake Dr., Suite 410
Ontario, CA 91761
US
Email: chris.newman@sun.com
Appendix A. Acknowledgments
This document is a product of the lemonade WG. Many thanks are due
to the all participants of that working group for their input. Mark
Crispin was instrumental in the conception of this mechanism. Thanks
to Randall Gellens, Alexey Melnikov, Sam Hartman, Ned Freed and Mark
Crispin for review comments on the document. Thanks to Ted Hardie,
Randall Gellens, Mark Crispin, Pete Resnick and Greg Vaudreuil for
extremely interesting debates comparing this proposal and
alternatives. Thanks to the lemonade WG chairs Eric Burger and Glenn
Parsons for concluding the debate at the correct time and making sure
this document got completed.
Newman Expires May 14, 2006 [Page 13]
Internet-Draft Message Submission BURL Extension November 2005
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM 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.
Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
Newman Expires May 14, 2006 [Page 14]
