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Versions: (draft-gont-tsvwg-source-quench) 00 01 02 03 04 05 06 RFC 6633

Transport Area Working Group                                     F. Gont
(tsvwg)                                                          UTN/FRH
Internet-Draft                                          January 27, 2011
Updates: 792, 1122, 1812
(if approved)
Intended status: Standards Track
Expires: July 31, 2011


               Deprecation of ICMP Source Quench messages
                 draft-ietf-tsvwg-source-quench-00.txt

Abstract

   This document formally deprecates the use of ICMP Source Quench
   messages by transport protocols, formally updating RFC 792, RFC 1122,
   and RFC 1812.  Additionally, it requests that the status of RFC 1016
   be changed to "Historic".

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 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 July 31, 2011.

Copyright Notice

   Copyright (c) 2011 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
   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
   include Simplified BSD License text as described in Section 4.e of



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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  ICMP Source Quench messages . . . . . . . . . . . . . . . . . . 3
   3.  Updating RFC 1122 . . . . . . . . . . . . . . . . . . . . . . . 4
   4.  Updating RFC 1812 . . . . . . . . . . . . . . . . . . . . . . . 4
   5.  General Advice to Transport Protocols . . . . . . . . . . . . . 4
   6.  Changing the status of RFC 1016 Historic  . . . . . . . . . . . 4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     10.1.  Normative References . . . . . . . . . . . . . . . . . . . 5
     10.2.  Informative References . . . . . . . . . . . . . . . . . . 6
   Appendix A.  Survey of support of ICMP Source Quench in some
                popular TCP/IP implementations . . . . . . . . . . . . 6
   Appendix B.  Changes from previous versions of the draft (to
                be removed by the RFC Editor before publishing
                this document as an RFC) . . . . . . . . . . . . . . . 6
     B.1.   Changes from draft-gont-tsvwg-source-quench-01 . . . . . . 7
     B.2.   Changes from draft-gont-tsvwg-source-quench-00 . . . . . . 7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 7

























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1.  Introduction

   The ICMP specification [RFC0792] defined the ICMPv4 Source Quench
   message (type 4, code 0), which was meant as a mechanism for
   congestion control.  ICMP Source Quench has been known to be an
   ineffective (and unfair) antidote for congestion, and generation of
   ICMP Source Quench messages by routers has been formally deprecated
   by [RFC1812] since 1995.  However, reaction to ICMP Source Quench
   messages in transport protocols has never been formally deprecated.

   This document formally deprecates reaction to ICMP Source Quench
   messages by transport protocols such as TCP, formally updating
   [RFC0792], [RFC1122], and [RFC1812].  Additionally, it requests that
   the status of [RFC1016] be changed to "Historic".

   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 RFC 2119 [RFC2119].


2.  ICMP Source Quench messages

   The ICMP specification [RFC0792] defined the ICMP Source Quench
   message (type 4, code 0), which was meant to provide a mechanism for
   congestion control.  The Host Requirements RFC [RFC1122] stated in
   Section 4.2.3.9 that hosts MUST react to ICMP Source Quench messages
   by slowing transmission on the connection, and further added that the
   RECOMMENDED procedure was to put the corresponding connection in the
   slow-start phase of TCP's congestion control algorithm [RFC5681].

   [RFC1812] noted that research suggested that ICMP Source Quench was
   an ineffective (and unfair) antidote for congestion, and formally
   deprecated the generation of ICMP Source Quench messages by routers,
   stating that routers SHOULD NOT send ICMP Source Quench messages in
   response to congestion.

   [RFC5927] discussed the use of ICMP Source Quench messages for
   performing "blind throughput-reduction" attacks, and noted that most
   TCP implementations silently ignore ICMP Source Quench messages.

   We note that TCP implements its own congestion control mechanisms
   [RFC5681] [RFC3168], that do not depend on ICMP Source Quench
   messages.








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      It is interesting to note that ICMPv6 [RFC4443] does not specify a
      "Source Quench" message.


3.  Updating RFC 1122

   This document hereby updates Section 3.2.2.3 of [RFC1122] as follows:

      A host SHOULD NOT send ICMP Source Quench messages.

      If a Source Quench message is received, the IP layer MAY silently
      discard it.

   Section 4.2.3.9 of [RFC1122] is updated as follows:

      TCP SHOULD silently discard any received ICMP Source Quench
      messages.


4.  Updating RFC 1812

   This document hereby updates Section 4.3.3.3 of [RFC1812] as follows:

      A router SHOULD ignore any ICMP Source Quench messages it
      receives.


5.  General Advice to Transport Protocols

   If a Source Quench message is received by a transport-protocol
   instance (e.g., a TCP connection), it SHOULD be silently ignored.


6.  Changing the status of RFC 1016 Historic

   This document requests the RFC Editor to change the status of
   [RFC1016] to "Historic".


7.  Security Considerations

   ICMP Source Quench messages could be leveraged for performing blind
   throughput-reduction attacks against TCP and similar protocols.  This
   attack vector, along with possible countermeasures, have been
   discussed in great detail in [RFC5927] and [CPNI-TCP].  However, as
   noted in [RFC5927] and [CPNI-TCP], virtually all current versions of
   popular TCP implementations already silently ignore ICMP Source
   Quench messages.



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   Silently ignoring ICMP Source Quench messages, as specified in this
   document, eliminates the aforementioned attack vector.

   If deemed necessary, ICMP Source Quench messages could be filtered at
   firewalls.


8.  IANA Considerations

   This document has no actions for IANA.  The RFC-Editor can remove
   this section before publication of this document as an RFC.


9.  Acknowledgements

   The author of this document would like to thank (in alphabetical
   order) Fred Baker, David Black, Scott Bradner, James Carlson, Antonio
   De Simone, Gorry Fairhurst, Alfred Hoenes, Mahesh Jethanandani, Dan
   Wing, and Andrew Yourtchenko, for providing valuable feedback on
   earlier versions of this document.

   This document has benefited from discussions within the TCPM Working
   Group while working on [RFC5927].


10.  References

10.1.  Normative References

   [RFC0792]  Postel, J., "Internet Control Message Protocol", STD 5,
              RFC 792, September 1981.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, September 1981.

   [RFC1016]  Prue, W. and J. Postel, "Something a host could do with
              source quench: The Source Quench Introduced Delay
              (SQuID)", RFC 1016, July 1987.

   [RFC1122]  Braden, R., "Requirements for Internet Hosts -
              Communication Layers", STD 3, RFC 1122, October 1989.

   [RFC1812]  Baker, F., "Requirements for IP Version 4 Routers",
              RFC 1812, June 1995.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.




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   [RFC3168]  Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
              of Explicit Congestion Notification (ECN) to IP",
              RFC 3168, September 2001.

   [RFC5681]  Allman, M., Paxson, V., and E. Blanton, "TCP Congestion
              Control", RFC 5681, September 2009.

10.2.  Informative References

   [CPNI-TCP]
              CPNI, "Security Assessment of the Transmission Control
              Protocol (TCP)", 2009, <http://www.cpni.gov.uk/Docs/
              tn-03-09-security-assessment-TCP.pdf>.

   [FreeBSD]  The FreeBSD Project, "http://www.freebsd.org".

   [Linux]    The Linux Project, "http://www.kernel.org".

   [NetBSD]   The NetBSD Project, "http://www.netbsd.org".

   [OpenBSD]  The OpenBSD Project, "http://www.openbsd.org".

   [OpenSolaris]
              OpenSolaris, "http://www.opensolaris.org".

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, "Internet Control
              Message Protocol (ICMPv6) for the Internet Protocol
              Version 6 (IPv6) Specification", RFC 4443, March 2006.

   [RFC5927]  Gont, F., "ICMP Attacks against TCP", RFC 5927, July 2010.


Appendix A.  Survey of support of ICMP Source Quench in some popular
             TCP/IP implementations

   A large number of implementations completely ignore ICMP Source
   Quench messages meant for TCP connections.  This behavior has been
   implemented in, at least, Linux [Linux] since 2004, and in FreeBSD
   [FreeBSD], NetBSD [NetBSD], OpenBSD [OpenBSD], and Solaris 10 since
   2005.  Additionally, OpenSolaris [OpenSolaris] has always shipped
   with support for ICMP Source Quench messages disabled.


Appendix B.  Changes from previous versions of the draft (to be removed
             by the RFC Editor before publishing this document as an
             RFC)





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B.1.  Changes from draft-gont-tsvwg-source-quench-01

   o  Addresses nits and editorial chagnes suggested by Gorry Fairhurst.

   o  Added the status of Solaris and OpenSolaris to Appendix A.

   o  Document resubmitted as draft-ietf.

B.2.  Changes from draft-gont-tsvwg-source-quench-00

   o  This revision reflects the recent discussion about ICMP Source
      Quench messages on the tsvwg mailing-list.  A detailed list of the
      changes is available at:
      http://www.ietf.org/mail-archive/web/tsvwg/current/msg10407.html


Author's Address

   Fernando Gont
   Universidad Tecnologica Nacional / Facultad Regional Haedo
   Evaristo Carriego 2644
   Haedo, Provincia de Buenos Aires  1706
   Argentina

   Phone: +54 11 4650 8472
   Email: fernando@gont.com.ar
   URI:   http://www.gont.com.ar
























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