[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04

Network Working Group                                       M. Boucadair
Internet-Draft                                            France Telecom
Intended status: Informational                                  J. Touch
Expires: September 15, 2011                                      USC/ISI
                                                                P. Levis
                                                          France Telecom
                                                          March 14, 2011


   Analysis of Solution Candidates to Reveal the Origin IP Address in
                       Shared Address Deployments
             draft-boucadair-intarea-nat-reveal-analysis-01

Abstract

   This document analyzes a set of solution candidates which have been
   proposed to mitigate some of the issues encountered when address
   sharing is used.  In particular, this document focuses on means to
   reveal the origin of an IP packet when a Carrier Grade NAT is
   involved in the path.  The ultimate goal is to assess the viability
   of proposed solutions and hopefully to make a recommendation on the
   more suitable solution(s).

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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 September 15, 2011.

Copyright Notice




Boucadair, et al.      Expires September 15, 2011               [Page 1]


Internet-Draft       Revealing the origin IP address          March 2011


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


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Problem to Be Solved . . . . . . . . . . . . . . . . . . .  4
   2.  Recommendations  . . . . . . . . . . . . . . . . . . . . . . .  5
     2.1.  Preserve Source Port Number  . . . . . . . . . . . . . . .  7
   3.  Solutions Analysis . . . . . . . . . . . . . . . . . . . . . .  7
     3.1.  Define an IP Option  . . . . . . . . . . . . . . . . . . .  7
       3.1.1.  Description  . . . . . . . . . . . . . . . . . . . . .  7
       3.1.2.  Analysis . . . . . . . . . . . . . . . . . . . . . . .  8
     3.2.  Define a TCP Option  . . . . . . . . . . . . . . . . . . .  8
       3.2.1.  Description  . . . . . . . . . . . . . . . . . . . . .  8
       3.2.2.  Analysis . . . . . . . . . . . . . . . . . . . . . . .  8
     3.3.  Use the Identification Field of IP Header (IP-ID)  . . . .  9
       3.3.1.  Description  . . . . . . . . . . . . . . . . . . . . .  9
       3.3.2.  Analysis . . . . . . . . . . . . . . . . . . . . . . .  9
     3.4.  Inject Application Headers . . . . . . . . . . . . . . . . 10
       3.4.1.  Description  . . . . . . . . . . . . . . . . . . . . . 10
       3.4.2.  Analysis . . . . . . . . . . . . . . . . . . . . . . . 10
     3.5.  PROXY Protocol . . . . . . . . . . . . . . . . . . . . . . 11
       3.5.1.  Description  . . . . . . . . . . . . . . . . . . . . . 11
       3.5.2.  Analysis . . . . . . . . . . . . . . . . . . . . . . . 11
     3.6.  Enforce a Source-based Selection Algorithm at the
           Server Side  . . . . . . . . . . . . . . . . . . . . . . . 11
       3.6.1.  Description  . . . . . . . . . . . . . . . . . . . . . 11
       3.6.2.  Analysis . . . . . . . . . . . . . . . . . . . . . . . 12
     3.7.  Host Identity Protocol (HIP) . . . . . . . . . . . . . . . 12
       3.7.1.  Description  . . . . . . . . . . . . . . . . . . . . . 12
       3.7.2.  Analysis . . . . . . . . . . . . . . . . . . . . . . . 12
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   6.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 13
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 13



Boucadair, et al.      Expires September 15, 2011               [Page 2]


Internet-Draft       Revealing the origin IP address          March 2011


     7.2.  Informative References . . . . . . . . . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14

















































Boucadair, et al.      Expires September 15, 2011               [Page 3]


Internet-Draft       Revealing the origin IP address          March 2011


1.  Introduction

   As reported in [I-D.ietf-intarea-shared-addressing-issues], several
   issues are encountered when an IP address is shared among several
   subscribers.  Examples of such issues are listed below:

   o  Implicit authentication

   o  SPAM

   o  Blacklisting a mis-behaving user

   o  Redirect users with infected machines to a dedicated portal

   The sole use of the IPv4 address is not sufficient to uniquely
   distinguish a user.  As a mitigation, it is tempting to investigate
   means which would help in disclosing an information to be used by the
   remote server as a means to uniquely disambiguate packets of
   subscribers using the same IPv4 address.

   The purpose of this document is to analyze the solutions that have
   been proposed so far and to assess to what extent they solve the
   problem.

   Not need to remind that IPv6 is the only perennial solution.

   Only IPv4-based solutions are analyzed in the following sections:
   define a new IP option (Section 3.1), define a new TCP option
   (Section 3.2), use the Identification field of IP header (denoted as
   IP-ID, Section 3.3), inject application headers (Section 3.4), enable
   Proxy Protocol Section 3.5, use of port set (Section 3.6) and
   activate HIP (Section 3.7).

1.1.  Problem to Be Solved

   Observation: Today, servers use the source IPv4 address as an
   identifier to treat some incoming connections differently.  Tomorrow,
   due to the introduction of CGNs (e.g., NAT44, NAT64), that address
   will be shared.  In particular, when a server receives packets from
   the same source address.  Because this address is shared, the server
   does not know which host is the sending host.

   Objective: The server should be able to sort out the packets by
   sending host.

   Requirement: The server must have extra information than the source
   IP address to differentiate the sending host.  We call USER_HINT this
   information.



Boucadair, et al.      Expires September 15, 2011               [Page 4]


Internet-Draft       Revealing the origin IP address          March 2011


   For all solutions analyzed, we provide answers to the following
   questions:

   o  What is the USER_HINT?  It must be unique to each user under the
      same address.  It does not need to be globally unique.  Of course,
      the combination of the (public) IPv4 source address and the
      identifier ends up being relatively unique.  As unique as today's
      32-bit IPv4 addresses which, today, can change when a user re-
      connects.

   o  Where is the USER_HINT? (which protocol, which field): If the
      USER_HINT is put at the IP level, all packets will have to bear
      the identifier.  If it is put at a higher connection-oriented
      level, the identifier is only needed once in the session
      establishment phase (for instance TCP three-way-handshake), then,
      all packets received in this session will be attributed to the
      host id designated during the session opening.

   o  Who puts the USER_HINT?: For almost all the analyzed solutions,
      the address sharing function injects the USER_HINT.  When there
      are several address sharing functions in the data path, we
      describe to what extent the proposed solution is efficient.

   o  What are the security considerations?: Security consideration are
      common to all analyzed solutions (see Section 5).


2.  Recommendations

   The following Table 1 summarizes the approaches analyzed in this
   document.

   o  "Success ratio" indicates the ratio of successful communications
      when the option is used.  Provided figures are inspired from the
      results documented in [Options].

   o  "Deployable today" column indicates if the solution can be
      generalized without any constraint on current architectures and
      practices.












Boucadair, et al.      Expires September 15, 2011               [Page 5]


Internet-Draft       Revealing the origin IP address          March 2011


                   +---+---+----+---------+-------+----------+-----
                   |UDP|TCP|HTTP|Encrypted|Success|Deployable|Notes
                   |   |   |    | traffic | ratio | today?   |
        -----------+---+---+----+---------+-------+----------+-----
         IP option |Yes|Yes|Yes |    Yes  |   30% |  Yes     |
        -----------+---+---+----+---------+-------+----------+-----
        TCP option |No |Yes|Yes |    Yes  |   99% |  Yes     |
        -----------+---+---+----+---------+-------+----------+-----
             IP-ID |Yes|Yes|Yes |    Yes  |  100% |  Yes     | (1)
        -----------+---+---+----+---------+-------+----------+-----
        HTTP header|No |No |Yes |     No  |  100% |  Yes     | (2)
        -----------+---+---+----+---------+-------+----------+-----
        Proxy Proto| No|Yes|Yes |    Yes  |  Low  |  No      |
        -----------+---+---+----+---------+-------+----------+-----
          Port set |Yes|Yes|Yes |    Yes  |  100% |  Yes     |(1)(3)
        -----------+---+---+----+---------+-------+----------+-----
               HIP |-- |-- |--  |    --   |  Low  |   No     |(4)(5)
        -----------+---+---+----+---------+-------+----------+------

                  Table 1: Summary of analyzed solutions.

   Notes for the above table:

      (1) requires mechanism to advertise NAT is participating in this
      scheme (e.g., DNS PTR record)

      (2) this solution is widely deployed

      (3) when the port set is not advertised, the solution is less
      efficient.

      (4) requires the client and the server to be HIP-compliant and HIP
      infrastructure to be deployed.

      (5) if the client and the server are HIP-enabled, the address
      sharing function does not need to insert a user-hint.  If the
      client is not HIP-enabled, designing the device that performs
      address sharing to act as a UDP/TCP-HIP relay is not viable.



   According to the above table and the analysis elaborated in
   Section 3:

   o  IP Option, IP-ID and Proxy Protocol proposals are broken;

   o  HIP is not largely deployed;




Boucadair, et al.      Expires September 15, 2011               [Page 6]


Internet-Draft       Revealing the origin IP address          March 2011


   o  The use of Port Set may contradict the port randomization
      [RFC6056] requirement identified in
      [I-D.ietf-intarea-shared-addressing-issues];

   o  XFF is de facto standard deployed and supported in operational
      networks (e.g., HTTP Severs, Load-Balancers, etc.).

   o  From an application standpoint, the TCP Option is superior to XFF
      since it is not restricted to HTTP.  Nevertheless XFF is
      compatible with the presence of address sharing and load-balancers
      in the communication path.  To provide a similar functionality,
      the TCP Option may be extended to allow conveying a list of IP
      addresses to not loose the source IP address in the presence of
      load-balancers.

2.1.  Preserve Source Port Number

   In order to implement the recommendation documented in
   [I-D.ietf-intarea-server-logging-recommendations], extensions are
   required to preserve the source port number and to avoid this
   information to be lost when load-balancers are involved in the path.
   Examples of mitigation solutions are provided below:

   1.  Extend XFF to convey the port in addition to the IP address

   2.  Define a header similar to XFF to convey the source port

   3.  Extend the TCP Option to convey the source port

   4.  Enable the Proxy Protocol [Proxy].

   [[Note: Is there an interest to consider this issue or this should be
   left out of scope of this I-D?]].


3.  Solutions Analysis

3.1.  Define an IP Option

3.1.1.  Description

   This proposal aims to define an IP option [RFC0791] to convey a "user
   identifier".  This identifier can be inserted by the address sharing
   function to uniquely distinguish a user among those sharing the same
   IP address.  The option can convey an IPv4 address, the prefix part
   of an IPv6 address, etc.

   Another way for using IP option has been described in Section 4.6 of



Boucadair, et al.      Expires September 15, 2011               [Page 7]


Internet-Draft       Revealing the origin IP address          March 2011


   [RFC3022].

3.1.2.  Analysis

   Unlike the solution presented in Section 3.2, this proposal can apply
   for any transport protocol.  Nevertheless, it is widely known that
   routers (and other middle boxes) filter IP options.  IP packets with
   IP options can be dropped by some IP nodes.  Previous studies
   demonstrated that "IP Options are not an option" (Refer to
   [Not_An_Option], [Options]).

   As a conclusion, using an IP option to convey a user-hint is not
   viable.

3.2.  Define a TCP Option

3.2.1.  Description

   This proposal [I-D.wing-nat-reveal-option] defines a new TCP option
   called CX-ID.  This option encloses the client's identifier (e.g., an
   IPv4 address, a subscriber ID, or 64 bits of an IPv6 address).  The
   address sharing device inserts this TCP option to the TCP SYN packet
   or in the initial ACK.

3.2.2.  Analysis

   The risk related to handling a new TCP option is low as measured in
   [Options].  Using a new TCP option to convey the user-hint does not
   require any modification to the applications but it is applicable
   only for TCP-based applications.  Applications relying on other
   transport protocols are therefore left unsolved.

   Some downsides have been raised against defining a TCP option to
   reveal a user identity:

   o  Conveying an IP address in a TCP option may be seen as a violation
      of OSI layers but since IP addresses are already used for the
      checksum computation, this is not seen as a blocking point.

   o  TCP option space is limited, and might be consumed by the TCP
      client.

   o  TCP options are not reliably transmitted.  If the first segment is
      lost and the payload bytes it contained are retransmitted, the
      retransmitted segment is not required to contain the same options
      as the lost segment.  [I-D.wing-nat-reveal-option] discusses two
      approaches to sending the USER_HINT: sending the USER_HINT in the
      TCP SYN (which consumes more bytes in the TCP header of the TCP



Boucadair, et al.      Expires September 15, 2011               [Page 8]


Internet-Draft       Revealing the origin IP address          March 2011


      SYN) and sending the USER_HINT in a TCP ACK (which consumes only
      two bytes in the TCP SYN).  Content providers may find it more
      desirable to receive the USER_HINT in the TCP SYN, as that more
      closely preserves the user hint received in the source IP address
      as per current practices.  It is more complicated to implement
      sending the USER_HINT in a TCP ACK, as it can introduce MTU issues
      if the ACK packet also contains TCP data, or a TCP segment is
      lost.

   o  When there are several NATs in the path, the original USER_HINT
      may be lost.  In such case, the procedure may not be efficient.

   o  Interference with current usages such as X-Forwarded-For (see
      Section 3.4) should be elaborated to specify the behavior of
      servers when both options are used; in particular specify which
      information to use: the content of the TCP option or what is
      conveyed in the application headers.

3.3.  Use the Identification Field of IP Header (IP-ID)

3.3.1.  Description

   IP-ID (Identification field of IP header) can be used to insert an
   information which uniquely distinguishes a user among those sharing
   the same IPv4 address.  An address sharing function can re-write the
   IP-ID field to insert a value unique to the user (16 bits are
   sufficient to uniquely disambiguate users sharing the same IP
   address).  Note that this field is not altered by some NATs; hence
   some side effects such as counting hosts behind a NAT as reported in
   [Count].

   A variant of this approach relies upon the format of certain packets,
   such as TCP SYN, where the IP-ID can be modified to contain a 16 bit
   user-hint.  Address sharing devices performing this function would
   require to indicate they are performing this function out of band,
   possibly using a special DNS record.

3.3.2.  Analysis

   This usage is not compliant with what is recommended in
   [I-D.ietf-intarea-ipv4-id-update].

   [TBC].

      [[Touch.NOTE: One other problem - picking an ID value here
      *requires* coordination, i.e., that no other IP packet with this
      IP address uses that ID within 2MSL.  Unless fragmentation is
      disabled for all packets all the time, you can't use *any* ID



Boucadair, et al.      Expires September 15, 2011               [Page 9]


Internet-Draft       Revealing the origin IP address          March 2011


      value without that coordination.]]

      [[Wing.NOTE: Most OSes today are emitting TCP packets with DF=1
      (OSX, Windows XP and 7, Linux, etc.).  So, we can assume the TCP
      SYN is going to have DF=1, and only insert IP-ID if DF=1 and it's
      a TCP SYN.  Doing that, I don't see any disagreement with Joe's
      IP-ID document.]]

3.4.  Inject Application Headers

3.4.1.  Description

   Another option is to not require any change at the transport nor the
   IP levels but to convey at the application payload the required
   information which will be used to disambiguate users.  This format
   and the related semantics depend on its application (e.g., HTTP, SIP,
   SMTP, etc.).

   For HTTP, the X-Forwarded-For (XFF) header can be used to display the
   original IP address when an address sharing device is involved.
   Service Providers operating address sharing devices can enable the
   feature of injecting the XFF header which will enclose the original
   IPv4 address or the IPv6 prefix part.  The address sharing device has
   to strip all included XFF headers before injecting their own.
   Servers may rely on the contents of this field to enforce some
   policies such as blacklisting misbehaving users.  Note that XFF can
   also be logged by some servers (this is for instance supported by
   Apache).

3.4.2.  Analysis

   Not all applications impacted by the address sharing can support the
   ability to disclose the original IP address.  Only a subset of
   protocols (e.g., HTTP) can rely on this solution.

   For the HTTP case, to prevent users injecting invalid user-hints, an
   initiative has been launched to maintain a list of trusted ISPs using
   XFF: See for example the list available at: [Trusted_ISPs] of trusted
   ISPs as maintained by Wikipedia.  If an address sharing device is on
   the trusted XFF ISPs list, users editing Wikipedia located behind the
   address sharing device will appear to be editing from their
   "original" IP address and not from the NATed IP address.  If an
   offending activity is detected, individual users can be blacklisted
   instead of all users sharing the same IP address.

   XFF header injection is a common practice of load balancers.  When a
   load balancer is in the path, the original content of any included
   XFF header should not be stripped.  Otherwise the information about



Boucadair, et al.      Expires September 15, 2011              [Page 10]


Internet-Draft       Revealing the origin IP address          March 2011


   the "origin" IP address will be lost.

   When several address sharing devices are crossed, XFF header can
   convey the list of IP addresses.  The origin USER_HINT can be exposed
   to the target server.

   XFF also introduces some implementation complexity if the HTTP packet
   is at or close to the MTU size.

   It has been reported that some "poor" implementation may encounter
   some parsing issues when injecting XFF header.

   For encrypted HTTP traffic, injecting XFF header may be broken.

3.5.  PROXY Protocol

3.5.1.  Description

   The solution, referred to as Proxy Protocol [Proxy], does not require
   any application-specific knowledge.  The rationale behind this
   solution is to prepend each connection with a line reporting the
   characteristics of the other side's connection as shown in the
   example below (excerpt from [Proxy]):

       PROXY TCP4 192.168.0.1 192.168.0.11 56324 443\r\n

   Upon receipt of a message conveying this line, the server removes the
   line.  The line is parsed to retrieve the transported protocol.  The
   content of this line is recorded in logs and used to enforce
   policies.

3.5.2.  Analysis

   This solution can be deployed in a controlled environment but it can
   not be deployed to all access services available in the Internet.  If
   the remote server does not support the Proxy Protocol, the session
   will fail.  Other complications will raise due to the presence of
   firewalls for instance.

   As a consequence, this solution is broken and can not be recommended.

3.6.  Enforce a Source-based Selection Algorithm at the Server Side

3.6.1.  Description

   This solution proposal does not require any action from the address
   sharing function to disclose an user identifier.  Instead of assuming
   all the ports are associated with the same user, a random-based



Boucadair, et al.      Expires September 15, 2011              [Page 11]


Internet-Draft       Revealing the origin IP address          March 2011


   algorithm (or any port selection method) is run to generate the set
   of ports (including the source port of the received packet).  The
   length of the ports set to be generated by the server may be
   configurable (e.g., 8, 32, 64, 512, 1024, etc.).  Instead of a
   random-based scheme, the server can use contiguous port ranges to
   form the port sets.

   The server may reduce (or enlarge) the width of the ports set of the
   misbehaving action is (not) mitigated.

   A variant of this proposal is to announce by off-line means the port
   set assignment policy of an operator.

3.6.2.  Analysis

   In nominal mode, no coordination is required between the address
   sharing function and the server side but the efficiency of the method
   depends on the port set selection algorithm.

   The method is more efficient if the provider that operates the
   address sharing device advertises its port assignment policy but this
   may contradicts the port randomization as identified in
   [I-D.ietf-intarea-shared-addressing-issues].

   The server is free to implement the actions (e.g., blacklist all the
   ports) it judges required to mitigate an abuse attack.

3.7.  Host Identity Protocol (HIP)

3.7.1.  Description

   [RFC5201] specifies an architecture which introduces a new namespace
   to convey an identity information.

3.7.2.  Analysis

   This solution requires both the client and the server to support HIP
   [RFC5201].  Additional architectural considerations are to be taken
   into account such as the key exchanges, etc.

   If the address sharing function is required to act as a UDP/TCP-HIP
   relay, this is not a viable option.


4.  IANA Considerations

   This document does not require any action from IANA.




Boucadair, et al.      Expires September 15, 2011              [Page 12]


Internet-Draft       Revealing the origin IP address          March 2011


5.  Security Considerations

   The same security concerns apply for the injection of an IP option,
   TCP option and application-related content (e.g., XFF) by the address
   sharing device.  If the server trusts the content of the user-hint
   field, a third party user can be impacted by a misbehaving user to
   reveal a "faked" original IP address.


6.  Acknowledgments

   Many thanks to D. Wing and C. Jacquenet for their review, comments
   and inputs.

   Some of the issues related to defining a new TCP option have been
   raised by L. Eggert.


7.  References

7.1.  Normative References

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              September 1981.

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

   [RFC3022]  Srisuresh, P. and K. Egevang, "Traditional IP Network
              Address Translator (Traditional NAT)", RFC 3022,
              January 2001.

   [RFC6056]  Larsen, M. and F. Gont, "Recommendations for Transport-
              Protocol Port Randomization", BCP 156, RFC 6056,
              January 2011.

7.2.  Informative References

   [Count]    "A technique for counting NATted hosts",
              <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>.

   [I-D.ietf-intarea-ipv4-id-update]
              Touch, J., "Updated Specification of the IPv4 ID Field",
              draft-ietf-intarea-ipv4-id-update-01 (work in progress),
              October 2010.

   [I-D.ietf-intarea-server-logging-recommendations]
              Durand, A., Gashinsky, I., Lee, D., and S. Sheppard,



Boucadair, et al.      Expires September 15, 2011              [Page 13]


Internet-Draft       Revealing the origin IP address          March 2011


              "Logging recommendations for Internet facing servers",
              draft-ietf-intarea-server-logging-recommendations-03 (work
              in progress), February 2011.

   [I-D.ietf-intarea-shared-addressing-issues]
              Ford, M., Boucadair, M., Durand, A., Levis, P., and P.
              Roberts, "Issues with IP Address Sharing",
              draft-ietf-intarea-shared-addressing-issues-05 (work in
              progress), March 2011.

   [I-D.wing-nat-reveal-option]
              Yourtchenko, A. and D. Wing, "Revealing hosts sharing an
              IP address using TCP option",
              draft-wing-nat-reveal-option-01 (work in progress),
              February 2011.

   [Not_An_Option]
              R. Fonseca, G. Porter, R. Katz, S. Shenker, and I.
              Stoica,, "IP options are not an option", 2005, <http://
              www.eecs.berkeley.edu/Pubs/TechRpts/2005/
              EECS-2005-24.html>.

   [Options]  Alberto Medina, Mark Allman, Sally Floyd, "Measuring
              Interactions Between Transport Protocols and Middleboxes",
              2005, <http://conferences.sigcomm.org/imc/2004/papers/
              p336-medina.pdf>.

   [Proxy]    Tarreau, W., "The PROXY protocol", November 2010, <http://
              haproxy.1wt.eu/download/1.5/doc/proxy-protocol.txt>.

   [RFC5201]  Moskowitz, R., Nikander, P., Jokela, P., and T. Henderson,
              "Host Identity Protocol", RFC 5201, April 2008.

   [Trusted_ISPs]
              "Trusted XFF list", <http://meta.wikimedia.org/wiki/
              XFF_project#Trusted_XFF_list>.


Authors' Addresses

   Mohamed Boucadair
   France Telecom
   Rennes,   35000
   France

   Email: mohamed.boucadair@orange-ftgroup.com





Boucadair, et al.      Expires September 15, 2011              [Page 14]


Internet-Draft       Revealing the origin IP address          March 2011


   Joe Touch
   USC/ISI


   Email: touch@isi.edu


   Pierre Levis
   France Telecom
   Caen,   14000
   France

   Email: pierre.levis@orange-ftgroup.com






































Boucadair, et al.      Expires September 15, 2011              [Page 15]


Html markup produced by rfcmarkup 1.129d, available from https://tools.ietf.org/tools/rfcmarkup/