NETCONF over TLS update: Updates to Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication

Internet Engineering Task Force (IETF)                         S. Turner
Request for Comments: 9918                                         sn3rd
Updates: 7589                                                 R. Housley
Category: Standards Track                                 Vigil Security
ISSN: 2070-1721                                                July 2026


  Updates to Using the NETCONF Protocol over Transport Layer Security
                 (TLS) with Mutual X.509 Authentication

Abstract

   RFC 7589 defines how to protect Network Configuration Protocol
   (NETCONF) messages with TLS 1.2.  This document updates RFC 7589 to
   update support requirements for TLS 1.2 and add TLS 1.3 support
   requirements, including restrictions on the use of TLS 1.3's early
   data.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc9918.

Copyright Notice

   Copyright (c) 2026 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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   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
   2.  Conventions
   3.  Early Data
   4.  Cipher Suites
   5.  Security Considerations
   6.  IANA Considerations
   7.  Normative References
   Acknowledgments
   Authors' Addresses

1.  Introduction

   [RFC7589] defines how to protect NETCONF messages [RFC6241] with TLS
   1.2 [RFC5246].  This document updates [RFC7589] to update support
   requirements for TLS 1.2 [RFC5246] and add TLS 1.3 [RFC9846] support
   requirements, including restrictions on the use of TLS 1.3's early
   data, which is also known as 0-RTT data.  It also updates
   "netconf-tls", the IANA-registered port number entry, to refer to
   this document.  All other provisions set forth in [RFC7589] are
   unchanged, including connection initiation, message framing,
   connection closure, certificate validation, server identity, and
   client identity.

      |  NOTE: Implementations that support TLS 1.3 [RFC9846] SHOULD
      |  also follow Sections 4 and 5 of [RFC7589].

2.  Conventions

   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
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Early Data

   Early data (aka 0-RTT data) is a mechanism defined in TLS 1.3
   [RFC9846] that allows a client to send data ("early data") as part of
   the first flight of messages to a server.  Note that TLS 1.3 can be
   used without early data as per Appendix F.5 of [RFC9846].  In fact,
   early data is permitted by TLS 1.3 only when the client and server
   share a Pre-Shared Key (PSK), either obtained externally or via a
   previous handshake.  The client uses the PSK to authenticate the
   server and to encrypt the early data.

   As noted in Section 2.3 of [RFC9846], the security properties for
   early data are weaker than those for subsequent TLS-protected data.
   In particular, early data is not forward secret, and there is no
   protection against the replay of early data between connections.
   Appendix F.5 of [RFC9846] requires applications not use early data
   without a profile that defines its use.  This document specifies that
   NETCONF implementations that support TLS 1.3 or later MUST NOT use
   early data.

4.  Cipher Suites

   Implementations MUST support mutually authenticated TLS 1.2
   [RFC5246], and they are, as specified in [RFC9325], recommended to
   support the cipher suites found in Section 4.2 of [RFC9325].

   Implementations MAY implement additional TLS 1.2 cipher suites that
   provide mutual authentication [RFC5246] and confidentiality, as
   required by NETCONF [RFC6241].

   Implementations SHOULD support mutually authenticated TLS 1.3
   [RFC9846] and, if implemented, MUST prefer to negotiate TLS 1.3 over
   earlier versions of TLS.

   Implementations that support TLS 1.3 [RFC9846] are REQUIRED to
   support the mandatory-to-implement cipher suites listed in
   Section 9.1 of [RFC9846].

   Implementations that support TLS 1.3 MAY implement additional TLS
   cipher suites that provide mutual authentication and confidentiality,
   which are required for NETCONF [RFC6241].

5.  Security Considerations

   The security considerations of [RFC6241], [RFC7589], and [RFC9325]
   apply here as well.

   NETCONF implementations SHOULD follow the TLS recommendations given
   in [RFC9325].

   For implementations that support TLS 1.3, the security considerations
   of TLS 1.3 [RFC9846] apply.

   As specified in [RFC7589], NETCONF over TLS requires mutual
   authentication.

   For implementations that support TLS 1.3 [RFC9846]:

      TLS 1.3 mutual authentication is used to ensure that only
      authorized users and systems are able to view the NETCONF server's
      configuration and state or to modify the NETCONF server's
      configuration.  To this end, neither the client nor the server
      should establish a NETCONF over TLS 1.3 connection with an
      unknown, unexpected, or incorrectly identified peer; see Section 7
      of [RFC7589].  If deployments make use of a trusted list of
      Certification Authority (CA) certificates [RFC5280], then the
      listed CAs should only issue certificates to parties that are
      authorized to access the NETCONF servers.  Doing otherwise will
      allow certificates that were issued for other purposes to be
      inappropriately accepted by a NETCONF server.

   The security considerations of [RFC9525] apply to all implementations
   when the client checks the identity of the server, as is required in
   Section 6 of [RFC7589].

6.  IANA Considerations

   IANA has added a reference to this document in the "netconf-tls"
   entry in the "Service Name and Transport Protocol Port Number
   Registry".  The updated registry entry appears as follows:

   Service Name:  netconf-tls
   Port Number:  6513
   Transport Protocol:  tcp
   Description:  NETCONF over TLS
   Assignee:  IESG <iesg@ietf.org>
   Contact:  IETF Chair <chair@ietf.org>
   Reference:  RFC 7589, RFC 9918

7.  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>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <https://www.rfc-editor.org/info/rfc5280>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC7589]  Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
              NETCONF Protocol over Transport Layer Security (TLS) with
              Mutual X.509 Authentication", RFC 7589,
              DOI 10.17487/RFC7589, June 2015,
              <https://www.rfc-editor.org/info/rfc7589>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC9325]  Sheffer, Y., Saint-Andre, P., and T. Fossati,
              "Recommendations for Secure Use of Transport Layer
              Security (TLS) and Datagram Transport Layer Security
              (DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
              2022, <https://www.rfc-editor.org/info/rfc9325>.

   [RFC9525]  Saint-Andre, P. and R. Salz, "Service Identity in TLS",
              RFC 9525, DOI 10.17487/RFC9525, November 2023,
              <https://www.rfc-editor.org/info/rfc9525>.

   [RFC9846]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 9846, DOI 10.17487/RFC9846, July 2026,
              <https://www.rfc-editor.org/info/rfc9846>.

Acknowledgments

   We would like to thank Per Andersson, Jürgen Schönwälder, Jeff
   Hartley, Rob Wilton, and Qin Wu for their reviews.

Authors' Addresses

   Sean Turner
   sn3rd
   Email: sean@sn3rd.com


   Russ Housley
   Vigil Security, LLC
   516 Dranesville Road
   Herndon, VA 20170
   United States of America
   Email: housley@vigilsec.com