The OpenConnect VPN Protocol Version 1.1
draft-mavrogiannopoulos-openconnect-02

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Network Working Group                               N. Mavrogiannopoulos
Internet-Draft                                                   Red Hat
Intended status: Informational                          October 14, 2018
Expires: April 17, 2019

                The OpenConnect VPN Protocol Version 1.1
                 draft-mavrogiannopoulos-openconnect-02

Abstract

   This document specifies version 1.1 of the OpenConnect Virtual
   Private Network (VPN) protocol, a secure VPN protocol that provides
   communications privacy over the Internet.  That protocol is believed
   to be compatible with CISCO's AnyConnect VPN protocol.  The protocol
   allows the establishment of VPN tunnels in a way that is designed to
   prevent eavesdropping, tampering, or message forgery.

Status of This Memo

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   This Internet-Draft will expire on April 17, 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
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   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of

Mavrogiannopoulos        Expires April 17, 2019                 [Page 1]
Internet-Draft         The OpenConnect Version 1.1          October 2018

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Terminology  . . . . . . . . . . . . . . . .   3
     1.2.  Goals of This Document  . . . . . . . . . . . . . . . . .   3
   2.  The OpenConnect Protocol  . . . . . . . . . . . . . . . . . .   3
     2.1.  VPN Session Establishment . . . . . . . . . . . . . . . .   3
       2.1.1.  Server Authentication . . . . . . . . . . . . . . . .   3
       2.1.2.  Client Authentication . . . . . . . . . . . . . . . .   4
       2.1.3.  Exchange of Session Parameters  . . . . . . . . . . .   9
       2.1.4.  Establishment of Primary TCP Channel (CSTP) . . . . .  10
       2.1.5.  Establishment of Secondary UDP Channel (DTLS) . . . .  11
     2.2.  The CSTP Channel Protocol . . . . . . . . . . . . . . . .  14
     2.3.  The DTLS Channel Protocol . . . . . . . . . . . . . . . .  15
     2.4.  The Channel Re-Key Protocol . . . . . . . . . . . . . . .  15
     2.5.  The Keepalive and Dead Peer Detection Protocols . . . . .  16
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  18
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .  18
   Appendix A.  Name for Application-Layer Protocol Negotiation  . .  21
   Appendix B.  Compression  . . . . . . . . . . . . . . . . . . . .  21
   Appendix C.  DTD declarations . . . . . . . . . . . . . . . . . .  21
     C.1.  config-auth.dtd . . . . . . . . . . . . . . . . . . . . .  21
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  22

1.  Introduction

   The purpose of this document is to specify the OpenConnect VPN
   protocol in a detail in order to allow for multiple interoperable
   implementations.  This is the protocol used by the OpenConnect client
   and server [OPENCONNECT-CLIENT][OPENCONNECT-SERVER], and is believed
   to be compatible with CISCO's AnyConnect protocol.

   This protocol's design follows a minimalistic modular philosophy.  It
   delegates several protocol-related elements often considered as core
   VPN features and diversifiers, to standards protocols.  That
   delegation, allows a minimalistic core protocol which contains very
   few security related elements and is decoupled from cryptography.
   That in turn transfers the auditing requirements due to cryptographic
   and negotiation protocols to dedicated for that purpose components.
   In particular the Openconnect VPN protocol uses standard protocols
   such as HTTP, TLS [RFC8446] and DTLS [RFC6347] to provide a VPN with
   data security and authenticity.
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