Operations and Management Area Working Group
Internet Engineering Task Force (IETF) M. Boucadair, Ed.
Internet-Draft
Request for Comments: 9950 Orange
Obsoletes: 9105 (if approved) B. Wu
Intended status:
Category: Standards Track Huawei Technologies
Expires: 8 January
ISSN: 2070-1721 March 2026 7 July 2025
A YANG Data Model for Terminal Access Controller Access-Control System
Plus (TACACS+)
draft-ietf-opsawg-secure-tacacs-yang-13
Abstract
This document defines a Terminal Access Controller Access-Control
System Plus (TACACS+) client YANG module that augments the System
Management data model, defined in RFC 7317, to allow devices to make
use of TACACS+ servers for centralized Authentication, Authorization,
and Accounting (AAA). Specifically, this document defines a YANG
module for TACACS+ over TLS 1.3.
This document obsoletes RFC 9105.
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 an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of six months RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 8 January 2026.
https://www.rfc-editor.org/info/rfc9950.
Copyright Notice
Copyright (c) 2025 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)
(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
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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
1.1. Changes Since RFC 9105 . . . . . . . . . . . . . . . . . 3
1.2. Editorial Note (To be removed by RFC Editor) . . . . . . 3
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 4
2.1. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4
3. Design of the TACACS+ Data Model . . . . . . . . . . . . . . 4
4. TACACS+ Client Module . . . . . . . . . . . . . . . . . . . . 8
5. Operational Considerations . . . . . . . . . . . . . . . . . 26
6. Security Considerations . . . . . . . . . . . . . . . . . . . 26
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1. Normative References . . . . . . . . . . . . . . . . . . 27
8.2. Informative References . . . . . . . . . . . . . . . . . 30
Appendix A. Example TACACS+ Authentication Configuration with
Shared Secret . . . . . . . . . . . . . . . . . . . . . . 31
Appendix B. TACACS+TLS Examples . . . . . . . . . . . . . . . . 32
B.1. Example TACACS+ Authentication Configuration with Explicit
Certificate Definitions . . . . . . . . . . . . . . . . . 32
B.2. Example TACACS+ Authentication Configuration with
Certificate References . . . . . . . . . . . . . . . . . 34
Appendix C. Full Tree . . . . . . . . . . . . . . . . . . . . . 36
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 46
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 47
1. Introduction
The System Management data model [RFC7317] defines separate
functionality to support local and Remote Authentication Dial In Dial-In User
Service (RADIUS) authentication:
User Authentication Model: Defines a list of user names with
associated passwords and a configuration leaf to decide the order
in which local or RADIUS authentication is used.
RADIUS Client Model: Defines a list of RADIUS servers used by a
device for centralized user authentication.
[RFC9105] defines a YANG module ("ietf-system-tacacs-plus") that
augments the System Management data model [RFC7317] for the
management of Terminal Access Controller Access-Control System Plus
(TACACS+) clients as an alternative to RADIUS servers [RFC2865].
Typically, the "ietf-system-tacacs-plus" module is used to configure
a TACACS+ client on a device to support deployment scenarios with
centralized authentication, authorization, Authentication, Authorization, and accounting Accounting (AAA)
servers.
This document defines a YANG module for managing TACACS+ clients
(Section 4), including TACACS+ over TLS 1.3 clients
[I-D.ietf-opsawg-tacacs-tls13]. [RFC9887]. This
document obsoletes [RFC9105].
The YANG module in this document conforms to the Network Management
Datastore Architecture (NMDA) defined in [RFC8342].
1.1. Changes Since RFC 9105
The following changes have been made to [RFC9105]:
* Add Added support for TLS [I-D.ietf-opsawg-tacacs-tls13] [RFC9887]
* Add Added a constraint to ensure that the list of servers is unique
per address/port number
* Update Updated the description of 'address' to be consistent with the
type
* Fix Fixed a must 'must' statement under 'tacacs-plus'
* Fix Fixed errors in the example provided in Appendix A of [RFC9105]
* Add Added an example to illustrate the use of VRF VPN Routing and
Forwarding (VRF)
* Add Added new examples to illustrate the use of TACACS+TLS data nodes
Detailed YANG changes to the YANG module are listed in Section 4.
2. Conventions and Definitions
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.
The terminology for describing YANG data models is defined in
[RFC7950].
The document uses the terms defined in Section 2 of
[I-D.ietf-opsawg-tacacs-tls13] [RFC9887] and
Section 3 of [RFC8907].
'client' refers to a TACACS+ client, while 'server' refers to a
TACACS+ server.
2.1. Tree Diagrams
The tree diagram diagrams used in this document follows follow the notation defined
in [RFC8340].
3. Design of the TACACS+ Data Model
This module is used to configure a TACACS+ client on a device to
support deployment scenarios with centralized authentication,
authorization, Authentication,
Authorization, and accounting Accounting (AAA) servers. Authentication is used
to validate a user's username and password, authorization allows the
user to access and execute commands at various privilege levels
assigned to the user, and accounting keeps track of the activity of a
user who has accessed the device.
The "ietf-system-tacacs-plus" module augments the '/sys:system' path
defined in the "ietf-system" module with the contents of the 'tacacs-
plus' grouping. Therefore, a device can use local, RADIUS, or
TACACS+ authentication to validate users who attempt to access the
device by several mechanisms, e.g., a command line interface or a
web-based user interface.
The 'server' list, which is directly under the 'tacacs-plus'
container, holds a list of TACACS+ servers and uses 'server-type' to
distinguish between Authentication, Authorization, and Accounting
(AAA) AAA services. The list of servers is for
redundancy.
When there are multiple interfaces connected to a TACACS+ client or
server, the source address of outgoing TACACS+ packets could be
specified, or the source address could be specified through the
interface IP address setting or derived from the outbound interface
from the local Forwarding Information Base (FIB). For a TACACS+
server located in a Virtual Private Network (VPN), a VPN Routing and
Forwarding (VRF) instance needs to be specified.
The 'statistics' container under the 'server' list is a collection of
read-only counters for sent and received messages from a configured
server.
The YANG module for TACACS+ client has the structure shown in
Figure 1.
augment /sys:system:
+--rw tacacs-plus
+--rw client-credentials* [id] {credential-reference}?
| +--rw id string
| +--rw (auth-type)?
| +--:(certificate)
| | ...
| +--:(raw-public-key) {tlsc:client-ident-raw-public-key}?
| | ...
| +--:(tls13-epsk) {tlsc:client-ident-tls13-epsk}?
| ...
+--rw server-credentials* [id] {credential-reference}?
| +--rw id string
| +--rw ca-certs!
| | ...
| +--rw ee-certs!
| | ...
| +--rw raw-public-keys! {tlsc:server-auth-raw-public-key}?
| | ...
| +--rw tls13-epsks? empty
| {tlsc:server-auth-tls13-epsk}?
+--rw server* [name]
+--rw name string
+--rw server-type
| tacacs-plus-server-type
+--rw domain-name? inet:domain-name
+--rw sni-enabled? boolean
+--rw address inet:host
+--rw port inet:port-number
+--rw (security)
| +--:(tls)
| | +--rw client-identity!
| | | +--rw (ref-or-explicit)?
| | | +--:(ref)
| | | | +--rw credentials-reference?
| | | | sys-tcs-plus:client-credentials-ref
| | | | {credential-reference}?
| | | +--:(explicit)
| | | +--rw (auth-type)?
| | | +--:(certificate)
| | | | ...
| | | +--:(raw-public-key)
| | | | {tlsc:client-ident-raw-public-key}?
| | | | ...
| | | +--:(tls13-epsk)
| | | {tlsc:client-ident-tls13-epsk}?
| | | ...
| | +--rw server-authentication
| | | +--rw (ref-or-explicit)?
| | | +--:(ref)
| | | | +--rw credentials-reference?
| | | | sys-tcs-plus:server-credentials-ref
| | | | {credential-reference}?
| | | +--:(explicit)
| | | +--rw ca-certs!
| | | | ...
| | | +--rw ee-certs!
| | | | ...
| | | +--rw raw-public-keys!
| | | | {tlsc:server-auth-raw-public-key}?
| | | | ...
| | | +--rw tls13-epsks? empty
| | | {tlsc:server-auth-tls13-epsk}
| | +--rw hello-params {tlscmn:hello-params}?
| | +--rw tls-versions
| | | +--rw min? identityref
| | | +--rw max? identityref
| | +--rw cipher-suites
| | +--rw cipher-suite*
| | tlscsa:tls-cipher-suite-algorithm
| +--:(obfuscation)
| +--rw shared-secret? string
+--rw (source-type)?
| +--:(source-ip)
| | +--rw source-ip? inet:ip-address
| +--:(source-interface)
| +--rw source-interface? if:interface-ref
+--rw vrf-instance?
| -> /ni:network-instances/network-instance/name
+--rw single-connection? boolean
+--rw timeout? uint16
+--ro statistics
+--ro discontinuity-time? yang:date-and-time
+--ro connection-opens? yang:counter64
+--ro connection-closes? yang:counter64
+--ro connection-aborts? yang:counter64
+--ro connection-failures? yang:counter64
+--ro connection-timeouts? yang:counter64
+--ro messages-sent? yang:counter64
+--ro messages-received? yang:counter64
+--ro errors-received? yang:counter64
+--ro sessions? yang:counter64
+--ro cert-errors? yang:counter64
+--ro rpk-errors? yang:counter64
{tlsc:server-auth-raw-public-key}?
Figure 1: Tree Structure Overview
Specifically, the module is designed to cover the following key
requirements specified in [I-D.ietf-opsawg-tacacs-tls13]: [RFC9887]:
* Minimum TLS 1.3 [RFC8446] MUST be used for transport.
* Earlier TLS versions MUST NOT be used.
* The cipher suites offered or accepted SHOULD be configurable.
* Implementations MAY support Raw Public Keys (RPKs) and Pre-Shared
Keys (PSKs).
* Implementations MUST support the ability to configure the server's
domain name, so that it may be included in the TLS Server Name
Indication (SNI) extension.
The following new data nodes are supported compared to [RFC9105]:
'client-credentials' and 'server-credentials': Defines Define a set
credentials that can be globally provisioned and then referenced
under specific servers.
'domain-name': Provides a domain name of the server per Section 3.3
of [I-D.ietf-opsawg-tacacs-tls13]. [RFC9887]. This is the TLS TACACS+ server's domain name that
is included in the SNI extension. This domain name is distinct
from the IP address/hostname used for the underlying transport
connection.
'sni-enabled': Controls activation of Server Name Indication (SNI) SNI (Section 3 of [RFC6066]).
This parameter can be used only if a domain name is provided.
'client-identity': Specifies the identity credentials that the
client may present when establishing a connection to a server.
Client identities can be configured at the top level and then
referenced for specific server instances. Alternatively, client
identities can be configured explicitly under each server
instance.
'server-authentication': Specifies how a client authenticates
servers. Server credentials can be configured at the top level
and then referenced for specific server instances. Alternatively,
client identities can be configured explicitly under each server
instance.
'hello-params': Controls TLS versions and cipher suites to be used
when establishing TLS sessions.
'discontinuity-time': The time of the most recent occasion at which
the client suffered a discontinuity (a configuration action to
reset all counters, re-initialization, etc.).
'cert-errors': Number of connection failures due to certificate
issues.
'rpk-errors': Number of connection failures related to raw public key related connection failures.
keys.
4. TACACS+ Client Module
This YANG module uses types and groupings defined in [RFC6991],
[RFC8341], [RFC8343], [RFC8529], [RFC9640], [RFC9641], [RFC9642], and
[RFC9645].
The module augments [RFC7317].
The module also cites [RFC6520], [RFC9257], and [RFC9258].
<CODE BEGINS> file "ietf-system-tacacs-plus@2025-01-23.yang" "ietf-system-tacacs-plus@2026-03-13.yang"
module ietf-system-tacacs-plus {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-system-tacacs-plus";
prefix sys-tcs-plus;
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-system {
prefix sys;
reference
"RFC 7317: A YANG Data Model for System Management";
}
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
import ietf-interfaces {
prefix if;
reference
"RFC 8343: A YANG Data Model for Interface Management";
}
import ietf-network-instance {
prefix ni;
reference
"RFC 8529: YANG Data Model for Network Instances";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC 9640: YANG Data Types and Groupings for Cryptography";
}
import ietf-truststore {
prefix ts;
reference
"RFC 9641: A YANG Data Model for a Truststore";
}
import ietf-keystore {
prefix ks;
reference
"RFC 9642: A YANG Data Model for a Keystore";
}
import ietf-tls-common {
prefix tlscmn;
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
import ietf-tls-client {
prefix tlsc;
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
organization
"IETF OPSAWG (Operations and Management Area Working Group)";
contact
"WG Web: <https://datatracker.ietf.org/wg/opsawg/>
WG List: <mailto:opsawg@ietf.org>
Editor: Mohamed Boucadair
<mailto:mohamed.boucadair@orange.com>
Author: Bo Wu
<lana.wubo@huawei.com>
Author: Guangying Zheng
<zhengguangying@huawei.com>";
description
"This module provides management of TACACS+ clients.
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 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.
Copyright (c) 2025 2026 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Revised BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
All revisions of IETF and IANA published modules can be found
at the YANG Parameters registry
(https://www.iana.org/assignments/yang-parameters).
This version of this YANG module is part of RFC XXXX; 9950; see the
RFC itself for full legal notices.";
revision 2025-01-23 2026-03-13 {
description
"This revision adds TLS support. Specifically, this revision
adds:
- a new feature 'credential-reference'
- a new container 'client-credentials'
- a new container 'server-credentials'
- a new leaf 'domain-name'
- a new leaf 'sni-enabled'
- TLS as a new security choice
- a new leaf 'discontinuity-time' under 'statistics'
- a new leaf 'cert-errors' under 'statistics'
- a new leaf 'rpk-errors' under 'statistics'
Also, this revision:
- updates the reference of for 'tacacs-plus' identity
to also cite RFC SSSS 9887
- fixes a must 'must' statement under 'tacacs-plus' by adding
a missing prefix
- requires that the servers list of servers must be unique per
address/port number.
- updates the description of the 'name' under 'server'
list to better reflect the intended use and clarifies
the difference with the new domain-name
- updates the description of the 'address' to be
consistent with the type
- removes the default statement for the 'port' under
'server' list because a distinct default port number
is used for TACACS+TLS
- updates the 'port' leaf under 'server' list to enumerate
the various TACACS+ default port numbers
- added adds a constraint on the VRF with 'source-interface'
is also provided
- updates the description of timeout to remove redundant
text with the default statement";
reference
"RFC XXXX: 9950: A YANG Data Model for Terminal Access Controller
Access-Control System Plus (TACACS+)";
}
revision 2021-08-05 {
description
"Initial revision.";
reference
"RFC 9105: A YANG Data Model for Terminal Access Controller
Access-Control System Plus (TACACS+)";
}
feature credential-reference {
description
"Indicates whether service credentials references are
supported.";
}
identity tacacs-plus {
base sys:authentication-method;
description
"Indicates AAA operation using TACACS+.";
reference
"RFC SSSS: 9887: Terminal Access Controller Access-Control
System Plus (TACACS+) over TLS 1.3
RFC 8907: The TACACS+ Protocol";
}
typedef tacacs-plus-server-type {
type bits {
bit authentication {
description
"Indicates that the TACACS+ server is providing
authentication services.";
}
bit authorization {
description
"Indicates that the TACACS+ server is providing
authorization services.";
}
bit accounting {
description
"Indicates that the TACACS+ server is providing accounting
services.";
}
}
description
"The type can be set to authentication, authorization,
accounting, or any combination of the three types.";
}
typedef client-credentials-ref {
type leafref {
path "/sys:system/sys-tcs-plus:tacacs-plus"
+ "/sys-tcs-plus:client-credentials/sys-tcs-plus:id";
}
description
"Defines a type to reference client credentials.";
}
typedef server-credentials-ref {
type leafref {
path "/sys:system/sys-tcs-plus:tacacs-plus"
+ "/sys-tcs-plus:server-credentials/sys-tcs-plus:id";
}
description
"Defines a type to reference server credentials.";
}
grouping statistics {
description
"Grouping for TACACS+ statistics attributes, including TLS
specifics.";
container statistics {
config false;
description
"A collection of server-related statistics objects.";
leaf discontinuity-time {
type yang:date-and-time;
description
"The time on of the most recent occasion at which the
TACACS+ client suffered a discontinuity. Examples of
discontinuity can be a configuration action to reset
all counters, re-initialization of the system, or any
other events that prevent reliable contiguous tracking
of counters.";
}
leaf connection-opens {
type yang:counter64;
description
"Number of new connection requests sent to the server,
e.g., socket open.";
}
leaf connection-closes {
type yang:counter64;
description
"Number of connection close requests sent to the server,
e.g., socket close.";
}
leaf connection-aborts {
type yang:counter64;
description
"Number of aborted connections to the server. These do
not include connections that are closed gracefully.";
}
leaf connection-failures {
type yang:counter64;
description
"Number of connection failures to the server.";
}
leaf connection-timeouts {
type yang:counter64;
description
"Number of connection timeouts to the server.";
}
leaf messages-sent {
type yang:counter64;
description
"Number of messages sent to the server.";
}
leaf messages-received {
type yang:counter64;
description
"Number of messages received from the server.";
}
leaf errors-received {
type yang:counter64;
description
"Number of error messages received from the server.";
}
leaf sessions {
type yang:counter64;
description
"Number of TACACS+ sessions completed with the server.
If the Single Connection Mode was not enabled, the number
of sessions is the same as the number of
'connection-closes'. If the Single Connection Mode was
enabled, a single TCP connection may contain multiple
TACACS+ sessions.";
}
leaf cert-errors {
type yang:counter64;
description
"Number of connection failures due to certificate
issues.";
}
leaf rpk-errors {
if-feature "tlsc:server-auth-raw-public-key";
type yang:counter64;
description
"Number of RPK-related connection failures.";
}
}
}
grouping certificate {
description
"Specifies a certificate that can be used for client
identity.";
uses "ks:inline-or-keystore-end-entity-cert-with-key-"
+ "grouping" {
refine "inline-or-keystore/inline/inline-definition" {
must 'not(public-key-format) or derived-from-or-self'
+ '(public-key-format, "ct:subject-public-key-'
+ 'info-format")';
}
refine "inline-or-keystore/central-keystore/"
+ "central-keystore-reference/asymmetric-key" {
must 'not(deref(.)/../ks:public-key-format) or '
+ 'derived-from-or-self(deref(.)/../ks:public-'
+ 'key-format, "ct:subject-public-key-info-'
+ 'format")';
}
}
}
grouping raw-private-key {
description
"Specifies raw private key (RPK) that can be used for
client identity.";
uses ks:inline-or-keystore-asymmetric-key-grouping {
refine "inline-or-keystore/inline/inline-definition" {
must 'not(public-key-format) or derived-from-or-self'
+ '(public-key-format, "ct:subject-public-key-'
+ 'info-format")';
}
refine "inline-or-keystore/central-keystore/"
+ "central-keystore-reference" {
must 'not(deref(.)/../ks:public-key-format) or '
+ 'derived-from-or-self(deref(.)/../ks:public-'
+ 'key-format, "ct:subject-public-key-info-format")';
}
}
}
grouping tls13-epsk {
description
"An External Pre-Shared Key (EPSK) is established or
provisioned out-of-band, out of band, i.e., not from a TLS connection.
An EPSK is a tuple of (Base Key, External Identity, Hash).
When Pre-Shared Keys (PSKs) are provisioned out of band,
the PSK identity and the Key Derivation Function (KDF) hash
algorithm to be used with the PSK must also be
provisioned.";
reference
"RFC 8446: The Transport Layer Security (TLS) Protocol
Version 1.3, Section 4.2.11
RFC 9257: Guidance for External Pre-Shared Key (PSK) Usage
in TLS, Section 6
RFC 9258: Importing External Pre-Shared Keys (PSKs) for
TLS 1.3, Section 5.1";
uses ks:inline-or-keystore-symmetric-key-grouping;
leaf external-identity {
type string;
mandatory true;
description
"A sequence of bytes used to identify an EPSK. A label for
a pre-shared key PSK established externally.";
reference
"RFC 8446: The Transport Layer Security (TLS) Protocol
Version 1.3, Section 4.2.11
RFC 9257: Guidance for External Pre-Shared Key (PSK)
Usage in TLS, Section 4.1";
}
leaf hash {
type tlscmn:epsk-supported-hash;
default "sha-256";
description
"For externally established PSKs, the Hash algorithm must be
set when the PSK is established or default to SHA-256 if no
such algorithm is defined.";
reference
"RFC 8446: The Transport Layer Security (TLS) Protocol
Version 1.3, Section 4.2.11";
}
leaf context {
type string;
description
"The context used to determine the EPSK, if any exists. For
example, context may include information about peer roles or
identities to mitigate Selfie-style reflection attacks.";
reference
"RFC 9258: Importing External Pre-Shared Keys (PSKs) for
TLS 1.3, Section 5.1 ";
}
leaf target-protocol {
type uint16;
description
"Specifies the protocol for which a PSK is imported for
use.";
reference
"RFC 9258: Importing External Pre-Shared Keys (PSKs) for
TLS 1.3, Section 3 ";
}
leaf target-kdf {
type uint16;
description
"The KDF for which a PSK is imported for use.";
reference
"RFC 9258: Importing External Pre-Shared Keys (PSKs) for
TLS 1.3, Section 3";
}
}
grouping client-identity {
description
"Identity credentials that a TLS client may present when
establishing a connection to a TLS server. When configured, configured
and requested by the TLS server when establishing a TLS
session, these credentials are passed in the Certificate
message.";
reference
"RFC 8446: The Transport Layer Security (TLS) Protocol
Version 1.3, Section 4.4.2";
choice auth-type {
description
"A choice amongst authentication types.";
case certificate {
container certificate {
description
"Specifies the client identity using a certificate.";
uses certificate;
}
}
case raw-public-key {
if-feature "tlsc:client-ident-raw-public-key";
container raw-private-key {
description
"Specifies the client identity using RPK.";
uses raw-private-key;
}
}
case tls13-epsk {
if-feature "tlsc:client-ident-tls13-epsk";
container tls13-epsk {
description
"An EPSK is established or provisioned out-of-band."; out of band.";
uses tls13-epsk;
}
}
}
}
grouping client-identity-with-ref {
description
"Identity credentials that the TLS client may present when
establishing a connection to a TLS server. When configured, configured
and requested by the TLS server when establishing a TLS
session, these credentials are passed in the Certificate
message.";
choice ref-or-explicit {
description
"A choice between a reference or explicit configuration.";
case ref {
description
"Provides a reference to a client identity.";
leaf credentials-reference {
if-feature "credential-reference";
type sys-tcs-plus:client-credentials-ref;
description
"Specifies the client credentials reference.";
}
}
case explicit {
description
"Explicit configuration of the client identity.";
uses client-identity;
}
}
}
grouping server-authentication {
description
"Specifies how a TLS client can authenticate TLS servers.
Any combination of credentials is additive and unordered.";
container ca-certs {
presence "Indicates that Certification Authority (CA)
certificates have been configured.
This statement is present so the mandatory descendant
nodes do not imply that this node must be
configured.";
description
"A set of CA certificates used by the TLS client to
authenticate TLS server certificates.
A server certificate is authenticated if it has a valid
chain of trust to a configured CA certificate.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-certs-grouping;
}
container ee-certs {
presence "Indicates that End Entity (EE) certificates have been
configured.
This statement is present so the mandatory descendant
nodes do not imply that this node must be
configured.";
description
"A set of server certificates (i.e., end entity certificates)
used by a TLS client to authenticate certificates
presented by TLS servers. A server certificate is
authenticated if it is an exact match to a configured server
certificate.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-certs-grouping;
}
container raw-public-keys {
if-feature "tlsc:server-auth-raw-public-key";
presence "Indicates that raw public keys have been configured.
This statement is present so the mandatory descendant
nodes do not imply that this node must be
configured.";
description
"A set of raw public keys used by a TLS client to
authenticate raw public keys presented by the TLS server.
A raw public key is authenticated if it is an exact match
to a configured raw public key.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-public-keys-grouping {
refine "inline-or-truststore/inline/inline-definition/"
+ "public-key" {
must 'derived-from-or-self(public-key-format,'
+ ' "ct:subject-public-key-info-format")';
}
refine "inline-or-truststore/central-truststore/"
+ "central-truststore-reference" {
must 'not(deref(.)/../ts:public-key/ts:public-key-'
+ 'format[not(derived-from-or-self(., "ct:subject-'
+ 'public-key-info-format"))])';
}
}
}
leaf tls13-epsks {
if-feature "tlsc:server-auth-tls13-epsk";
type empty;
description
"Indicates that a TLS client can authenticate TLS servers
using configured EPSKs.";
}
}
grouping server-authentication-with-ref {
description
"Specifies how a TLS client can authenticate TLS servers.";
choice ref-or-explicit {
description
"A choice between a reference of or explicit configuration.";
case ref {
description
"Provides a reference to server credentials.";
leaf credentials-reference {
if-feature "credential-reference";
type sys-tcs-plus:server-credentials-ref;
description
"Specifies the server credentials reference.";
}
}
case explicit {
description
"Explicit configuration of credentials of a server.";
uses server-authentication;
}
}
}
grouping hello-params {
description
"Configurable parameters for the TLS Hello message.";
reference
"RFC SSSS: 9887: Terminal Access Controller Access-Control
System Plus (TACACS+) over TLS 1.3,
Section 5.1";
uses tlscmn:hello-params-grouping {
refine "tls-versions/min" {
must "not(derived-from-or-self(current(), "
+ "'tlscmn:tls12'))" {
error-message
"TLS 1.2 is not supported as min TLS version";
}
}
refine "tls-versions/max" {
must "not(derived-from-or-self(current(), "
+ "'tlscmn:tls12'))" {
error-message
"TLS 1.2 is not supported as max TLS version";
}
}
}
}
grouping tls-client {
description
"A grouping for configuring a TLS client without any
consideration for how an underlying TCP session is
established.";
container client-identity {
presence "Indicates that a TLS-level client identity has been
configured.
This statement is present so the mandatory descendant
do not imply that this node must be configured.";
description
"Identity credentials that a TLS client may present when
establishing a connection to a TLS server.";
uses client-identity-with-ref;
}
container server-authentication {
must 'credentials-reference or ca-certs or ee-certs or '
+ 'raw-public-keys or tls13-epsks';
description
"Specifies how a TLS client can authenticate TLS servers.";
uses server-authentication-with-ref;
}
container hello-params {
if-feature "tlscmn:hello-params";
description
"Configurable parameters for the TLS Hello message.";
uses hello-params;
}
}
grouping tacacs-plus {
description
"Grouping for TACACS+ attributes.";
container tacacs-plus {
must "not(derived-from-or-self(../sys:authentication"
+ "/sys:user-authentication-order, "
+ "'sys-tcs-plus:tacacs-plus'))"
+ " or bit-is-set(server/server-type,'authentication')" {
error-message
"When 'tacacs-plus' is used as a system authentication
method, a TACACS+ authentication server must be
configured.";
description
"When 'tacacs-plus' is used as an authentication method,
a TACACS+ server must be configured.";
}
description
"Container for TACACS+ configurations and operations.";
list client-credentials {
if-feature "credential-reference";
key "id";
description
"Identity credentials that a TLS client may present
when establishing a connection to a TLS server.
A list of client credentials that can be referenced
when configuring server instances.";
nacm:default-deny-write;
leaf id {
type string;
description
"An identifier that uniquely identifies a client
identity within the device configuration.";
}
uses client-identity;
}
list server-credentials {
if-feature "credential-reference";
key "id";
description
"Identity credentials that a TLS client may use
to authenticate a TLS server.";
nacm:default-deny-write;
leaf id {
type string;
description
"An identifier that uniquely identify identifies server
credentials within the device configuration.";
}
uses server-authentication;
}
list server {
key "name";
unique "address port";
ordered-by user;
description
"List of TACACS+ servers used by the device.";
leaf name {
type string;
description
"A name that is used to uniquely identify a TACACS+
server within the device configuration.
This name is not to be confused with the domain-name.";
}
leaf server-type {
type tacacs-plus-server-type;
mandatory true;
description
"Server type: authentication/authorization/accounting and
various combinations.";
}
leaf domain-name {
type inet:domain-name;
description
"Provides a domain name of the TACACS+ server.";
reference
"RFC SSSS: 9887: Terminal Access Controller Access-Control
System Plus (TACACS+) over TLS 1.3,
Section 3.4.2";
}
leaf sni-enabled {
type boolean;
must '../domain-name' {
error-message
"A domain name must be provided to make use of Server
Name Indication (SNI).";
}
description
"Enables the use of SNI, SNI when set to true. Disables the
use of SNI, SNI when set to false.";
reference
"RFC 6066: Transport Layer Security (TLS) Extensions:
Extension Definitions, Section 3
RFC SSSS: 9887: Terminal Access Controller Access-Control
System Plus (TACACS+) over TLS 1.3,
Section 3.4.2";
}
leaf address {
type inet:host;
mandatory true;
description
"The IP address or name of the TACACS+ server.";
}
leaf port {
type inet:port-number;
mandatory true;
description
"The port number of the TACACS+ server.
Default
The default port number for legacy TACACS+ is 49,
while it is TBD 300 for TACACS+TLS.";
}
choice security {
mandatory true;
description
"Security mechanism between TACACS+ client and server.";
case tls {
description
"TLS is used to secure TACACS+ exchanges.";
reference
"RFC SSSS: 9887: Terminal Access Controller Access-Control
System Plus (TACACS+) over TLS 1.3";
uses tls-client;
}
case obfuscation {
leaf shared-secret {
type string {
length "1..max";
}
description
"The shared secret, which is known to both the
TACACS+ client and server. TACACS+ server
administrators SHOULD configure a shared secret with
a minimum length of 16 characters.
It is highly recommended that this shared secret is
at least 32 characters long and sufficiently complex
with a mix of different character types,
i.e., upper case, lower case, numeric, and
punctuation. Note that this security mechanism is
best described as 'obfuscation' and not 'encryption'
as it does not provide any meaningful integrity,
privacy, or replay protection.
The use of obfuscation is deprecated in favor
of TLS.
This choice is provided in the model to accommodate
installed base.";
reference
"RFC 8907: The TACACS+ Protocol
RFC SSSS: 9887: Terminal Access Controller Access-Control
System Plus (TACACS+) over TLS 1.3";
nacm:default-deny-all;
}
}
}
choice source-type {
description
"The source address type for outbound TACACS+ packets.";
case source-ip {
leaf source-ip {
type inet:ip-address;
description
"Specifies the source IP address for TACACS+ outbound
packets.";
}
}
case source-interface {
leaf source-interface {
type if:interface-ref;
description
"Specifies the interface from which the IP address
is derived for use as the source for outbound
TACACS+ packets.";
}
}
}
leaf vrf-instance {
type leafref {
path "/ni:network-instances/ni:network-instance/ni:name";
}
must "(not(../source-interface)) or "
+ "(current() = /if:interfaces/if:interface"
+ "[if:name = current()/../source-interface]"
+ "/ni:bind-ni-name)" {
error-message
"VRF instance must match the network instance of the
source interface.";
}
description
"Specifies the VPN Routing and Forwarding (VRF) instance
to use to communicate with the TACACS+ server.
If 'source-interface' is configured, this value MUST
match the network instance bound to the source interface
(via bind-ni-name).";
reference
"RFC 8529: YANG Data Model for Network Instances";
}
leaf single-connection {
type boolean;
default "false";
description
"Indicates whether the Single Connection Mode is enabled
for the server.";
reference
"RFC 8907: The TACACS+ Protocol, Section 4.3";
}
leaf timeout {
type uint16 {
range "1..max";
}
units "seconds";
default "5";
description
"The number of seconds that the device will wait for a
response from each TACACS+ server before trying with a
different server.";
}
uses statistics;
}
}
}
augment "/sys:system" {
description
"Augments the system model with the tacacs-plus data nodes.";
uses tacacs-plus;
}
}
<CODE ENDS>
5. Operational Considerations
The same operational considerations discussed in Section 6 of
[I-D.ietf-opsawg-tacacs-tls13]
[RFC9887] apply for this document.
6. Security Considerations
This section is modeled after the template described in Section 3.7 3.7.1
of [I-D.ietf-netmod-rfc8407bis]. [RFC9907].
The "ietf-ac-common" YANG module defines a data model that is
designed to be accessed via YANG-based management protocols, such as
NETCONF
the Network Configuration Protocol (NETCONF) [RFC6241] and RESTCONF
[RFC8040]. These YANG-based management protocols (1) have to use a
secure transport layer (e.g.,
SSH Secure Shell (SSH) [RFC4252], TLS
[RFC8446], and QUIC [RFC9000]) and (2) have to use mutual
authentication.
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content.
There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., "config true", which is the
default). All writable data nodes are likely to be sensitive or
vulnerable in some network environments. Write operations (e.g.,
edit-config) and delete operations to these data nodes without proper
protection or authentication can have a negative effect on network
operations. The following subtrees and data nodes have particular
sensitivities/vulnerabilities:
'server': This list contains the data nodes used to control the
TACACS+ servers used by the device. Unauthorized access to this
list could enable an attacker to assume complete control over the
device by pointing to a compromised TACACS+ server, or to modify
the counters to hide attacks against the device.
'shared-secret': This leaf controls the key known to both the
TACACS+ client and server. Unauthorized access to this leaf could
make the device vulnerable to attacks; therefore, it has been
restricted using the "default-deny-all" access control defined in
[RFC8341]. When setting, it is highly recommended that the leaf
is at least 32 characters long and sufficiently complex with a mix
of different character types, i.e., upper case, lower case,
numeric, and punctuation.
'client-identity' and 'server-authentication': Any modification to a
key or reference to a key may dramatically alter the implemented
security policy. For this reason, the NACM extension "default-
deny-write" has been set.
There are no particularly sensitive readable data nodes.
There are no particularly sensitive RPC or action operations.
This YANG module uses groupings from other YANG modules that define
nodes that may be considered sensitive or vulnerable in network
environments. Refer to Section 5.3 of [RFC9642] and Section 5.3 of
[RFC9645] for information as to which nodes may be considered
sensitive or vulnerable in network environments.
7. IANA Considerations
IANA is requested to update has registered the following URI in the "ns" subregistry registry within the
"IETF XML Registry" [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-system-tacacs-plus
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
IANA is requested to register has registered the following YANG module in the "YANG Module
Names" registry [RFC6020] within the "YANG Parameters" registry
group:
Name: ietf-system-tacacs-plus
Namespace: urn:ietf:params:xml:ns:yang:ietf-system-tacacs-plus
Prefix: sys-tcs-plus
Maintained by IANA? N
Namespace: urn:ietf:params:xml:ns:yang:ietf-system-tacacs-plus
Prefix: sys-tcs-plus
Reference: RFC XXXX 9950
8. References
8.1. Normative References
[I-D.ietf-opsawg-tacacs-tls13]
Dahm, T., Heasley, J., dcmgash@cisco.com, and A. Ota,
"Terminal Access Controller Access-Control System Plus
over TLS 1.3 (TACACS+ over TLS)", Work in Progress,
Internet-Draft, draft-ietf-opsawg-tacacs-tls13-23, 21 June
2025, <https://datatracker.ietf.org/doc/html/draft-ietf-
opsawg-tacacs-tls13-23>.
[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/rfc/rfc2119>.
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/rfc/rfc3688>.
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/rfc/rfc6020>.
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
Extensions: Extension Definitions", RFC 6066,
DOI 10.17487/RFC6066, January 2011,
<https://www.rfc-editor.org/rfc/rfc6066>.
<https://www.rfc-editor.org/info/rfc6066>.
[RFC6520] Seggelmann, R., Tuexen, M., and M. Williams, "Transport
Layer Security (TLS) and Datagram Transport Layer Security
(DTLS) Heartbeat Extension", RFC 6520,
DOI 10.17487/RFC6520, February 2012,
<https://www.rfc-editor.org/rfc/rfc6520>.
<https://www.rfc-editor.org/info/rfc6520>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/rfc/rfc6991>.
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for
System Management", RFC 7317, DOI 10.17487/RFC7317, August
2014, <https://www.rfc-editor.org/rfc/rfc7317>. <https://www.rfc-editor.org/info/rfc7317>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/rfc/rfc7950>.
<https://www.rfc-editor.org/info/rfc7950>.
[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/rfc/rfc8174>. <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/rfc/rfc8341>.
<https://www.rfc-editor.org/info/rfc8341>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/rfc/rfc8342>.
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
<https://www.rfc-editor.org/rfc/rfc8343>.
<https://www.rfc-editor.org/info/rfc8343>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/rfc/rfc8446>.
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8529] Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X.
Liu, "YANG Data Model for Network Instances", RFC 8529,
DOI 10.17487/RFC8529, March 2019,
<https://www.rfc-editor.org/rfc/rfc8529>.
<https://www.rfc-editor.org/info/rfc8529>.
[RFC9257] Housley, R., Hoyland, J., Sethi, M., and C. A. Wood,
"Guidance for External Pre-Shared Key (PSK) Usage in TLS",
RFC 9257, DOI 10.17487/RFC9257, July 2022,
<https://www.rfc-editor.org/rfc/rfc9257>.
<https://www.rfc-editor.org/info/rfc9257>.
[RFC9258] Benjamin, D. and C. A. Wood, "Importing External Pre-
Shared Keys (PSKs) for TLS 1.3", RFC 9258,
DOI 10.17487/RFC9258, July 2022,
<https://www.rfc-editor.org/rfc/rfc9258>.
<https://www.rfc-editor.org/info/rfc9258>.
[RFC9640] Watsen, K., "YANG Data Types and Groupings for
Cryptography", RFC 9640, DOI 10.17487/RFC9640, October
2024, <https://www.rfc-editor.org/rfc/rfc9640>. <https://www.rfc-editor.org/info/rfc9640>.
[RFC9641] Watsen, K., "A YANG Data Model for a Truststore",
RFC 9641, DOI 10.17487/RFC9641, October 2024,
<https://www.rfc-editor.org/rfc/rfc9641>.
<https://www.rfc-editor.org/info/rfc9641>.
[RFC9642] Watsen, K., "A YANG Data Model for a Keystore", RFC 9642,
DOI 10.17487/RFC9642, October 2024,
<https://www.rfc-editor.org/rfc/rfc9642>.
<https://www.rfc-editor.org/info/rfc9642>.
[RFC9645] Watsen, K., "YANG Groupings for TLS Clients and TLS
Servers", RFC 9645, DOI 10.17487/RFC9645, October 2024,
<https://www.rfc-editor.org/rfc/rfc9645>.
<https://www.rfc-editor.org/info/rfc9645>.
[RFC9887] Dahm, T., Heasley, J., Medway Gash, D.C., and A. Ota,
"Terminal Access Controller Access-Control System Plus
(TACACS+) over TLS 1.3", RFC 9887, DOI 10.17487/RFC9887,
December 2025, <https://www.rfc-editor.org/info/rfc9887>.
8.2. Informative References
[I-D.ietf-netmod-rfc8407bis]
Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
Authors and Reviewers of Documents Containing YANG Data
Models", Work in Progress, Internet-Draft, draft-ietf-
netmod-rfc8407bis-28, 5 June 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
rfc8407bis-28>.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, DOI 10.17487/RFC2865, June 2000,
<https://www.rfc-editor.org/rfc/rfc2865>.
<https://www.rfc-editor.org/info/rfc2865>.
[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
January 2006, <https://www.rfc-editor.org/rfc/rfc4252>. <https://www.rfc-editor.org/info/rfc4252>.
[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/rfc/rfc6241>.
<https://www.rfc-editor.org/info/rfc6241>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/rfc/rfc8040>.
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/rfc/rfc8340>.
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8907] Dahm, T., Ota, A., Medway Gash, D.C., Carrel, D., and L.
Grant, "The Terminal Access Controller Access-Control
System Plus (TACACS+) Protocol", RFC 8907,
DOI 10.17487/RFC8907, September 2020,
<https://www.rfc-editor.org/rfc/rfc8907>.
<https://www.rfc-editor.org/info/rfc8907>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/rfc/rfc9000>.
<https://www.rfc-editor.org/info/rfc9000>.
[RFC9105] Wu, B., Ed., Zheng, G., and M. Wang, Ed., "A YANG Data
Model for Terminal Access Controller Access-Control System
Plus (TACACS+)", RFC 9105, DOI 10.17487/RFC9105, August
2021, <https://www.rfc-editor.org/rfc/rfc9105>. <https://www.rfc-editor.org/info/rfc9105>.
[RFC9907] Bierman, A., Boucadair, M., Ed., and Q. Wu, "Guidelines
for Authors and Reviewers of Documents Containing YANG
Data Models", RFC 9907, DOI 10.17487/RFC9907, March 2026,
<https://www.rfc-editor.org/info/rfc9907>.
Appendix A. Example TACACS+ Authentication Configuration with Shared
Secret
Figure 2 shows an example where a TACACS+ authentication server
instance is configured using a shared secret for authentication.
This mode is not recommended per [I-D.ietf-opsawg-tacacs-tls13]. [RFC9887].
{
"ietf-system:system": {
"authentication": {
"user-authentication-order": [
"ietf-system-tacacs-plus:tacacs-plus",
"ietf-system:local-users"
]
},
"ietf-system-tacacs-plus:tacacs-plus": {
"server": [
{
"name": "tac_plus1",
"server-type": "authentication",
"address": "192.0.2.2",
"shared-secret": "QaEfThUkO198010075460923+h3TbE8n",
"source-ip": "192.0.2.12",
"timeout": 10
}
]
}
}
}
Figure 2: Example with Shared Secret
Figure 3 provides an example to associate a TACACS+ server with a
VRF.
{
"ietf-network-instance:network-instances": {
"network-instance": [
{
"name": "MANAGEMENT_VRF",
"description": "Management VRF for TACACS+ traffic isolation"
}
]
},
"ietf-system:system": {
"authentication": {
"user-authentication-order": [
"ietf-system-tacacs-plus:tacacs-plus",
"ietf-system:local-users"
]
},
"ietf-system-tacacs-plus:tacacs-plus": {
"server": [
{
"name": "tac_plus1",
"server-type": "authentication",
"address": "192.0.2.2",
"shared-secret": "QaEfThUkO198010075460923+h3TbE8n",
"source-ip": "192.0.2.12",
"vrf-instance": "MANAGEMENT_VRF",
"timeout": 10
}
]
}
}
}
Figure 3: Example with VRF
Appendix B. TACACS+TLS Examples
This section provides examples to illustrate the configuration of
TACACS+TLS clients.
These examples follow the convention used in Section 1.5 of [RFC9645]
for binary data that has been base64 encoded.
B.1. Example TACACS+ Authentication Configuration with Explicit
Certificate Definitions
Figure 4 shows a configuration example with 'inline-definition' for
the client identity and server authentication.
=============== NOTE: '\' line wrapping per RFC 8792 ================
{
"ietf-system:system": {
"authentication": {
"user-authentication-order": [
"ietf-system-tacacs-plus:tacacs-plus",
"ietf-system:local-users"
]
},
"ietf-system-tacacs-plus:tacacs-plus": {
"server": [
{
"name": "instance-1",
"server-type": "authentication",
"domain-name": "tacacs.example.com",
"sni-enabled": true,
"address": "2001:db8::1",
"port": 1234,
"client-identity": {
"certificate": {
"inline-definition": {
"public-key-format": "ietf-crypto-types:subject-\
public-key-info-format",
"public-key": "BASE64VALUE=",
"private-key-format": "ietf-crypto-types:rsa-private\
-key-format",
"cleartext-private-key": "BASE64VALUE=",
"cert-data": "BASE64VALUE="
}
}
},
"server-authentication": {
"ca-certs": {
"inline-definition": {
"certificate": [
{
"name": "CA-Certificate-1",
"cert-data": "BASE64VALUE="
}
]
}
}
},
"hello-params": {
"tls-versions": {
"min": "ietf-tls-common:tls13",
"max": "ietf-tls-common:tls13"
},
"cipher-suites": {
"cipher-suite": [
"TLS_AES_128_GCM_SHA256"
]
}
},
"single-connection": false,
"timeout": 10
}
]
}
}
}
Figure 4: Example with TACACS+TLS with Inline Certificate Definitions
B.2. Example TACACS+ Authentication Configuration with Certificate
References
Figure 5 shows a configuration example with credential references for
multiple service instances: four instances. Four server instances are configured with configured,
all using the same credentials. These instances form a redundancy
group for both IPv4 and IPv6.
=============== NOTE: '\' line wrapping per RFC 8792 ================
{
"ietf-system:system": {
"ietf-system-tacacs-plus:tacacs-plus": {
"client-credentials": [
{
"id": "client-cred-1",
"certificate": {
"inline-definition": {
"public-key-format": "ietf-crypto-types:subject-public\
-key-info-format",
"public-key": "BASE64VALUE=",
"private-key-format": "ietf-crypto-types:rsa-private-\
key-format",
"cleartext-private-key": "BASE64VALUE=",
"cert-data": "BASE64VALUE="
}
}
}
],
"server-credentials": [
{
"id": "server-cred-1",
"ca-certs": {
"inline-definition": {
"certificate": [
{
"name": "CA-Certificate-1",
"cert-data": "BASE64VALUE="
}
]
}
}
}
],
"server": [
{
"name": "primary-v6",
"server-type": "authentication",
"domain-name": "tacacs.example.com",
"sni-enabled": true,
"address": "2001:db8::1",
"port": 1234,
"client-identity": {
"credentials-reference": "client-cred-1"
},
"server-authentication": {
"credentials-reference": "server-cred-1"
}
},
{
"name": "backup-v6",
"server-type": "authentication",
"domain-name": "tacacs.example.com",
"sni-enabled": true,
"address": "2001:db8::2",
"port": 1234,
"client-identity": {
"credentials-reference": "client-cred-1"
},
"server-authentication": {
"credentials-reference": "server-cred-1"
}
},
{
"name": "primary-v4",
"server-type": "authentication",
"domain-name": "tacacs.example.com",
"sni-enabled": true,
"address": "192.0.2.1",
"port": 49,
"client-identity": {
"credentials-reference": "client-cred-1"
},
"server-authentication": {
"credentials-reference": "server-cred-1"
}
},
{
"name": "backup-v4",
"server-type": "authentication",
"domain-name": "tacacs.example.com",
"sni-enabled": true,
"address": "192.0.2.2",
"port": 49,
"client-identity": {
"credentials-reference": "client-cred-1"
},
"server-authentication": {
"credentials-reference": "server-cred-1"
}
}
]
}
}
}
Figure 5: Example with TACACS+TLS with References
Appendix C. Full Tree
The full tree structure is shown below:
=============== NOTE: '\' line wrapping per RFC 8792 ================
module: ietf-system-tacacs-plus
augment /sys:system:
+--rw tacacs-plus
+--rw client-credentials* [id] {credential-reference}?
| +--rw id string
| +--rw (auth-type)?
| +--:(certificate)
| | +--rw certificate
| | +--rw (inline-or-keystore)
| | +--:(inline) {inline-definitions-supported}?
| | | +--rw inline-definition
| | | +--rw public-key-format?
| | | | identityref
| | | +--rw public-key?
| | | | binary
| | | +--rw private-key-format?
| | | | identityref
| | | +--rw (private-key-type)
| | | | +--:(cleartext-private-key)
| | | | | {cleartext-private-keys}?
| | | | | +--rw cleartext-private-key?
| | | | | binary
| | | | +--:(hidden-private-key)
| | | | | {hidden-private-keys}?
| | | | | +--rw hidden-private-key?
| | | | | empty
| | | | +--:(encrypted-private-key)
| | | | {encrypted-private-keys}?
| | | | +--rw encrypted-private-key
| | | | +--rw encrypted-by
| | | | +--rw encrypted-value-format
| | | | | identityref
| | | | +--rw encrypted-value
| | | | binary
| | | +--rw cert-data?
| | | | end-entity-cert-cms
| | | +---n certificate-expiration
| | | | {certificate-expiration-\
notification}?
| | | | +-- expiration-date
| | | | yang:date-and-time
| | | +---x generate-csr {csr-generation}?
| | | +---w input
| | | | +---w csr-format identityref
| | | | +---w csr-info csr-info
| | | +--ro output
| | | +--ro (csr-type)
| | | +--:(p10-csr)
| | | +--ro p10-csr? p10-csr
| | +--:(central-keystore)
| | {central-keystore-supported,\
asymmetric-keys}?
| | +--rw central-keystore-reference
| | +--rw asymmetric-key?
| | | ks:central-asymmetric-key-ref
| | | {central-keystore-supported,\
asymmetric-keys}?
| | +--rw certificate? leafref
| +--:(raw-public-key) {tlsc:client-ident-raw-public-key}?
| | +--rw raw-private-key
| | +--rw (inline-or-keystore)
| | +--:(inline) {inline-definitions-supported}?
| | | +--rw inline-definition
| | | +--rw public-key-format?
| | | | identityref
| | | +--rw public-key?
| | | | binary
| | | +--rw private-key-format?
| | | | identityref
| | | +--rw (private-key-type)
| | | +--:(cleartext-private-key)
| | | | {cleartext-private-keys}?
| | | | +--rw cleartext-private-key?
| | | | binary
| | | +--:(hidden-private-key)
| | | | {hidden-private-keys}?
| | | | +--rw hidden-private-key?
| | | | empty
| | | +--:(encrypted-private-key)
| | | {encrypted-private-keys}?
| | | +--rw encrypted-private-key
| | | +--rw encrypted-by
| | | +--rw encrypted-value-format
| | | | identityref
| | | +--rw encrypted-value
| | | binary
| | +--:(central-keystore)
| | {central-keystore-supported,\
asymmetric-keys}?
| | +--rw central-keystore-reference?
| | ks:central-asymmetric-key-ref
| +--:(tls13-epsk) {tlsc:client-ident-tls13-epsk}?
| +--rw tls13-epsk
| +--rw (inline-or-keystore)
| | +--:(inline) {inline-definitions-supported}?
| | | +--rw inline-definition
| | | +--rw key-format?
| | | | identityref
| | | +--rw (key-type)
| | | +--:(cleartext-symmetric-key)
| | | | +--rw cleartext-symmetric-key?
| | | | binary
| | | | {cleartext-symmetric-keys}?
| | | +--:(hidden-symmetric-key)
| | | | {hidden-symmetric-keys}?
| | | | +--rw hidden-symmetric-key?
| | | | empty
| | | +--:(encrypted-symmetric-key)
| | | {encrypted-symmetric-keys}?
| | | +--rw encrypted-symmetric-key
| | | +--rw encrypted-by
| | | +--rw encrypted-value-format
| | | | identityref
| | | +--rw encrypted-value
| | | binary
| | +--:(central-keystore)
| | {central-keystore-supported,symmetric\
-keys}?
| | +--rw central-keystore-reference?
| | ks:central-symmetric-key-ref
| +--rw external-identity string
| +--rw hash?
| | tlscmn:epsk-supported-hash
| +--rw context? string
| +--rw target-protocol? uint16
| +--rw target-kdf? uint16
+--rw server-credentials* [id] {credential-reference}?
| +--rw id string
| +--rw ca-certs!
| | +--rw (inline-or-truststore)
| | +--:(inline) {inline-definitions-supported}?
| | | +--rw inline-definition
| | | +--rw certificate* [name]
| | | +--rw name string
| | | +--rw cert-data
| | | | trust-anchor-cert-cms
| | | +---n certificate-expiration
| | | {certificate-expiration-\
notification}?
| | | +-- expiration-date yang:date-and-time
| | +--:(central-truststore)
| | {central-truststore-supported,certificates}?
| | +--rw central-truststore-reference?
| | ts:central-certificate-bag-ref
| +--rw ee-certs!
| | +--rw (inline-or-truststore)
| | +--:(inline) {inline-definitions-supported}?
| | | +--rw inline-definition
| | | +--rw certificate* [name]
| | | +--rw name string
| | | +--rw cert-data
| | | | trust-anchor-cert-cms
| | | +---n certificate-expiration
| | | {certificate-expiration-\
notification}?
| | | +-- expiration-date yang:date-and-time
| | +--:(central-truststore)
| | {central-truststore-supported,certificates}?
| | +--rw central-truststore-reference?
| | ts:central-certificate-bag-ref
| +--rw raw-public-keys! {tlsc:server-auth-raw-public-key}?
| | +--rw (inline-or-truststore)
| | +--:(inline) {inline-definitions-supported}?
| | | +--rw inline-definition
| | | +--rw public-key* [name]
| | | +--rw name string
| | | +--rw public-key-format identityref
| | | +--rw public-key binary
| | +--:(central-truststore)
| | {central-truststore-supported,public-keys}?
| | +--rw central-truststore-reference?
| | ts:central-public-key-bag-ref
| +--rw tls13-epsks? empty
| {tlsc:server-auth-tls13-epsk}?
+--rw server* [name]
+--rw name string
+--rw server-type
| tacacs-plus-server-type
+--rw domain-name? inet:domain-name
+--rw sni-enabled? boolean
+--rw address inet:host
+--rw port inet:port-number
+--rw (security)
| +--:(tls)
| | +--rw client-identity!
| | | +--rw (ref-or-explicit)?
| | | +--:(ref)
| | | | +--rw credentials-reference?
| | | | sys-tcs-plus:client-credentials-ref
| | | | {credential-reference}?
| | | +--:(explicit)
| | | +--rw (auth-type)?
| | | +--:(certificate)
| | | | +--rw certificate
| | | | +--rw (inline-or-keystore)
| | | | +--:(inline)
| | | | | {inline-definitions-\
supported}?
| | | | | +--rw inline-definition
| | | | | +--rw public-key-format?
| | | | | | identityref
| | | | | +--rw public-key?
| | | | | | binary
| | | | | +--rw private-key-format?
| | | | | | identityref
| | | | | +--rw (private-key-type)
| | | | | | +--:(cleartext-private\
-key)
| | | | | | | {cleartext-\
private-keys}?
| | | | | | | +--rw cleartext-\
private-key?
| | | | | | | binary
| | | | | | +--:(hidden-private-\
key)
| | | | | | | {hidden-\
private-keys}?
| | | | | | | +--rw hidden-\
private-key?
| | | | | | | empty
| | | | | | +--:(encrypted-private\
-key)
| | | | | | {encrypted-\
private-keys}?
| | | | | | +--rw encrypted-\
private-key
| | | | | | +--rw encrypted-\
by
| | | | | | +--rw encrypted-\
value-format
| | | | | | | \
identityref
| | | | | | +--rw encrypted-\
value
| | | | | | binary
| | | | | +--rw cert-data?
| | | | | | end-entity-cert-\
cms
| | | | | +---n certificate-\
expiration
| | | | | | {certificate-\
expiration-notification}?
| | | | | | +-- expiration-date
| | | | | | yang:date-and-\
time
| | | | | +---x generate-csr
| | | | | {csr-generation}?
| | | | | +---w input
| | | | | | +---w csr-format
| | | | | | | identityref
| | | | | | +---w csr-info
| | | | | | csr-info
| | | | | +--ro output
| | | | | +--ro (csr-type)
| | | | | +--:(p10-csr)
| | | | | +--ro p10-csr?
| | | | | p10-\
csr
| | | | +--:(central-keystore)
| | | | {central-keystore-\
supported,asymmetric-keys}?
| | | | +--rw central-keystore-\
reference
| | | | +--rw asymmetric-key?
| | | | | ks:central-\
asymmetric-key-ref
| | | | | {central-keystore\
-supported,asymmetric-keys}?
| | | | +--rw certificate?
| | | | leafref
| | | +--:(raw-public-key)
| | | | {tlsc:client-ident-raw-public-\
key}?
| | | | +--rw raw-private-key
| | | | +--rw (inline-or-keystore)
| | | | +--:(inline)
| | | | | {inline-definitions-\
supported}?
| | | | | +--rw inline-definition
| | | | | +--rw public-key-format?
| | | | | | identityref
| | | | | +--rw public-key?
| | | | | | binary
| | | | | +--rw private-key-format?
| | | | | | identityref
| | | | | +--rw (private-key-type)
| | | | | +--:(cleartext-private\
-key)
| | | | | | {cleartext-\
private-keys}?
| | | | | | +--rw cleartext-\
private-key?
| | | | | | binary
| | | | | +--:(hidden-private-\
key)
| | | | | | {hidden-\
private-keys}?
| | | | | | +--rw hidden-\
private-key?
| | | | | | empty
| | | | | +--:(encrypted-private\
-key)
| | | | | {encrypted-\
private-keys}?
| | | | | +--rw encrypted-\
private-key
| | | | | +--rw encrypted-\
by
| | | | | +--rw encrypted-\
value-format
| | | | | | \
identityref
| | | | | +--rw encrypted-\
value
| | | | | binary
| | | | +--:(central-keystore)
| | | | {central-keystore-\
supported,asymmetric-keys}?
| | | | +--rw central-keystore-\
reference?
| | | | ks:central-\
asymmetric-key-ref
| | | +--:(tls13-epsk)
| | | {tlsc:client-ident-tls13-epsk}?
| | | +--rw tls13-epsk
| | | +--rw (inline-or-keystore)
| | | | +--:(inline)
| | | | | {inline-definitions-\
supported}?
| | | | | +--rw inline-definition
| | | | | +--rw key-format?
| | | | | | identityref
| | | | | +--rw (key-type)
| | | | | +--:(cleartext-\
symmetric-key)
| | | | | | +--rw cleartext-\
symmetric-key?
| | | | | | binary
| | | | | | {cleartext-\
symmetric-keys}?
| | | | | +--:(hidden-symmetric-\
key)
| | | | | | {hidden-\
symmetric-keys}?
| | | | | | +--rw hidden-\
symmetric-key?
| | | | | | empty
| | | | | +--:(encrypted-\
symmetric-key)
| | | | | {encrypted-\
symmetric-keys}?
| | | | | +--rw encrypted-\
symmetric-key
| | | | | +--rw encrypted-\
by
| | | | | +--rw encrypted-\
value-format
| | | | | | \
identityref
| | | | | +--rw encrypted-\
value
| | | | | binary
| | | | +--:(central-keystore)
| | | | {central-keystore-\
supported,symmetric-keys}?
| | | | +--rw central-keystore-\
reference?
| | | | ks:central-symmetric\
-key-ref
| | | +--rw external-identity
| | | | string
| | | +--rw hash?
| | | | tlscmn:epsk-supported-hash
| | | +--rw context?
| | | | string
| | | +--rw target-protocol?
| | | | uint16
| | | +--rw target-kdf?
| | | uint16
| | +--rw server-authentication
| | | +--rw (ref-or-explicit)?
| | | +--:(ref)
| | | | +--rw credentials-reference?
| | | | sys-tcs-plus:server-credentials-ref
| | | | {credential-reference}?
| | | +--:(explicit)
| | | +--rw ca-certs!
| | | | +--rw (inline-or-truststore)
| | | | +--:(inline)
| | | | | {inline-definitions-\
supported}?
| | | | | +--rw inline-definition
| | | | | +--rw certificate* [name]
| | | | | +--rw name
| | | | | | string
| | | | | +--rw cert-data
| | | | | | trust-anchor-cert-cms
| | | | | +---n certificate-expiration
| | | | | {certificate-\
expiration-notification}?
| | | | | +-- expiration-date
| | | | | yang:date-and-time
| | | | +--:(central-truststore)
| | | | {central-truststore-\
supported,certificates}?
| | | | +--rw central-truststore-reference?
| | | | ts:central-certificate-bag\
-ref
| | | +--rw ee-certs!
| | | | +--rw (inline-or-truststore)
| | | | +--:(inline)
| | | | | {inline-definitions-\
supported}?
| | | | | +--rw inline-definition
| | | | | +--rw certificate* [name]
| | | | | +--rw name
| | | | | | string
| | | | | +--rw cert-data
| | | | | | trust-anchor-cert-cms
| | | | | +---n certificate-expiration
| | | | | {certificate-\
expiration-notification}?
| | | | | +-- expiration-date
| | | | | yang:date-and-time
| | | | +--:(central-truststore)
| | | | {central-truststore-\
supported,certificates}?
| | | | +--rw central-truststore-reference?
| | | | ts:central-certificate-bag\
-ref
| | | +--rw raw-public-keys!
| | | | {tlsc:server-auth-raw-public-key}?
| | | | +--rw (inline-or-truststore)
| | | | +--:(inline)
| | | | | {inline-definitions-\
supported}?
| | | | | +--rw inline-definition
| | | | | +--rw public-key* [name]
| | | | | +--rw name
| | | | | | string
| | | | | +--rw public-key-format
| | | | | | identityref
| | | | | +--rw public-key
| | | | | binary
| | | | +--:(central-truststore)
| | | | {central-truststore-\
supported,public-keys}?
| | | | +--rw central-truststore-reference?
| | | | ts:central-public-key-bag-\
ref
| | | +--rw tls13-epsks? empty
| | | {tlsc:server-auth-tls13-epsk}?
| | +--rw hello-params {tlscmn:hello-params}?
| | +--rw tls-versions
| | | +--rw min? identityref
| | | +--rw max? identityref
| | +--rw cipher-suites
| | +--rw cipher-suite*
| | tlscsa:tls-cipher-suite-algorithm
| +--:(obfuscation)
| +--rw shared-secret? string
+--rw (source-type)?
| +--:(source-ip)
| | +--rw source-ip? inet:ip-address
| +--:(source-interface)
| +--rw source-interface? if:interface-ref
+--rw vrf-instance?
| -> /ni:network-instances/network-instance/name
+--rw single-connection? boolean
+--rw timeout? uint16
+--ro statistics
+--ro discontinuity-time? yang:date-and-time
+--ro connection-opens? yang:counter64
+--ro connection-closes? yang:counter64
+--ro connection-aborts? yang:counter64
+--ro connection-failures? yang:counter64
+--ro connection-timeouts? yang:counter64
+--ro messages-sent? yang:counter64
+--ro messages-received? yang:counter64
+--ro errors-received? yang:counter64
+--ro sessions? yang:counter64
+--ro cert-errors? yang:counter64
+--ro rpk-errors? yang:counter64
{tlsc:server-auth-raw-public-key}?
Acknowledgments
The document leverages data structures defined in [RFC9645].
Thanks to Joe Clarke and Tom Petch for the review and comments.
Thanks to Reshad Rahman for the yangdoctors review, Tina Tsou for the
opsdir review, Ines Robles for the genart review, and Robert Sparks
for the secdir review.
Thanks Mahesh Jethanandani for the AD review.
Thanks Erik Kline and Éric Vyncke for the IESG review.
Authors of RFC 9105:
Bo Wu Wu, Guangying Zheng Zheng, and Michael Wang were the authors of
[RFC9105].
Acknowledgments from RFC 9105: 9105
The authors wish to thank Alex Campbell, John Heasley, Ebben Aries,
Alan DeKok, Joe Clarke, Tom Petch, Robert Wilton, and many others for
their helpful comments and suggestions.
Authors' Addresses
Mohamed Boucadair (editor)
Orange
Email: mohamed.boucadair@orange.com
Bo Wu
Huawei Technologies
Email: mlana.wubo@huawei.com