SOCKS Protocol Version 6
draft-olteanu-intarea-socks-6-08

Document Type Active Internet-Draft (individual)
Last updated 2019-11-04
Replaces draft-olteanu-socks-6, draft-intarea-olteanu-socks-6
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Internet Area Working Group                                   V. Olteanu
Internet-Draft                                              D. Niculescu
Intended status: Experimental        University Politehnica of Bucharest
Expires: May 7, 2020                                   November 04, 2019

                        SOCKS Protocol Version 6
                    draft-olteanu-intarea-socks-6-08

Abstract

   The SOCKS protocol is used primarily to proxy TCP connections to
   arbitrary destinations via the use of a proxy server.  Under the
   latest version of the protocol (version 5), it takes 2 RTTs (or 3, if
   authentication is used) before data can flow between the client and
   the server.

   This memo proposes SOCKS version 6, which reduces the number of RTTs
   used, takes full advantage of TCP Fast Open, and adds support for
   0-RTT authentication.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on May 7, 2020.

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
   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

Olteanu & Niculescu        Expires May 7, 2020                  [Page 1]
Internet-Draft                   SOCKS 6                   November 2019

   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Revision log  . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Requirements language . . . . . . . . . . . . . . . . . . . .  10
   3.  Mode of operation . . . . . . . . . . . . . . . . . . . . . .  10
   4.  Requests  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   5.  Version Mismatch Replies  . . . . . . . . . . . . . . . . . .  13
   6.  Authentication Replies  . . . . . . . . . . . . . . . . . . .  13
   7.  Operation Replies . . . . . . . . . . . . . . . . . . . . . .  14
     7.1.  Handling CONNECT  . . . . . . . . . . . . . . . . . . . .  16
     7.2.  Handling BIND . . . . . . . . . . . . . . . . . . . . . .  16
     7.3.  Handling UDP ASSOCIATE  . . . . . . . . . . . . . . . . .  16
       7.3.1.  Proxying UDP servers  . . . . . . . . . . . . . . . .  19
       7.3.2.  Proxying multicast traffic  . . . . . . . . . . . . .  19
   8.  SOCKS Options . . . . . . . . . . . . . . . . . . . . . . . .  19
     8.1.  Stack options . . . . . . . . . . . . . . . . . . . . . .  20
       8.1.1.  IP TOS options  . . . . . . . . . . . . . . . . . . .  21
       8.1.2.  Happy Eyeballs options  . . . . . . . . . . . . . . .  21
       8.1.3.  TFO options . . . . . . . . . . . . . . . . . . . . .  22
       8.1.4.  Multipath options . . . . . . . . . . . . . . . . . .  22
       8.1.5.  Listen Backlog options  . . . . . . . . . . . . . . .  23
     8.2.  Authentication Method options . . . . . . . . . . . . . .  24
     8.3.  Authentication Data options . . . . . . . . . . . . . . .  25
     8.4.  Session options . . . . . . . . . . . . . . . . . . . . .  26
       8.4.1.  Session initiation  . . . . . . . . . . . . . . . . .  26
       8.4.2.  Further SOCKS Requests  . . . . . . . . . . . . . . .  27
       8.4.3.  Tearing down the session  . . . . . . . . . . . . . .  28
     8.5.  Idempotence options . . . . . . . . . . . . . . . . . . .  29
       8.5.1.  Requesting a token window . . . . . . . . . . . . . .  29
       8.5.2.  Spending a token  . . . . . . . . . . . . . . . . . .  30
       8.5.3.  Shifting windows  . . . . . . . . . . . . . . . . . .  32
       8.5.4.  Out-of-order Window Advertisements  . . . . . . . . .  32
   9.  Username/Password Authentication  . . . . . . . . . . . . . .  32
   10. TCP Fast Open on the Client-Proxy Leg . . . . . . . . . . . .  33
   11. False Starts  . . . . . . . . . . . . . . . . . . . . . . . .  33
   12. DNS provided by SOCKS . . . . . . . . . . . . . . . . . . . .  34
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