TLS Client Network Address Extension
draft-kinnear-tls-client-net-address-00

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Last updated 2019-03-11
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Network Working Group                                         E. Kinnear
Internet-Draft                                                  T. Pauly
Intended status: Informational                                   C. Wood
Expires: September 12, 2019                                   Apple Inc.
                                                          March 11, 2019

                  TLS Client Network Address Extension
                draft-kinnear-tls-client-net-address-00

Abstract

   This document describes a TLS 1.3 extension that can be by clients to
   request their public network address from a server.  This information
   can be used for a variety of purposes, including: NAT detection, ASN
   identification, and privacy-driven transport protocol features.

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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 12, 2019.

Copyright Notice

   Copyright (c) 2019 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.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  Client Network Address Use Cases  . . . . . . . . . . . . . .   2
     2.1.  Connection Lifetime Optimizations . . . . . . . . . . . .   3
     2.2.  Privacy Stance Enhancements . . . . . . . . . . . . . . .   3
     2.3.  Metric Collections  . . . . . . . . . . . . . . . . . . .   3
   3.  Network Address Extension . . . . . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   This document describes a TLS 1.3 [RFC8446] extension that can be by
   clients to request their public network address from a server.  This
   has several uses, including: NAT detection, ASN identification, and
   privacy-driven transport protocol features.  Servers that support
   this extension can send the perceived client address to clients.  The
   latter may then confirm whether or not this representation matches
   their known public address.

   Unlike the related NAT detection extension for IKE [RFC3947], clients
   do not send their perceived IP address to servers, even in an
   obfuscated form.  Doing so would introduce an unwanted privacy
   regression for clients.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119] [RFC8174] when, and only when, they appear in all capitals,
   as shown here.

2.  Client Network Address Use Cases

   Knowledge of a public client network address can serve several
   purposes.  This extension allows clients to detect the presence of a
   NAT or other address-transforming proxy involved in a TLS connection.
   The following sections descibe several uses for this information.

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2.1.  Connection Lifetime Optimizations

   Middleboxes such as NATs typically have short lifetimes for
   connection state.  Detecting such middleboxes may help influence
   client connection management logic, such as the use of keep-alive
   messages.

   Since NATs often apply to all traffic from an endhost, detection via
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