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RTCWEB                                                         J. Uberti
Internet-Draft                                               J. de Borst
Intended status: Informational                                   Q. Wang
Expires: May 7, 2019                                              Google
                                                               Y. Fablet
                                                              Apple Inc.
                                                       November 03, 2018


        WebRTC IP Address Handling Extensions for Multicast DNS
               draft-uberti-rtcweb-ip-handling-ex-mdns-00

Abstract

   This document extends the previous WebRTC IP Address Handling
   Requirements with new modes that make use of Multicast DNS ICE
   candidates, and updates the recommendations accordingly.

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/.

   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 May 7, 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
   Provisions Relating to IETF Documents
   (https://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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  New Modes . . . . . . . . . . . . . . . . . . . . . . . . . .   2
     3.1.  Mode 2.1  . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Mode 2.2  . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Analysis  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Additional Applications . . . . . . . . . . . . . . . . . . .   3
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   [IPHandling] describes the privacy problems associated with exposing
   IP addresses to web applications, but admits that there is no
   solution to the issue of exposing private IP addresses that does not
   carry a corresponding impact on connectivity.

   [mDNSCandidates] introduces a new technique based on Multicast DNS
   (mDNS) that obscures private IP addresses with mDNS names.  This
   solves the privacy issues associated with exposing local IP
   addresses, and mitigates most of the aforementioned connectivity
   impact.

   This document extends the set of modes defined in [IPHandling] with
   new options based on the mDNS technique.  Different choices are
   provided, each with their own benefits and drawbacks.

2.  Terminology

   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].

3.  New Modes

   Using the mDNS technique, we define two new modes, namely Mode 2.1
   and 2.2.  These modes are identical to Mode 2 from [IPHandling], but
   the technique from [mDNSCandidates] is used to protect the selected
   private IP addresses.  Accordingly, the privacy guidelines outlined



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   in [mDNSCandidates], Section 5 MUST be followed in each new mode in
   order to prevent accidental disclosure of a private IP address.

3.1.  Mode 2.1

   The local IPv4 address associated with the preferred interface MUST
   be replaced with a mDNS name, as described in [mDNSCandidates],
   Section 3.1.  Any local IPv6 addresses associated with the preferred
   interface MUST also be replaced with mDNS names, unless they are
   [RFC4941] privacy-preserving addresses.

3.2.  Mode 2.2

   All local IPv4 and IPv6 addresses MUST be replaced with mDNS names,
   as described in [mDNSCandidates], Section 3.1.

4.  Analysis

   The only difference between Mode 2.1 and Mode 2.2 is how [RFC4941]
   addresses are handled.  In either case, a direct connection is
   possible if the mDNS addresses created for the local IP addresses can
   be resolved.  However, when mDNS fails, either because it is disabled
   on the network, or the endpoints are not on the same segment, Mode
   2.1 may allow a direct connection where Mode 2.2 does not.

   The exact impact on applications needs to be determined
   experimentally.  This document will be updated with a specific
   recommendation once this information is known.

5.  Additional Applications

   The mDNS technique may also have value even when all network
   interfaces are used by the ICE agent, i.e., in Mode 1 from
   [IPHandling], by minimizing the amount of information regarding the
   local network that is disclosed to the remote peer.  Accordingly, a
   future update of this document may define additional modes that apply
   the mDNS technique to Mode 1.  This is an area for further study.

6.  Security Considerations

   The modes defined here, on their own, present no new security
   considerations.  Considerations for the mDNS technique are detailed
   in [mDNSCandidates], Section 6.








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7.  IANA Considerations

   This document requires no actions from IANA.

8.  References

8.1.  Normative References

   [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>.

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
              <https://www.rfc-editor.org/info/rfc4941>.

8.2.  Informative References

   [IPHandling]
              Shieh, G., "WebRTC IP Address Handling Requirements",
              April 2018, <https://tools.ietf.org/html/
              draft-ietf-rtcweb-ip-handling>.

   [mDNSCandidates]
              Wang, Q., "Using Multicast DNS to protect privacy when
              exposing ICE candidates", October 2018,
              <https://tools.ietf.org/html/
              draft-ietf-rtcweb-mdns-ice-candidates>.

Authors' Addresses

   Justin Uberti
   Google

   Email: juberti@google.com


   Jeroen de Borst
   Google

   Email: jeroendb@google.com








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   Qingsi Wang
   Google

   Email: qingsi@google.com


   Youenn Fablet
   Apple Inc.

   Email: youenn@apple.com









































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