NETCONF over TLS update: Updates to Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication
Updated TLS rules for NETCONF: TLS 1.2 stays mandatory, TLS 1.3 is added, and early data is banned.
Turner, S. and R. Housley, "Updates to Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication", RFC 9918, DOI 10.17487/RFC9918, July 2026, <https://www.rfc-editor.org/info/rfc9918>.
@misc{rfc9918,
series = {Request for Comments},
number = 9918,
howpublished = {RFC 9918},
publisher = {RFC Editor},
doi = {10.17487/RFC9918},
url = {https://www.rfc-editor.org/info/rfc9918},
author = {S. Turner and R. Housley},
title = {{Updates to Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication}},
pagetotal = 5,
year = 2026,
month = jul,
} RFC text
Contents
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
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 Revised BSD License text as described in Section 4.e of the
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
AI ELI5
On this page
§1What This Update Changes
RFC 7589 defines how to protect NETCONF messages with TLS 1.2. This document updates it in three ways: it updates the support requirements for TLS 1.2, it adds TLS 1.3 support requirements including limits on early data, and it updates the IANA-registered netconf-tls port entry to refer to this document.
All other provisions of RFC 7589 are unchanged, including connection initiation, message framing, connection closure, certificate validation, server identity and client identity. Implementations that support TLS 1.3 SHOULD also follow Sections 4 and 5 of RFC 7589.
There was already a rulebook for locking network management messages in a safe. This note adds rules for the newer kind of lock and leaves the rest alone.
§3Early Data Is Not Allowed
Early data, also called 0-RTT data, is a TLS 1.3 mechanism that lets a client send data in the first flight of messages to a server. It is permitted only when client and server share a Pre-Shared Key (PSK). TLS 1.3 can be used without it.
The security properties of early data are weaker than those of later TLS-protected data. It is not forward secret, and there is no protection against replay of early data between connections. This document therefore specifies that NETCONF implementations that support TLS 1.3 or later MUST NOT use early data.
Sending your message before the secret handshake is finished is risky, because someone could copy it and send it again. NETCONF is not allowed to do that.
§4TLS Versions and Cipher Suites
Implementations MUST support mutually authenticated TLS 1.2 and are recommended to support the cipher suites in Section 4.2 of RFC 9325. They MAY implement additional TLS 1.2 cipher suites that provide mutual authentication and confidentiality.
Implementations SHOULD support mutually authenticated TLS 1.3 and, if they implement it, MUST prefer to negotiate TLS 1.3 over earlier versions. Those that support TLS 1.3 are REQUIRED to support the mandatory-to-implement cipher suites in Section 9.1 of RFC 9846, and MAY implement additional suites that provide mutual authentication and confidentiality.
NETCONF over TLS still requires mutual authentication, so neither side should connect to an unknown, unexpected or incorrectly identified peer. Where a trusted list of CA certificates is used, the listed CAs should only issue certificates to parties authorized to access the NETCONF servers.
The older lock must always work, the newer lock is strongly encouraged, and if both sides have the newer lock they should use it. Both sides must also show ID to each other.
§6The netconf-tls Registry Entry
IANA added a reference to this document in the netconf-tls entry of the Service Name and Transport Protocol Port Number Registry. The entry is for port 6513 over tcp, described as NETCONF over TLS, and its reference now reads RFC 7589, RFC 9918.
The phone book entry for this service now lists this note too, but the phone number did not change.