<?xml version='1.0' encoding='utf-8'?>
<rfc xmlns:xi="http://www.w3.org/2001/XInclude" version="3" category="std" docName="draft-ietf-netmod-syslog-model-33" number="9742" obsoletes="" updates="" ipr="trust200902" submissionType="IETF" consensus="true" tocInclude="true" symRefs="true" sortRefs="true" xml:lang="en" prepTime="2025-04-30T08:28:41" indexInclude="true" scripts="Common,Latin" tocDepth="3">
  <link href="https://datatracker.ietf.org/doc/draft-ietf-netmod-syslog-model-33" rel="prev"/>
  <link href="https://dx.doi.org/10.17487/rfc9742" rel="alternate"/>
  <link href="urn:issn:2070-1721" rel="alternate"/>
  <front>
    <title abbrev="Syslog Management">A YANG Data Model for Syslog Management</title>
    <seriesInfo name="RFC" value="9742" stream="IETF"/>
    <author fullname="Joe Clarke" initials="J" role="editor" surname="Clarke">
      <organization showOnFrontPage="true">Cisco</organization>
      <address>
        <postal>
          <country>United States of America</country>
        </postal>
        <email>jclarke@cisco.com</email>
      </address>
    </author>
    <author fullname="Mahesh Jethanandani" initials="M" role="editor" surname="Jethanandani">
      <organization showOnFrontPage="true">Kloud Services</organization>
      <address>
        <postal>
          <country>United States of America</country>
        </postal>
        <email>mjethanandani@gmail.com</email>
      </address>
    </author>
    <author fullname="Clyde Wildes" initials="C" role="editor" surname="Wildes">
      <organization showOnFrontPage="true">Cisco Systems Inc.</organization>
      <address>
        <postal>
          <street>170 West Tasman Drive</street>
          <city>San Jose</city>
          <region>CA</region>
          <code>95134</code>
          <country>United States of America</country>
        </postal>
        <phone>+1 415 819-6111</phone>
        <email>clyde@clydewildes.com</email>
      </address>
    </author>
    <author fullname="Kiran Koushik" initials="K" role="editor" surname="Koushik">
      <organization showOnFrontPage="true">Verizon Wireless</organization>
      <address>
        <postal>
          <street>500 W Dove Rd.</street>
          <city>Southlake</city>
          <region>TX</region>
          <code>76092</code>
          <country>United States of America</country>
        </postal>
        <phone>+1 512 650-0210</phone>
        <email>kirankoushik.agraharasreenivasa@verizonwireless.com</email>
      </address>
    </author>
    <date month="04" year="2025"/>
    <area>OPS</area>
    <workgroup>netmod</workgroup>
    <abstract pn="section-abstract">
      <t indent="0" pn="section-abstract-1">
This document defines a YANG data model for the management of a syslog
process. It is intended that this data model be used by vendors who implement
syslog collectors in their systems.
      </t>
    </abstract>
    <boilerplate>
      <section anchor="status-of-memo" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.1">
        <name slugifiedName="name-status-of-this-memo">Status of This Memo</name>
        <t indent="0" pn="section-boilerplate.1-1">
            This is an Internet Standards Track document.
        </t>
        <t indent="0" pn="section-boilerplate.1-2">
            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.
        </t>
        <t indent="0" pn="section-boilerplate.1-3">
            Information about the current status of this document, any
            errata, and how to provide feedback on it may be obtained at
            <eref target="https://www.rfc-editor.org/info/rfc9742" brackets="none"/>.
        </t>
      </section>
      <section anchor="copyright" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.2">
        <name slugifiedName="name-copyright-notice">Copyright Notice</name>
        <t indent="0" pn="section-boilerplate.2-1">
            Copyright (c) 2025 IETF Trust and the persons identified as the
            document authors. All rights reserved.
        </t>
        <t indent="0" pn="section-boilerplate.2-2">
            This document is subject to BCP 78 and the IETF Trust's Legal
            Provisions Relating to IETF Documents
            (<eref target="https://trustee.ietf.org/license-info" brackets="none"/>) 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.
        </t>
      </section>
    </boilerplate>
    <toc>
      <section anchor="toc" numbered="false" removeInRFC="false" toc="exclude" pn="section-toc.1">
        <name slugifiedName="name-table-of-contents">Table of Contents</name>
        <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1">
          <li pn="section-toc.1-1.1">
            <t indent="0" keepWithNext="true" pn="section-toc.1-1.1.1"><xref derivedContent="1" format="counter" sectionFormat="of" target="section-1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-introduction">Introduction</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.1.2">
              <li pn="section-toc.1-1.1.2.1">
                <t indent="0" keepWithNext="true" pn="section-toc.1-1.1.2.1.1"><xref derivedContent="1.1" format="counter" sectionFormat="of" target="section-1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-requirements-language">Requirements Language</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.2">
            <t indent="0" keepWithNext="true" pn="section-toc.1-1.2.1"><xref derivedContent="2" format="counter" sectionFormat="of" target="section-2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-terminology">Terminology</xref></t>
          </li>
          <li pn="section-toc.1-1.3">
            <t indent="0" pn="section-toc.1-1.3.1"><xref derivedContent="3" format="counter" sectionFormat="of" target="section-3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-nmda-compliance">NMDA Compliance</xref></t>
          </li>
          <li pn="section-toc.1-1.4">
            <t indent="0" pn="section-toc.1-1.4.1"><xref derivedContent="4" format="counter" sectionFormat="of" target="section-4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-design-of-the-syslog-model">Design of the Syslog Model</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.4.2">
              <li pn="section-toc.1-1.4.2.1">
                <t indent="0" pn="section-toc.1-1.4.2.1.1"><xref derivedContent="4.1" format="counter" sectionFormat="of" target="section-4.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-syslog-module">Syslog Module</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.5">
            <t indent="0" pn="section-toc.1-1.5.1"><xref derivedContent="5" format="counter" sectionFormat="of" target="section-5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-syslog-yang-module">Syslog YANG Module</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.5.2">
              <li pn="section-toc.1-1.5.2.1">
                <t indent="0" pn="section-toc.1-1.5.2.1.1"><xref derivedContent="5.1" format="counter" sectionFormat="of" target="section-5.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-the-ietf-syslog-module">The ietf-syslog Module</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.6">
            <t indent="0" pn="section-toc.1-1.6.1"><xref derivedContent="6" format="counter" sectionFormat="of" target="section-6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-usage-examples">Usage Examples</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2">
              <li pn="section-toc.1-1.6.2.1">
                <t indent="0" pn="section-toc.1-1.6.2.1.1"><xref derivedContent="6.1" format="counter" sectionFormat="of" target="section-6.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-syslog-configuration-for-se">Syslog Configuration for Severity Critical</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.2">
                <t indent="0" pn="section-toc.1-1.6.2.2.1"><xref derivedContent="6.2" format="counter" sectionFormat="of" target="section-6.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-remote-syslog-configuration">Remote Syslog Configuration</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.7">
            <t indent="0" pn="section-toc.1-1.7.1"><xref derivedContent="7" format="counter" sectionFormat="of" target="section-7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-iana-considerations">IANA Considerations</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.7.2">
              <li pn="section-toc.1-1.7.2.1">
                <t indent="0" pn="section-toc.1-1.7.2.1.1"><xref derivedContent="7.1" format="counter" sectionFormat="of" target="section-7.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-the-ietf-xml-registry">The IETF XML Registry</xref></t>
              </li>
              <li pn="section-toc.1-1.7.2.2">
                <t indent="0" pn="section-toc.1-1.7.2.2.1"><xref derivedContent="7.2" format="counter" sectionFormat="of" target="section-7.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-the-yang-module-names-regis">The YANG Module Names Registry</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.8">
            <t indent="0" pn="section-toc.1-1.8.1"><xref derivedContent="8" format="counter" sectionFormat="of" target="section-8"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-security-considerations">Security Considerations</xref></t>
          </li>
          <li pn="section-toc.1-1.9">
            <t indent="0" pn="section-toc.1-1.9.1"><xref derivedContent="9" format="counter" sectionFormat="of" target="section-9"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-references">References</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.9.2">
              <li pn="section-toc.1-1.9.2.1">
                <t indent="0" pn="section-toc.1-1.9.2.1.1"><xref derivedContent="9.1" format="counter" sectionFormat="of" target="section-9.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-normative-references">Normative References</xref></t>
              </li>
              <li pn="section-toc.1-1.9.2.2">
                <t indent="0" pn="section-toc.1-1.9.2.2.1"><xref derivedContent="9.2" format="counter" sectionFormat="of" target="section-9.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-informative-references">Informative References</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.10">
            <t indent="0" pn="section-toc.1-1.10.1"><xref derivedContent="Appendix A" format="default" sectionFormat="of" target="section-appendix.a"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-tree-diagrams">Tree Diagrams</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.10.2">
              <li pn="section-toc.1-1.10.2.1">
                <t indent="0" pn="section-toc.1-1.10.2.1.1"><xref derivedContent="A.1" format="counter" sectionFormat="of" target="section-appendix.a.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-complete-tree-diagram">Complete Tree Diagram</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.11">
            <t indent="0" pn="section-toc.1-1.11.1"><xref derivedContent="Appendix B" format="default" sectionFormat="of" target="section-appendix.b"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-implementer-guidelines">Implementer Guidelines</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.11.2">
              <li pn="section-toc.1-1.11.2.1">
                <t indent="0" pn="section-toc.1-1.11.2.1.1"><xref derivedContent="B.1" format="counter" sectionFormat="of" target="section-appendix.b.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-extending-facilities">Extending Facilities</xref></t>
              </li>
              <li pn="section-toc.1-1.11.2.2">
                <t indent="0" pn="section-toc.1-1.11.2.2.1"><xref derivedContent="B.2" format="counter" sectionFormat="of" target="section-appendix.b.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-syslog-terminal-output">Syslog Terminal Output</xref></t>
              </li>
              <li pn="section-toc.1-1.11.2.3">
                <t indent="0" pn="section-toc.1-1.11.2.3.1"><xref derivedContent="B.3" format="counter" sectionFormat="of" target="section-appendix.b.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-syslog-file-naming-conventi">Syslog File Naming Convention</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.12">
            <t indent="0" pn="section-toc.1-1.12.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.c"/><xref derivedContent="" format="title" sectionFormat="of" target="name-acknowledgements">Acknowledgements</xref></t>
          </li>
          <li pn="section-toc.1-1.13">
            <t indent="0" pn="section-toc.1-1.13.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.d"/><xref derivedContent="" format="title" sectionFormat="of" target="name-authors-addresses">Authors' Addresses</xref></t>
          </li>
        </ul>
      </section>
    </toc>
  </front>
  <middle>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-1">
      <name slugifiedName="name-introduction">Introduction</name>
      <t indent="0" pn="section-1-1">This document defines a YANG <xref target="RFC7950" format="default" sectionFormat="of" derivedContent="RFC7950"/> data model that
     may be used to configure the syslog feature running on a system.  YANG
     data models can be used with network management protocols such as NETCONF
     <xref target="RFC6241" format="default" sectionFormat="of" derivedContent="RFC6241"/> to install, manipulate, and delete the
     configuration of network devices.</t>
      <t indent="0" pn="section-1-2">The data model makes use of the YANG "feature" construct that allows
     implementations to support only those syslog features that lie within
     their capabilities.</t>
      <t indent="0" pn="section-1-3">
       This module can be used to configure the syslog application
       conceptual layers as implemented on the syslog collector.
      </t>
      <t indent="0" pn="section-1-4">Essentially, a syslog process receives messages (from the kernel,
     processes, applications, or other syslog processes) and processes them.
     The processing may involve logging to a local file, displaying on
     console, and/or relaying to syslog processes on other machines. The
     process is determined by the "facility" that originated the message
     and the "severity" assigned to the message by the facility.</t>
      <t indent="0" pn="section-1-5">Such definitions of syslog protocol are defined in 
     <xref target="RFC5424" format="default" sectionFormat="of" derivedContent="RFC5424"/> and are used in this RFC.</t>
      <t indent="0" pn="section-1-6">The YANG data model in this document conforms to the Network Management
     Datastore Architecture defined in <xref target="RFC8342" format="default" sectionFormat="of" derivedContent="RFC8342"/>.</t>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-1.1">
        <name slugifiedName="name-requirements-language">Requirements Language</name>
        <t indent="0" pn="section-1.1-1">
   The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
   "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>",
   "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
   "<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are
   to be interpreted as described in BCP 14 <xref target="RFC2119" format="default" sectionFormat="of" derivedContent="RFC2119"/>
          <xref target="RFC8174" format="default" sectionFormat="of" derivedContent="RFC8174"/> when, and only when, they appear in all capitals,
   as shown here.
        </t>
      </section>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-2">
      <name slugifiedName="name-terminology">Terminology</name>
      <t indent="0" pn="section-2-1">
   The following terms are used throughout this document:
      </t>
      <dl spacing="normal" newline="false" indent="3" pn="section-2-2">
        <dt pn="section-2-2.1">Originator:</dt>
        <dd pn="section-2-2.2">An "originator" refers to an entity that generates
     syslog content to be carried in a message.  The term is defined
     in <xref target="RFC5424" format="default" sectionFormat="of" derivedContent="RFC5424"/>.</dd>
        <dt pn="section-2-2.3">Relay:</dt>
        <dd pn="section-2-2.4">A "relay" is an entity that forwards syslog messages. It
     accepts messages from originators or other relays and sends them
     to collectors or other relays. The term is defined in <xref target="RFC5424" format="default" sectionFormat="of" derivedContent="RFC5424"/>.</dd>
        <dt pn="section-2-2.5">Collector:</dt>
        <dd pn="section-2-2.6">A "collector" gathers syslog content for
     further analysis. The term is defined in <xref target="RFC5424" format="default" sectionFormat="of" derivedContent="RFC5424"/>.</dd>
        <dt pn="section-2-2.7">Action:</dt>
        <dd pn="section-2-2.8">The term "action" refers to the process that takes
     place for each syslog message received.</dd>
      </dl>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-3">
      <name slugifiedName="name-nmda-compliance">NMDA Compliance</name>
      <t indent="0" pn="section-3-1">The YANG data model in this document conforms to the Network Management
 Datastore Architecture (NMDA) defined in
   <xref target="RFC8342" format="default" sectionFormat="of" derivedContent="RFC8342"/>.
      </t>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-4">
      <name slugifiedName="name-design-of-the-syslog-model">Design of the Syslog Model</name>
      <t indent="0" pn="section-4-1">
   The syslog model was designed by comparing various syslog features
   implemented by various vendors in different implementations.
      </t>
      <t indent="0" pn="section-4-2">
   The module defines leafs that are common across
   implementations. Its simple design is meant to offer maximum
   flexibility. However, not all optional features defined in this
   document are present in all vendor implementations. Therefore, vendors
   need to use the feature statements to specify the
   optional features they support. At the same time, vendors can
   augment the model to add proprietary features. "Extending       
Facilities" (<xref target="extending_facilities" format="default" sectionFormat="of" derivedContent="Appendix B.1"/>) shows an
   example of how that can be realized.
      </t>
      <t indent="0" pn="section-4-3">Syslog consists of originators and collectors. The following diagram
     shows the syslog processing flow from originators to collectors where
     filtering can take place.</t>
      <figure align="left" suppress-title="false" pn="figure-1">
        <name slugifiedName="name-syslog-processing-flow">Syslog Processing Flow</name>
        <artwork name="Syslog Process Flow" align="left" pn="section-4-4.1">
Originators
 +-------------+  +-------------+  +-------------+  +-------------+
 |  Various    |  |     OS      |  |             |  |   Remote    |
 | Components  |  |   Kernel    |  | Line Cards  |  |   Servers   |
 +-------------+  +-------------+  +-------------+  +-------------+

 +-------------+  +-------------+  +-------------+  +-------------+
 |    SNMP     |  |  Interface  |  |   Standby   |  |   Syslog    |
 |   Events    |  |   Events    |  |  Supervisor |  |   Itself    |
 +-------------+  +-------------+  +-------------+  +-------------+

 |                                                                |
 +----------------------------------------------------------------+
              |
              |
              |
              |
      +-------------+--------------+
      |             |              |
      v             v              v
Collectors
 +----------+ +----------+ +----------------+
 |          | |  Log     | |Remote Relay(s)/|
 | Console  | |  File(s) | |Collector(s)    |
 +----------+ +----------+ +----------------+</artwork>
      </figure>
      <t indent="0" pn="section-4-5">Collectors are configured using the leafs in the syslog model
     "actions" container that correspond to each message collector:</t>
      <ul spacing="normal" bare="false" empty="false" indent="3" pn="section-4-6">
        <li pn="section-4-6.1">
          <t indent="0" pn="section-4-6.1.1">console</t>
        </li>
        <li pn="section-4-6.2">
          <t indent="0" pn="section-4-6.2.1">log file(s)</t>
        </li>
        <li pn="section-4-6.3">
          <t indent="0" pn="section-4-6.3.1">remote relay(s)/collector(s)</t>
        </li>
      </ul>
      <t indent="0" pn="section-4-7">Within each action, a selector is used to filter syslog messages.  A
   selector consists of a list of one or more filters specified by
   facility-severity pairs, and, if supported via the select-match
   feature, an optional regular expression pattern match that is
   performed on the MSG field described in <xref target="RFC5424" sectionFormat="of" section="6.4" format="default" derivedLink="https://rfc-editor.org/rfc/rfc5424#section-6.4" derivedContent="RFC5424"/>.</t>
      <sourcecode type="pseudocode" markers="false" pn="section-4-8">
      A syslog message is processed if there is an element
      of facility-list (F, S) where
          the message facility matches F,
          the message severity matches S,
      and/or the message text matches the regex pattern (if it
          is present)</sourcecode>
      <t indent="0" pn="section-4-9">The facility is one of a specific syslog-facility or all
     facilities.</t>
      <t indent="0" pn="section-4-10">
       The model offers the ability to select a transport that a user
       might want to use for a remote relay or collector. The choice
       is between using UDP or TLS-based sessions. The user can
       configure multiple relays or collectors, but they have to use
       the same transport.
      </t>
      <t indent="0" pn="section-4-11">The severity is one of type syslog-severity, all severities, or none.
     None is a special case that can be used to disable a filter. When
     filtering severity, the default comparison is that messages of the
     specified severity and higher are selected to be logged. This is shown
     in the model as "default equals-or-higher". This behavior can be altered
     if the select-adv-compare feature is enabled to specify a compare
     operation and an action. Compare operations are: "equals" to select
     messages with this single severity, or "equals-or-higher" to select
     messages of the specified severity and higher. Actions are used to log
     the message, block the message, or stop the message from being logged.</t>
      <t indent="0" pn="section-4-12">
       Many vendors extend the list of facilities available for
       logging in their implementation. An example is included in "Extending Facilities"
       (<xref target="extending_facilities" format="default" sectionFormat="of" derivedContent="Appendix B.1"/>).
      </t>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-4.1">
        <name slugifiedName="name-syslog-module">Syslog Module</name>
        <t indent="0" pn="section-4.1-1">
   A simplified tree representation of the data model is shown in <xref target="tree-diagram" format="default" sectionFormat="of" derivedContent="Figure 2"/>. Please see <xref target="RFC8340" format="default" sectionFormat="of" derivedContent="RFC8340"/> for tree
   diagram notation.
        </t>
        <figure anchor="tree-diagram" align="left" suppress-title="false" pn="figure-2">
          <name slugifiedName="name-tree-diagram-for-syslog-mod">Tree Diagram for Syslog Model</name>
          <sourcecode type="yangtree" markers="false" pn="section-4.1-2.1">
module: ietf-syslog
 +--rw syslog!
    +--rw actions
       +--rw console! {console-action}?
       |  +--rw filter
       |  |  +--rw facility-list* [facility severity]
       |  |     +--rw facility            union
       |  |     +--rw severity            union
       |  |     +--rw advanced-compare {select-adv-compare}?
       |  |        +--rw compare?   enumeration
       |  |        +--rw action?    identityref
       |  +--rw pattern-match?   string {select-match}?
       +--rw file {file-action}?
       |  +--rw log-file* [name]
       |     +--rw name               inet:uri
       |     +--rw filter
       |     |  +--rw facility-list* [facility severity]
       |     |     +--rw facility            union
       |     |     +--rw severity            union
       |     |     +--rw advanced-compare {select-adv-compare}?
       |     |        +--rw compare?   enumeration
       |     |        +--rw action?    identityref
       |     +--rw pattern-match?     string {select-match}?
       |     +--rw structured-data?   boolean {structured-data}?
       |     +--rw file-rotation
       |        +--rw number-of-files?   uint32 {file-limit-size}?
       |        +--rw max-file-size?     uint32 {file-limit-size}?
       |        +--rw rollover?          uint32
       |        |       {file-limit-duration}?
       |        +--rw retention?         uint32
       |                {file-limit-duration}?
       +--rw remote {remote-action}?
          +--rw destination* [name]
             +--rw name                 string
             +--rw (transport)
             |  +--:(udp)
             |  |  +--rw udp
             |  |     +--rw udp* [address]
             |  |        +--rw address    inet:host
             |  |        +--rw port?      inet:port-number
             |  +--:(tls)
             |     +--rw tls
             |        +--rw tls* [address]
             |           +--rw address                  inet:host
             |           +--rw port?
             |           |       inet:port-number
             |           +--rw client-identity!
             |           |  +--rw (auth-type)
             |           |        ...
             |           +--rw server-authentication
             |           |  +--rw ca-certs! {server-auth-x509-cert}?
             |           |  |     ...
             |           |  +--rw ee-certs! {server-auth-x509-cert}?
             |           |  |     ...
             |           |  +--rw raw-public-keys!
             |           |  |       {server-auth-raw-public-key}?
             |           |  |     ...
             |           |  +--rw tls12-psks?        empty
             |           |  |       {server-auth-tls12-psk}?
             |           |  +--rw tls13-epsks?       empty
             |           |          {server-auth-tls13-epsk}?
             |           +--rw hello-params {tlscmn:hello-params}?
             |           |  +--rw tls-versions
             |           |  |     ...
             |           |  +--rw cipher-suites
             |           |        ...
             |           +--rw keepalives {tls-client-keepalives}?
             |              +--rw peer-allowed-to-send?   empty
             |              +--rw test-peer-aliveness!
             |                    ...
             +--rw filter
             |  +--rw facility-list* [facility severity]
             |     +--rw facility            union
             |     +--rw severity            union
             |     +--rw advanced-compare {select-adv-compare}?
             |        +--rw compare?   enumeration
             |        +--rw action?    identityref
             +--rw pattern-match?       string {select-match}?
             +--rw structured-data?     boolean {structured-data}?
             +--rw facility-override?   identityref
             +--rw source-interface?    if:interface-ref
             |       {remote-source-interface}?
             +--rw signing! {signed-messages}?
                +--rw cert-signers
                   +--rw cert-signer* [name]
                   |  +--rw name              string
                   |  +--rw cert
                   |  |  +--rw public-key-format?
                   |  |  |       identityref
                   |  |  +--rw public-key?                    binary
                   |  |  +--rw private-key-format?
                   |  |  |       identityref
                   |  |  +--rw (private-key-type)
                   |  |  |  +--:(cleartext-private-key)
                   |  |  |  |        {cleartext-private-keys}?
                   |  |  |  |     ...
                   |  |  |  +--:(hidden-private-key)
                   |  |  |  |        {hidden-private-keys}?
                   |  |  |  |     ...
                   |  |  |  +--:(encrypted-private-key)
                   |  |  |           {encrypted-private-keys}?
                   |  |  |        ...
                   |  |  +--rw cert-data?
                   |  |  |       end-entity-cert-cms
                   |  |  +---n certificate-expiration
                   |  |  |       {certificate-expiration-notificati\
on}?
                   |  |  |  +-- expiration-date
                   |  |  |          yang:date-and-time
                   |  |  +---x generate-csr {csr-generation}?
                   |  |     +---w input
                   |  |     |     ...
                   |  |     +--ro output
                   |  |           ...
                   |  +--rw hash-algorithm?   enumeration
                   +--rw cert-initial-repeat?   uint32
                   +--rw cert-resend-delay?     uint32
                   +--rw cert-resend-count?     uint32
                   +--rw sig-max-delay?         uint32
                   +--rw sig-number-resends?    uint32
                   +--rw sig-resend-delay?      uint32
                   +--rw sig-resend-count?      uint32
</sourcecode>
        </figure>
      </section>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-5">
      <name slugifiedName="name-syslog-yang-module">Syslog YANG Module</name>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-5.1">
        <name slugifiedName="name-the-ietf-syslog-module">The ietf-syslog Module</name>
        <t indent="0" pn="section-5.1-1">
   This module imports typedefs from <xref target="RFC6991" format="default" sectionFormat="of" derivedContent="RFC6991"/>, <xref target="RFC8343" format="default" sectionFormat="of" derivedContent="RFC8343"/>, groupings from <xref target="RFC9640" format="default" sectionFormat="of" derivedContent="RFC9640"/>, and <xref target="RFC9645" format="default" sectionFormat="of" derivedContent="RFC9645"/>. It references
   <xref target="RFC5424" format="default" sectionFormat="of" derivedContent="RFC5424"/>, <xref target="RFC5425" format="default" sectionFormat="of" derivedContent="RFC5425"/>, <xref target="RFC5426" format="default" sectionFormat="of" derivedContent="RFC5426"/>, <xref target="RFC5848" format="default" sectionFormat="of" derivedContent="RFC5848"/>, <xref target="RFC8089" format="default" sectionFormat="of" derivedContent="RFC8089"/>, <xref target="RFC8174" format="default" sectionFormat="of" derivedContent="RFC8174"/>, and <xref target="Std-1003.1-2024" format="default" sectionFormat="of" derivedContent="Std-1003.1-2024"/>.
        </t>
        <figure align="left" suppress-title="false" pn="figure-3">
          <name slugifiedName="name-syslog-yang-module-2">Syslog YANG Module</name>
          <sourcecode type="yang" markers="true" name="ietf-syslog@2025-04-30.yang" pn="section-5.1-2.1">
module ietf-syslog {
 yang-version 1.1;
 namespace "urn:ietf:params:xml:ns:yang:ietf-syslog";
 prefix syslog;

 import ietf-inet-types {
   prefix inet;
   reference
     "RFC 6991: Common YANG Data Types";
 }
 import ietf-interfaces {
   prefix if;
   reference
     "RFC 8343: A YANG Data Model for Interface Management";
 }
 import ietf-tls-client {
   prefix tlsc;
   reference
     "RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
 }
 import ietf-crypto-types {
   prefix ct;
   reference
     "RFC 9640: YANG Data Types and Groupings for Cryptography";
 }

 organization
   "IETF NETMOD (Network Modeling) Working Group";
 contact
   "WG Web:   &lt;https://datatracker.ietf.org/wg/netmod/&gt;
    WG List:  &lt;mailto:netmod@ietf.org&gt;

    Editor:   Mahesh Jethanandani
    &lt;mailto:mjethanandani@gmail.com&gt;

    Editor:   Joe Clarke
    &lt;mailto:jclarke@cisco.com&gt;

    Editor:   Kiran Agrahara Sreenivasa
    &lt;mailto:kirankoushik.agraharasreenivasa@verizonwireless.com&gt;

    Editor:   Clyde Wildes
    &lt;mailto:clyde@clydewildes.com&gt;";
 description
   "This module contains a collection of YANG definitions
    for syslog management.

    Copyright (c) 2025 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).

    This version of this YANG module is part of RFC 9742
    (https://www.rfc-editor.org/info/rfc9742);
    see the RFC itself for full legal notices.

    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.";

 revision 2025-04-30 {
   description
     "Initial Revision";
   reference
     "RFC 9742: Syslog YANG Module";
 }

 feature console-action {
   description
     "This feature indicates that the local console action is
      supported.";
 }

 feature file-action {
   description
     "This feature indicates that the local file action is
      supported.";
 }

 feature file-limit-size {
   description
     "This feature indicates that file logging resources
      are managed using size and number limits.";
 }

 feature file-limit-duration {
   description
     "This feature indicates that file logging resources
      are managed using time based limits.";
 }

 feature remote-action {
   description
     "This feature indicates that the remote server action is
      supported.";
 }

 feature remote-source-interface {
   description
     "This feature indicates that source-interface is supported
      for the remote-action.";
 }

 feature select-adv-compare {
   description
     "This feature represents the ability to select messages
      using the additional comparison operators when comparing
      the syslog message severity.";
 }

 feature select-match {
   description
     "This feature represents the ability to select messages
      based on a Posix 1003.2 regular expression pattern
      match.";
 }

 feature structured-data {
   description
     "This feature represents the ability to log messages
      in structured-data format.";
   reference
     "RFC 5424: The Syslog Protocol";
 }

 feature signed-messages {
   description
     "This feature represents the ability to configure signed
      syslog messages.";
   reference
     "RFC 5848: Signed Syslog Messages";
 }

 typedef syslog-severity {
   type enumeration {
     enum emergency {
       value 0;
       description
         "The severity level 'Emergency' indicates that the
          system is unusable.";
     }
     enum alert {
       value 1;
       description
         "The severity level 'Alert' indicates that an
          action must be taken immediately.";
     }
     enum critical {
       value 2;
       description
         "The severity level 'Critical' indicates a
          critical condition.";
     }
     enum error {
       value 3;
       description
         "The severity level 'Error' indicates an error
          condition.";
     }
     enum warning {
       value 4;
       description
         "The severity level 'Warning' indicates a warning
          condition.";
     }
     enum notice {
       value 5;
       description
         "The severity level 'Notice' indicates a normal
          but significant condition.";
     }
     enum info {
       value 6;
       description
         "The severity level 'Info' indicates an
          informational message.";
     }
     enum debug {
       value 7;
       description
         "The severity level 'Debug' indicates a
          debug-level message.";
     }
   }
   description
     "The definitions for Syslog message severity.
      Note that a lower value is a higher severity. Comparisons
      of equal-or-higher severity mean equal-or-lower numeric
      value";
   reference
     "RFC 5424: The Syslog Protocol";
 }

 identity syslog-facility {
   description
     "This identity is used as a base for all syslog
      facilities.";
   reference
     "RFC 5424: The Syslog Protocol";
 }

 identity kern {
   base syslog-facility;
   description
     "The facility for kernel messages (numerical code 0).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity user {
   base syslog-facility;
   description
     "The facility for user-level messages (numerical code 1).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity mail {
   base syslog-facility;
   description
     "The facility for the mail system (numerical code 2).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity daemon {
   base syslog-facility;
   description
     "The facility for the system daemons (numerical code 3).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity auth {
   base syslog-facility;
   description
     "The facility for security/authorization messages (numerical
      code 4).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity syslog {
   base syslog-facility;
   description
     "The facility for messages generated internally by a syslog
      daemon facility (numerical code 5).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity lpr {
   base syslog-facility;
   description
     "The facility for the line printer subsystem (numerical code
      6).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity news {
   base syslog-facility;
   description
     "The facility for the network news subsystem (numerical code
      7).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity uucp {
   base syslog-facility;
   description
     "The facility for the Unix-to-Unix Copy (UUCP) subsystem
      (numerical code 8).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity cron {
   base syslog-facility;
   description
     "The facility for the clock daemon (numerical code 9).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity authpriv {
   base syslog-facility;
   description
     "The facility for privileged security/authorization messages
      (numerical code 10).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity ftp {
   base syslog-facility;
   description
     "The facility for the FTP daemon (numerical code 11).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity ntp {
   base syslog-facility;
   description
     "The facility for the NTP subsystem (numerical code 12).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity audit {
   base syslog-facility;
   description
     "The facility for log audit messages (numerical code 13).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity console {
   base syslog-facility;
   description
     "The facility for log alert messages (numerical code 14).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity cron2 {
   base syslog-facility;
   description
     "The facility for the second clock daemon (numerical code
      15).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity local0 {
   base syslog-facility;
   description
     "The facility for local use 0 messages (numerical code 16).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity local1 {
   base syslog-facility;
   description
     "The facility for local use 1 messages (numerical code 17).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity local2 {
   base syslog-facility;
   description
     "The facility for local use 2 messages (numerical code 18).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity local3 {
   base syslog-facility;
   description
     "The facility for local use 3 messages (numerical code 19).";
   reference
     "RFC 5424: The Syslog Protocol";
 }

 identity local4 {
   base syslog-facility;
   description
     "The facility for local use 4 messages (numerical code 20).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity local5 {
   base syslog-facility;
   description
     "The facility for local use 5 messages (numerical code 21).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity local6 {
   base syslog-facility;
   description
     "The facility for local use 6 messages (numerical code 22).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity local7 {
   base syslog-facility;
   description
     "The facility for local use 7 messages (numerical code 23).";
   reference
     "RFC 5424: The Syslog Protocol, Section 6.2.1.";
 }

 identity action {
   description
     "Base identity for action for how a message will be
      handled.";
 }

 identity log {
   base action;
   description
     "This identity specifies that if the compare operation is
      true, the message will be logged.";
 }

 identity block {
   base action;
   description
     "This identity specifies that if the compare operation is
      true, the message will not be logged.";
 }

 identity stop {
   base action;
   description
     "This identity specifies that if the compare operation is
      true, the message will not be logged and no further
      processing will occur for it.";
 }

 grouping severity-filter {
   description
     "This grouping defines the processing used to select
      log messages by comparing syslog message severity using
      the following processing rules:
      - if 'none', do not match.
      - if 'all', match.
      - else, compare message severity with the specified
        severity according to the default compare rule (all
        messages of the specified severity and greater match)
        or if the select-adv-compare feature is present, use
        the advance-compare rule.";
   leaf severity {
     type union {
       type syslog-severity;
       type enumeration {
         enum none {
           value 2147483647;
           description
             "This enum describes the case where no
              severities are selected.";
         }
         enum all {
           value -2147483648;
           description
             "This enum describes the case where all
              severities are selected.";
         }
       }
     }
     mandatory true;
     description
       "This leaf specifies the syslog message severity.";
   }
   container advanced-compare {
     when "../severity != \"all\" and
           ../severity != \"none\"" {
       description
         "The advanced compare container is not applicable
          for severity 'all' or severity 'none'";
     }
     if-feature "select-adv-compare";
     leaf compare {
       type enumeration {
         enum equals {
           description
             "This enum specifies that the severity
              comparison operation will be equals.";
         }
         enum equals-or-higher {
           description
             "This enum specifies that the severity
              comparison operation will be equals or
              higher.";
         }
       }
       default "equals-or-higher";
       description
         "The compare operation can be used to specify the comparison
          operator that should be used to compare the syslog
          message severity with the specified severity.";
     }
     leaf action {
       type identityref {
         base action;
       }
       default "log";
       description
         "The action can be used to specify how the message
          should be handled. This may include logging the
          message, not logging the message (i.e., blocking
          it), or stopping further processing.";
     }
     description
       "This container describes additional severity compare
        operations that can be used in place of the default
        severity comparison.  The compare leaf specifies the
        type of compare operation that is done and the
        action leaf specifies the intended result.
        Example: compare-&gt;equals and action-&gt;block means
        messages that have a severity that are equal to the
        specified severity will not be logged.";
   }
 }

 grouping selector {
   description
     "This grouping defines a syslog selector, which is used to
      select log messages for the log-actions (console, file,
      remote, etc.).  Choose one or both of the following:
         facility [&lt;facility&gt; &lt;severity&gt;...]
         pattern-match regular-expression-match-string
      If both facility and pattern-match are specified, both
      must match in order for a log message to be selected.";
   container filter {
     description
       "This container describes the syslog filter
        parameters.";
     list facility-list {
       key "facility severity";
       ordered-by user;
       description
         "This list describes a collection of syslog
          facilities and severities.";
       leaf facility {
         type union {
           type identityref {
             base syslog-facility;
           }
           type enumeration {
             enum all {
               description
                 "This enum describes the case where
                  all facilities are requested.";
             }
           }
         }
         description
           "The leaf uniquely identifies a syslog
            facility.";
       }
       uses severity-filter;
     }
   }
   leaf pattern-match {
     if-feature "select-match";
     type string;
     description
       "This leaf describes a Posix 1003.2 regular expression
        string that can be used to select a syslog message for
        logging.  The match is performed on the SYSLOG-MSG
        field.";
     reference
       "RFC 5424: The Syslog Protocol
        Std-1003.1-2024 Regular Expressions";
   }
 }

 grouping structured-data {
   description
     "This grouping defines the syslog structured data option,
      which is used to select the format used to write log
      messages.";
   leaf structured-data {
     if-feature "structured-data";
     type boolean;
     default "false";
     description
       "This leaf describes how log messages are written.
        If true, messages will be written with one or more
        STRUCTURED-DATA elements; if false, messages will be
        written with STRUCTURED-DATA = NILVALUE.";
     reference
       "RFC 5424: The Syslog Protocol";
   }
 }

 container syslog {
   presence "Enables logging.";
   description
     "This container describes the configuration parameters for
      syslog.";
   container actions {
     description
       "This container describes the log-action parameters
        for syslog.";
     container console {
       if-feature "console-action";
       presence "Enables logging to the console";
       description
         "This container describes the configuration
          parameters for console logging.";
       uses selector;
     }
     container file {
       if-feature "file-action";
       description
         "This container describes the configuration
          parameters for file logging.  If file-archive
          limits are not supplied, it is assumed that
          the local implementation defined limits will
          be used.";
       list log-file {
         key "name";
         description
           "This list describes a collection of local
            logging files.";
         leaf name {
           type inet:uri {
             pattern 'file:.*';
           }
           description
             "This leaf specifies the name of the log
              file, which MUST use the uri scheme
              file:.";
           reference
             "RFC 8089: The file URI Scheme";
         }
         uses selector;
         uses structured-data;
         container file-rotation {
           description
             "This container describes the configuration
              parameters for log file rotation.";
           leaf number-of-files {
             if-feature "file-limit-size";
             type uint32;
             default "1";
             description
               "This leaf specifies the maximum number
                of log files retained.  Specify 1 for
                implementations that only support one
                log file.";
           }
           leaf max-file-size {
             if-feature "file-limit-size";
             type uint32;
             units "megabytes";
             description
               "This leaf specifies the maximum log
                file size.";
           }
           leaf rollover {
             if-feature "file-limit-duration";
             type uint32;
             units "minutes";
             description
               "This leaf specifies the length of time
                that log events should be written to a
                specific log file.  Log events that
                arrive after the rollover period cause
                the current log file to be closed and
                a new log file to be opened.";
           }
           leaf retention {
             if-feature "file-limit-duration";
             type uint32;
             units "minutes";
             description
               "This leaf specifies the length of time
                that completed/closed log event files
                should be stored in the file system
                before they are removed.";
           }
         }
       }
     }
     container remote {
       if-feature "remote-action";
       description
         "This container describes the configuration
          parameters for forwarding syslog messages
          to remote relays or collectors.";
       list destination {
         key "name";
         description
           "This list describes a collection of remote logging
            destinations.";
         leaf name {
           type string;
           description
             "An arbitrary name for the endpoint to connect to.";
         }
         choice transport {
           mandatory true;
           description
             "This choice describes the transport option.";
           case udp {
             container udp {
               description
                 "This container describes the UDP transport
                  options.";
               reference
                 "RFC 5426: Transmission of Syslog Messages over
                            UDP";
               list udp {
                 key "address";
                 description
                   "List of all UDP sessions.";
                 leaf address {
                   type inet:host;
                   description
                     "The leaf uniquely specifies the address of the
                      remote host. One of the following must be
                      specified:
                      - an ipv4 address,
                      - an ipv6 address, or a
                      - host name.";
                 }
                 leaf port {
                   type inet:port-number;
                   default "514";
                   description
                     "This leaf specifies the port number used to
                      deliver messages to the remote server.";
                 }
               }
             }
           }
           case tls {
             container tls {
               description
                 "This container describes the TLS transport
                  options.";
               reference
                 "RFC 5425: Transport Layer Security (TLS) Transport
                            Mapping for Syslog ";
               list tls {
                 key "address";
                 description
                   "List of all TLS-based sessions.";
                 leaf address {
                   type inet:host;
                   description
                     "The leaf uniquely specifies the address of the
                      remote host.  One of the following must be
                      specified: an ipv4 address, an ipv6 address,
                      or a host name.";
                 }
                 leaf port {
                   type inet:port-number;
                   default "6514";
                   description
                     "TCP port 6514 has been allocated as the
                      default port for syslog over TLS.";
                 }
                 uses tlsc:tls-client-grouping;
               }
             }
           }
         }
         uses selector;
         uses structured-data;
         leaf facility-override {
           type identityref {
             base syslog-facility;
           }
           description
             "If specified, this leaf specifies the facility used
              to override the facility in messages delivered to the
              remote server.";
         }
         leaf source-interface {
           if-feature "remote-source-interface";
           type if:interface-ref;
           description
             "This leaf sets the source interface to be used to
              send messages to the remote syslog server. If not set,
              messages can be sent on any interface.";
         }
         container signing {
           if-feature "signed-messages";
           presence "If present, syslog-signing options is
                     activated.";
           description
             "This container describes the configuration
              parameters for signed syslog messages.";
           reference
             "RFC 5848: Signed Syslog Messages";
           container cert-signers {
             description
               "This container describes the signing certificate
                configuration for Signature Group 0, which covers
                the case for administrators who want all Signature
                Blocks to be sent to a single destination.";
             list cert-signer {
               key "name";
               description
                 "This list describes a collection of syslog message
                  signers.";
               leaf name {
                 type string;
                 description
                   "This leaf specifies the name of the syslog
                    message signer.";
               }
               container cert {
                 uses ct:asymmetric-key-pair-with-cert-grouping;
                 description
                   "This is the certificate that is periodically
                    sent to the remote receiver.  The certificate is
                    inherently associated with its private
                    and public keys.";
               }
               leaf hash-algorithm {
                 type enumeration {
                   enum SHA1 {
                     value 1;
                     description
                       "This enum describes the SHA1 algorithm.";
                   }
                   enum SHA256 {
                     value 2;
                     description
                       "This enum describes the SHA256 algorithm.";
                   }
                 }
                 description
                   "This leaf describes the syslog signer hash
                    algorithm used.";
               }
             }
             leaf cert-initial-repeat {
               type uint32;
               default "3";
               description
                 "This leaf specifies the number of times each
                  Certificate Block should be sent before the first
                  message is sent.";
             }
             leaf cert-resend-delay {
               type uint32;
               units "seconds";
               default "3600";
               description
                 "This leaf specifies the maximum time delay in
                  seconds until resending the Certificate Block.";
             }
             leaf cert-resend-count {
               type uint32;
               default "0";
               description
                 "This leaf specifies the maximum number of other
                  syslog messages to send until resending the
                  Certificate Block.";
             }
             leaf sig-max-delay {
               type uint32;
               units "seconds";
               default "60";
               description
                 "This leaf specifies when to generate a new
                  Signature Block. If this many seconds have elapsed
                  since the message with the first message number
                  of the Signature Block was sent, a new Signature
                  Block should be generated.";
             }
             leaf sig-number-resends {
               type uint32;
               default "0";
               description
                 "This leaf specifies the number of times a
                  Signature Block is resent.  (It is recommended to
                  select a value of greater than 0 in particular
                  when the UDP transport as in RFC 5426 is used.)";
             }
             leaf sig-resend-delay {
               type uint32;
               units "seconds";
               default "5";
               description
                 "This leaf specifies when to send the next
                  Signature Block transmission based on time.  If
                  this many seconds have elapsed since the previous
                  sending of this Signature Block, resend it.";
             }
             leaf sig-resend-count {
               type uint32;
               default "0";
               description
                 "This leaf specifies when to send the next
                  Signature Block transmission based on a count.
                  If this many other syslog messages have been sent
                  since the previous sending of this Signature
                  Block, resend it. A value of 0 means that you
                  don't resend based on the number of messages.";
             }
           }
         }
       }
     }
   }
 }
}
</sourcecode>
        </figure>
      </section>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-6">
      <name slugifiedName="name-usage-examples">Usage Examples</name>
      <t indent="0" pn="section-6-1">The following examples are in XML <xref target="W3C.REC-xml-20081126" format="default" sectionFormat="of" derivedContent="W3C.REC-xml-20081126"/>.</t>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-6.1">
        <name slugifiedName="name-syslog-configuration-for-se">Syslog Configuration for Severity Critical</name>
        <t indent="0" pn="section-6.1-1">This example shows how the console logging of syslog of severity critical can be enabled.</t>
        <figure align="left" suppress-title="false" pn="figure-4">
          <name slugifiedName="name-syslog-configuration-for-sev">Syslog Configuration for Severity Critical</name>
          <sourcecode type="xml" markers="false" pn="section-6.1-2.1">
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;syslog xmlns="urn:ietf:params:xml:ns:yang:ietf-syslog"&gt;
 &lt;actions&gt;
   &lt;console&gt;
     &lt;filter&gt;
       &lt;facility-list&gt;
         &lt;facility&gt;all&lt;/facility&gt;
         &lt;severity&gt;critical&lt;/severity&gt;
       &lt;/facility-list&gt;
     &lt;/filter&gt;
   &lt;/console&gt;
 &lt;/actions&gt;
&lt;/syslog&gt;</sourcecode>
        </figure>
      </section>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-6.2">
        <name slugifiedName="name-remote-syslog-configuration">Remote Syslog Configuration</name>
        <t indent="0" pn="section-6.2-1">This example shows how the remote logging of syslogs to UDP destination
foo.example.com for facility auth and severity error can be enabled.</t>
        <figure align="left" suppress-title="false" pn="figure-5">
          <name slugifiedName="name-remote-syslog-configuration-2">Remote Syslog Configuration</name>
          <sourcecode type="xml" markers="false" pn="section-6.2-2.1">
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;syslog xmlns="urn:ietf:params:xml:ns:yang:ietf-syslog"&gt;
 &lt;actions&gt;
   &lt;remote&gt;
     &lt;destination&gt;
       &lt;name&gt;remote1&lt;/name&gt;
       &lt;udp&gt;
         &lt;udp&gt;
           &lt;address&gt;foo.example.com&lt;/address&gt;
         &lt;/udp&gt;
       &lt;/udp&gt;
       &lt;filter&gt;
         &lt;facility-list&gt;
           &lt;facility&gt;auth&lt;/facility&gt;
           &lt;severity&gt;error&lt;/severity&gt;
         &lt;/facility-list&gt;
       &lt;/filter&gt;
     &lt;/destination&gt;
   &lt;/remote&gt;
 &lt;/actions&gt;
&lt;/syslog&gt;</sourcecode>
        </figure>
      </section>
    </section>
    <section anchor="IANA" numbered="true" removeInRFC="false" toc="include" pn="section-7">
      <name slugifiedName="name-iana-considerations">IANA Considerations</name>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-7.1">
        <name slugifiedName="name-the-ietf-xml-registry">The IETF XML Registry</name>
        <t indent="0" pn="section-7.1-1">This document registers one URI in the "IETF XML Registry", following the format defined in <xref target="RFC3688" format="default" sectionFormat="of" derivedContent="RFC3688"/>:</t>
        <dl newline="false" spacing="compact" indent="3" pn="section-7.1-2">
          <dt pn="section-7.1-2.1">URI:</dt>
          <dd pn="section-7.1-2.2">urn:ietf:params:xml:ns:yang:ietf-syslog</dd>
          <dt pn="section-7.1-2.3">Registrant Contact:</dt>
          <dd pn="section-7.1-2.4">The IESG.</dd>
          <dt pn="section-7.1-2.5">XML:</dt>
          <dd pn="section-7.1-2.6">N/A; the requested URI is an XML namespace.</dd>
        </dl>
      </section>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-7.2">
        <name slugifiedName="name-the-yang-module-names-regis">The YANG Module Names Registry</name>
        <t indent="0" pn="section-7.2-1">This document registers one YANG module in the "YANG Module Names"
       registry <xref target="RFC8525" format="default" sectionFormat="of" derivedContent="RFC8525"/>, following the format in <xref target="RFC7950" format="default" sectionFormat="of" derivedContent="RFC7950"/>:</t>
        <dl spacing="compact" newline="false" indent="3" pn="section-7.2-2">
          <dt pn="section-7.2-2.1">Name:</dt>
          <dd pn="section-7.2-2.2">ietf-syslog</dd>
          <dt pn="section-7.2-2.3">Namespace:</dt>
          <dd pn="section-7.2-2.4">urn:ietf:params:xml:ns:yang:ietf-syslog</dd>
          <dt pn="section-7.2-2.5">Prefix:</dt>
          <dd pn="section-7.2-2.6">syslog</dd>
          <dt pn="section-7.2-2.7">Reference:</dt>
          <dd pn="section-7.2-2.8">RFC 9742</dd>
        </dl>
      </section>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-8">
      <name slugifiedName="name-security-considerations">Security Considerations</name>
      <t indent="0" pn="section-8-1">
 This section is modeled after the template defined in <xref target="I-D.ietf-netmod-rfc8407bis" format="default" sectionFormat="of" derivedContent="YANG-GUIDELINES"/>.
      </t>
      <t indent="0" pn="section-8-2">

   The "ietf-syslog" YANG module defines a data model that is designed to be
   accessed via YANG-based management protocols, such as NETCONF <xref target="RFC6241" format="default" sectionFormat="of" derivedContent="RFC6241"/> and RESTCONF <xref target="RFC8040" format="default" sectionFormat="of" derivedContent="RFC8040"/>. These protocols
   have to use a secure transport layer (e.g., SSH <xref target="RFC4252" format="default" sectionFormat="of" derivedContent="RFC4252"/>,
   TLS <xref target="RFC8446" format="default" sectionFormat="of" derivedContent="RFC8446"/>, and QUIC <xref target="RFC9000" format="default" sectionFormat="of" derivedContent="RFC9000"/>) and have
   to use mutual authentication.

      </t>
      <t indent="0" pn="section-8-3">

   The Network Configuration Access Control Model (NACM) <xref target="RFC8341" format="default" sectionFormat="of" derivedContent="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.
      </t>
      <t indent="0" pn="section-8-4">
   This module imports groupings from ietf-crypto-types YANG module
   defined in <xref target="RFC9640" format="default" sectionFormat="of" derivedContent="RFC9640">YANG
   Groupings for Crypto Types</xref>. Security considerations
   described in that document apply to this module also.
      </t>
      <t indent="0" pn="section-8-5">

   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 reasonably 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:

      </t>
      <dl newline="false" spacing="normal" indent="3" pn="section-8-6">
        <dt pn="section-8-6.1"> facility-filter/pattern-match:</dt>
        <dd pn="section-8-6.2">When writing
       this node, implementations <bcp14>MUST</bcp14> ensure that the regular
       expression pattern match is not constructed to cause a regular
       expression denial-of-service attack due to a pattern that
       causes the regular expression implementation to work very
       slowly (exponentially related to input size).
       </dd>
        <dt pn="section-8-6.3"> remote/destination/signing/cert-signer:</dt>
        <dd pn="section-8-6.4">When writing this subtree, implementations <bcp14>MUST NOT</bcp14>
       specify a private key that is used for any other purpose.</dd>
      </dl>
      <t indent="0" pn="section-8-7">

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments. It is thus important
   to control read access (e.g., via get, get-config, or notification) to
   these data nodes. Specifically, the following subtrees and data nodes have
   particular sensitivities/ vulnerabilities:

      </t>
      <dl newline="false" spacing="normal" indent="3" pn="section-8-8">
        <dt pn="section-8-8.1"> remote/destination/transport:</dt>
        <dd pn="section-8-8.2">This subtree
     contains information about other hosts in the network, the
     services available on those hosts, and the TLS transport
     certificate properties if TLS is selected as the transport
     protocol. Knowing that a service like syslog (udp/514) is
     enabled on the host will allow a malicious user to spam the
     host on that port.
     </dd>
        <dt pn="section-8-8.3"> remote/destination/signing:</dt>
        <dd pn="section-8-8.4">This subtree contains
     information about the syslog message signing properties,
     including signing certificate information.
     </dd>
      </dl>
      <t indent="0" pn="section-8-9">
   There are no particularly sensitive RPC or action operations.
      </t>
    </section>
  </middle>
  <back>
    <displayreference target="I-D.ietf-netmod-rfc8407bis" to="YANG-GUIDELINES"/>
    <references pn="section-9">
      <name slugifiedName="name-references">References</name>
      <references pn="section-9.1">
        <name slugifiedName="name-normative-references">Normative References</name>
        <reference anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119" quoteTitle="true" derivedAnchor="RFC2119">
          <front>
            <title>Key words for use in RFCs to Indicate Requirement Levels</title>
            <author fullname="S. Bradner" initials="S." surname="Bradner"/>
            <date month="March" year="1997"/>
            <abstract>
              <t indent="0">In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="2119"/>
          <seriesInfo name="DOI" value="10.17487/RFC2119"/>
        </reference>
        <reference anchor="RFC3688" target="https://www.rfc-editor.org/info/rfc3688" quoteTitle="true" derivedAnchor="RFC3688">
          <front>
            <title>The IETF XML Registry</title>
            <author fullname="M. Mealling" initials="M." surname="Mealling"/>
            <date month="January" year="2004"/>
            <abstract>
              <t indent="0">This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="81"/>
          <seriesInfo name="RFC" value="3688"/>
          <seriesInfo name="DOI" value="10.17487/RFC3688"/>
        </reference>
        <reference anchor="RFC5424" target="https://www.rfc-editor.org/info/rfc5424" quoteTitle="true" derivedAnchor="RFC5424">
          <front>
            <title>The Syslog Protocol</title>
            <author fullname="R. Gerhards" initials="R." surname="Gerhards"/>
            <date month="March" year="2009"/>
            <abstract>
              <t indent="0">This document describes the syslog protocol, which is used to convey event notification messages. This protocol utilizes a layered architecture, which allows the use of any number of transport protocols for transmission of syslog messages. It also provides a message format that allows vendor-specific extensions to be provided in a structured way.</t>
              <t indent="0">This document has been written with the original design goals for traditional syslog in mind. The need for a new layered specification has arisen because standardization efforts for reliable and secure syslog extensions suffer from the lack of a Standards-Track and transport-independent RFC. Without this document, each other standard needs to define its own syslog packet format and transport mechanism, which over time will introduce subtle compatibility issues. This document tries to provide a foundation that syslog extensions can build on. This layered architecture approach also provides a solid basis that allows code to be written once for each syslog feature rather than once for each transport. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5424"/>
          <seriesInfo name="DOI" value="10.17487/RFC5424"/>
        </reference>
        <reference anchor="RFC5425" target="https://www.rfc-editor.org/info/rfc5425" quoteTitle="true" derivedAnchor="RFC5425">
          <front>
            <title>Transport Layer Security (TLS) Transport Mapping for Syslog</title>
            <author fullname="F. Miao" initials="F." role="editor" surname="Miao"/>
            <author fullname="Y. Ma" initials="Y." role="editor" surname="Ma"/>
            <author fullname="J. Salowey" initials="J." role="editor" surname="Salowey"/>
            <date month="March" year="2009"/>
            <abstract>
              <t indent="0">This document describes the use of Transport Layer Security (TLS) to provide a secure connection for the transport of syslog messages. This document describes the security threats to syslog and how TLS can be used to counter such threats.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5425"/>
          <seriesInfo name="DOI" value="10.17487/RFC5425"/>
        </reference>
        <reference anchor="RFC5426" target="https://www.rfc-editor.org/info/rfc5426" quoteTitle="true" derivedAnchor="RFC5426">
          <front>
            <title>Transmission of Syslog Messages over UDP</title>
            <author fullname="A. Okmianski" initials="A." surname="Okmianski"/>
            <date month="March" year="2009"/>
            <abstract>
              <t indent="0">This document describes the transport for syslog messages over UDP/ IPv4 or UDP/IPv6. The syslog protocol layered architecture provides for support of any number of transport mappings. However, for interoperability purposes, syslog protocol implementers are required to support this transport mapping. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5426"/>
          <seriesInfo name="DOI" value="10.17487/RFC5426"/>
        </reference>
        <reference anchor="RFC5848" target="https://www.rfc-editor.org/info/rfc5848" quoteTitle="true" derivedAnchor="RFC5848">
          <front>
            <title>Signed Syslog Messages</title>
            <author fullname="J. Kelsey" initials="J." surname="Kelsey"/>
            <author fullname="J. Callas" initials="J." surname="Callas"/>
            <author fullname="A. Clemm" initials="A." surname="Clemm"/>
            <date month="May" year="2010"/>
            <abstract>
              <t indent="0">This document describes a mechanism to add origin authentication, message integrity, replay resistance, message sequencing, and detection of missing messages to the transmitted syslog messages. This specification is intended to be used in conjunction with the work defined in RFC 5424, "The Syslog Protocol". [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5848"/>
          <seriesInfo name="DOI" value="10.17487/RFC5848"/>
        </reference>
        <reference anchor="RFC6991" target="https://www.rfc-editor.org/info/rfc6991" quoteTitle="true" derivedAnchor="RFC6991">
          <front>
            <title>Common YANG Data Types</title>
            <author fullname="J. Schoenwaelder" initials="J." role="editor" surname="Schoenwaelder"/>
            <date month="July" year="2013"/>
            <abstract>
              <t indent="0">This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6991"/>
          <seriesInfo name="DOI" value="10.17487/RFC6991"/>
        </reference>
        <reference anchor="RFC7950" target="https://www.rfc-editor.org/info/rfc7950" quoteTitle="true" derivedAnchor="RFC7950">
          <front>
            <title>The YANG 1.1 Data Modeling Language</title>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <date month="August" year="2016"/>
            <abstract>
              <t indent="0">YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7950"/>
          <seriesInfo name="DOI" value="10.17487/RFC7950"/>
        </reference>
        <reference anchor="RFC8089" target="https://www.rfc-editor.org/info/rfc8089" quoteTitle="true" derivedAnchor="RFC8089">
          <front>
            <title>The "file" URI Scheme</title>
            <author fullname="M. Kerwin" initials="M." surname="Kerwin"/>
            <date month="February" year="2017"/>
            <abstract>
              <t indent="0">This document provides a more complete specification of the "file" Uniform Resource Identifier (URI) scheme and replaces the very brief definition in Section 3.10 of RFC 1738.</t>
              <t indent="0">It defines a common syntax that is intended to interoperate across the broad spectrum of existing usages. At the same time, it notes some other current practices around the use of file URIs.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8089"/>
          <seriesInfo name="DOI" value="10.17487/RFC8089"/>
        </reference>
        <reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174" quoteTitle="true" derivedAnchor="RFC8174">
          <front>
            <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title>
            <author fullname="B. Leiba" initials="B." surname="Leiba"/>
            <date month="May" year="2017"/>
            <abstract>
              <t indent="0">RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="8174"/>
          <seriesInfo name="DOI" value="10.17487/RFC8174"/>
        </reference>
        <reference anchor="RFC8341" target="https://www.rfc-editor.org/info/rfc8341" quoteTitle="true" derivedAnchor="RFC8341">
          <front>
            <title>Network Configuration Access Control Model</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <date month="March" year="2018"/>
            <abstract>
              <t indent="0">The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model.</t>
              <t indent="0">This document obsoletes RFC 6536.</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="91"/>
          <seriesInfo name="RFC" value="8341"/>
          <seriesInfo name="DOI" value="10.17487/RFC8341"/>
        </reference>
        <reference anchor="RFC8343" target="https://www.rfc-editor.org/info/rfc8343" quoteTitle="true" derivedAnchor="RFC8343">
          <front>
            <title>A YANG Data Model for Interface Management</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <date month="March" year="2018"/>
            <abstract>
              <t indent="0">This document defines a YANG data model for the management of network interfaces. It is expected that interface-type-specific data models augment the generic interfaces data model defined in this document. The data model includes definitions for configuration and system state (status information and counters for the collection of statistics).</t>
              <t indent="0">The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA) defined in RFC 8342.</t>
              <t indent="0">This document obsoletes RFC 7223.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8343"/>
          <seriesInfo name="DOI" value="10.17487/RFC8343"/>
        </reference>
        <reference anchor="RFC8525" target="https://www.rfc-editor.org/info/rfc8525" quoteTitle="true" derivedAnchor="RFC8525">
          <front>
            <title>YANG Library</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." surname="Schoenwaelder"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <author fullname="R. Wilton" initials="R." surname="Wilton"/>
            <date month="March" year="2019"/>
            <abstract>
              <t indent="0">This document describes a YANG library that provides information about the YANG modules, datastores, and datastore schemas used by a network management server. Simple caching mechanisms are provided to allow clients to minimize retrieval of this information. This version of the YANG library supports the Network Management Datastore Architecture (NMDA) by listing all datastores supported by a network management server and the schema that is used by each of these datastores.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8525"/>
          <seriesInfo name="DOI" value="10.17487/RFC8525"/>
        </reference>
        <reference anchor="RFC9640" target="https://www.rfc-editor.org/info/rfc9640" quoteTitle="true" derivedAnchor="RFC9640">
          <front>
            <title>YANG Data Types and Groupings for Cryptography</title>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <date month="October" year="2024"/>
            <abstract>
              <t indent="0">This document presents a YANG 1.1 (RFC 7950) module defining identities, typedefs, and groupings useful to cryptographic applications.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9640"/>
          <seriesInfo name="DOI" value="10.17487/RFC9640"/>
        </reference>
        <reference anchor="RFC9645" target="https://www.rfc-editor.org/info/rfc9645" quoteTitle="true" derivedAnchor="RFC9645">
          <front>
            <title>YANG Groupings for TLS Clients and TLS Servers</title>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <date month="October" year="2024"/>
            <abstract>
              <t indent="0">This document presents four YANG 1.1 modules -- three IETF modules and one supporting IANA module.</t>
              <t indent="0">The three IETF modules are "ietf-tls-common", "ietf-tls-client", and "ietf-tls-server". The "ietf-tls-client" and "ietf-tls-server" modules are the primary productions of this work, supporting the configuration and monitoring of TLS clients and servers.</t>
              <t indent="0">The IANA module is "iana-tls-cipher-suite-algs". This module defines YANG enumerations that provide support for an IANA-maintained algorithm registry.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9645"/>
          <seriesInfo name="DOI" value="10.17487/RFC9645"/>
        </reference>
        <reference anchor="Std-1003.1-2024" target="https://pubs.opengroup.org/onlinepubs/9799919799" quoteTitle="true" derivedAnchor="Std-1003.1-2024">
          <front>
            <title>"Chapter 9: Regular Expressions" The Open Group Base Specifications Issue 8, IEEE Std 1003.1-2024</title>
            <author>
              <organization showOnFrontPage="true">The Open Group</organization>
            </author>
            <date year="2024"/>
          </front>
        </reference>
        <reference anchor="W3C.REC-xml-20081126" target="https://www.w3.org/TR/2008/REC-xml-20081126/" quoteTitle="true" derivedAnchor="W3C.REC-xml-20081126">
          <front>
            <title>Extensible Markup Language (XML) 1.0 (Fifth Edition)</title>
            <author initials="T." surname="Bray" fullname="Tim Bray"/>
            <author initials="J." surname="Paoli" fullname="Jean Paoli"/>
            <author initials="C.M." surname="Sperberg-McQueen" fullname="C. M. Sperberg-McQueen"/>
            <author initials="E." surname="Maler" fullname="Eve Maler"/>
            <author initials="F." surname="Yergeau" fullname="François Yergeau"/>
            <date month="November" year="2008"/>
          </front>
          <seriesInfo name="World Wide Web Consortium Recommendation" value="REC-xml-20081126"/>
        </reference>
      </references>
      <references pn="section-9.2">
        <name slugifiedName="name-informative-references">Informative References</name>
        <reference anchor="RFC4252" target="https://www.rfc-editor.org/info/rfc4252" quoteTitle="true" derivedAnchor="RFC4252">
          <front>
            <title>The Secure Shell (SSH) Authentication Protocol</title>
            <author fullname="T. Ylonen" initials="T." surname="Ylonen"/>
            <author fullname="C. Lonvick" initials="C." role="editor" surname="Lonvick"/>
            <date month="January" year="2006"/>
            <abstract>
              <t indent="0">The Secure Shell Protocol (SSH) is a protocol for secure remote login and other secure network services over an insecure network. This document describes the SSH authentication protocol framework and public key, password, and host-based client authentication methods. Additional authentication methods are described in separate documents. The SSH authentication protocol runs on top of the SSH transport layer protocol and provides a single authenticated tunnel for the SSH connection protocol. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4252"/>
          <seriesInfo name="DOI" value="10.17487/RFC4252"/>
        </reference>
        <reference anchor="RFC6241" target="https://www.rfc-editor.org/info/rfc6241" quoteTitle="true" derivedAnchor="RFC6241">
          <front>
            <title>Network Configuration Protocol (NETCONF)</title>
            <author fullname="R. Enns" initials="R." role="editor" surname="Enns"/>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." role="editor" surname="Schoenwaelder"/>
            <author fullname="A. Bierman" initials="A." role="editor" surname="Bierman"/>
            <date month="June" year="2011"/>
            <abstract>
              <t indent="0">The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6241"/>
          <seriesInfo name="DOI" value="10.17487/RFC6241"/>
        </reference>
        <reference anchor="RFC8040" target="https://www.rfc-editor.org/info/rfc8040" quoteTitle="true" derivedAnchor="RFC8040">
          <front>
            <title>RESTCONF Protocol</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <date month="January" year="2017"/>
            <abstract>
              <t indent="0">This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8040"/>
          <seriesInfo name="DOI" value="10.17487/RFC8040"/>
        </reference>
        <reference anchor="RFC8340" target="https://www.rfc-editor.org/info/rfc8340" quoteTitle="true" derivedAnchor="RFC8340">
          <front>
            <title>YANG Tree Diagrams</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="L. Berger" initials="L." role="editor" surname="Berger"/>
            <date month="March" year="2018"/>
            <abstract>
              <t indent="0">This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="215"/>
          <seriesInfo name="RFC" value="8340"/>
          <seriesInfo name="DOI" value="10.17487/RFC8340"/>
        </reference>
        <reference anchor="RFC8342" target="https://www.rfc-editor.org/info/rfc8342" quoteTitle="true" derivedAnchor="RFC8342">
          <front>
            <title>Network Management Datastore Architecture (NMDA)</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." surname="Schoenwaelder"/>
            <author fullname="P. Shafer" initials="P." surname="Shafer"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <author fullname="R. Wilton" initials="R." surname="Wilton"/>
            <date month="March" year="2018"/>
            <abstract>
              <t indent="0">Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8342"/>
          <seriesInfo name="DOI" value="10.17487/RFC8342"/>
        </reference>
        <reference anchor="RFC8446" target="https://www.rfc-editor.org/info/rfc8446" quoteTitle="true" derivedAnchor="RFC8446">
          <front>
            <title>The Transport Layer Security (TLS) Protocol Version 1.3</title>
            <author fullname="E. Rescorla" initials="E." surname="Rescorla"/>
            <date month="August" year="2018"/>
            <abstract>
              <t indent="0">This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery.</t>
              <t indent="0">This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8446"/>
          <seriesInfo name="DOI" value="10.17487/RFC8446"/>
        </reference>
        <reference anchor="RFC9000" target="https://www.rfc-editor.org/info/rfc9000" quoteTitle="true" derivedAnchor="RFC9000">
          <front>
            <title>QUIC: A UDP-Based Multiplexed and Secure Transport</title>
            <author fullname="J. Iyengar" initials="J." role="editor" surname="Iyengar"/>
            <author fullname="M. Thomson" initials="M." role="editor" surname="Thomson"/>
            <date month="May" year="2021"/>
            <abstract>
              <t indent="0">This document defines the core of the QUIC transport protocol. QUIC provides applications with flow-controlled streams for structured communication, low-latency connection establishment, and network path migration. QUIC includes security measures that ensure confidentiality, integrity, and availability in a range of deployment circumstances. Accompanying documents describe the integration of TLS for key negotiation, loss detection, and an exemplary congestion control algorithm.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9000"/>
          <seriesInfo name="DOI" value="10.17487/RFC9000"/>
        </reference>
        <reference anchor="I-D.ietf-netmod-rfc8407bis" target="https://datatracker.ietf.org/doc/html/draft-ietf-netmod-rfc8407bis-24" quoteTitle="true" derivedAnchor="YANG-GUIDELINES">
          <front>
            <title>Guidelines for Authors and Reviewers of Documents Containing YANG Data Models</title>
            <author fullname="Andy Bierman" initials="A." surname="Bierman">
              <organization showOnFrontPage="true">YumaWorks</organization>
            </author>
            <author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
              <organization showOnFrontPage="true">Orange</organization>
            </author>
            <author fullname="Qin Wu" initials="Q." surname="Wu">
              <organization showOnFrontPage="true">Huawei</organization>
            </author>
            <date day="18" month="April" year="2025"/>
            <abstract>
              <t indent="0">This memo provides guidelines for authors and reviewers of specifications containing YANG modules, including IANA-maintained modules. Recommendations and procedures are defined, which are intended to increase interoperability and usability of Network Configuration Protocol (NETCONF) and RESTCONF Protocol implementations that utilize YANG modules. This document obsoletes RFC 8407. Also, this document updates RFC 8126 by providing additional guidelines for writing the IANA considerations for RFCs that specify IANA-maintained modules.</t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-netmod-rfc8407bis-24"/>
          <refcontent>Work in Progress</refcontent>
        </reference>
      </references>
    </references>
    <section anchor="tree-diagrams" numbered="true" removeInRFC="false" toc="include" pn="section-appendix.a">
      <name slugifiedName="name-tree-diagrams">Tree Diagrams</name>
      <section anchor="complete-tree-diagram" numbered="true" removeInRFC="false" toc="include" pn="section-appendix.a.1">
        <name slugifiedName="name-complete-tree-diagram">Complete Tree Diagram</name>
        <sourcecode type="yangtree" markers="false" pn="section-appendix.a.1-1">
[note: '\' line wrapping for formatting only]

module: ietf-syslog
  +--rw syslog!
     +--rw actions
        +--rw console! {console-action}?
        |  +--rw filter
        |  |  +--rw facility-list* [facility severity]
        |  |     +--rw facility            union
        |  |     +--rw severity            union
        |  |     +--rw advanced-compare {select-adv-compare}?
        |  |        +--rw compare?   enumeration
        |  |        +--rw action?    identityref
        |  +--rw pattern-match?   string {select-match}?
        +--rw file {file-action}?
        |  +--rw log-file* [name]
        |     +--rw name               inet:uri
        |     +--rw filter
        |     |  +--rw facility-list* [facility severity]
        |     |     +--rw facility            union
        |     |     +--rw severity            union
        |     |     +--rw advanced-compare {select-adv-compare}?
        |     |        +--rw compare?   enumeration
        |     |        +--rw action?    identityref
        |     +--rw pattern-match?     string {select-match}?
        |     +--rw structured-data?   boolean {structured-data}?
        |     +--rw file-rotation
        |        +--rw number-of-files?   uint32 {file-limit-size}?
        |        +--rw max-file-size?     uint32 {file-limit-size}?
        |        +--rw rollover?          uint32
        |        |       {file-limit-duration}?
        |        +--rw retention?         uint32
        |                {file-limit-duration}?
        +--rw remote {remote-action}?
           +--rw destination* [name]
              +--rw name                 string
              +--rw (transport)
              |  +--:(udp)
              |  |  +--rw udp
              |  |     +--rw udp* [address]
              |  |        +--rw address    inet:host
              |  |        +--rw port?      inet:port-number
              |  +--:(tls)
              |     +--rw tls
              |        +--rw tls* [address]
              |           +--rw address                  inet:host
              |           +--rw port?
              |           |       inet:port-number
              |           +--rw client-identity!
              |           |  +--rw (auth-type)
              |           |     +--:(certificate)
              |           |     |        {client-ident-x509-cert}?
              |           |     |  +--rw certificate
              |           |     |     +--rw (inline-or-keystore)
              |           |     |        +--:(inline)
              |           |     |        |        {inline-definition\
s-supported}?
              |           |     |        |  +--rw inline-definition
              |           |     |        |     +--rw public-key-form\
at?
              |           |     |        |     |       identityref
              |           |     |        |     +--rw public-key?
              |           |     |        |     |       binary
              |           |     |        |     +--rw private-key-for\
mat?
              |           |     |        |     |       identityref
              |           |     |        |     +--rw (private-key-ty\
pe)
              |           |     |        |     |  +--:(cleartext-pri\
vate-key)
              |           |     |        |     |  |        {cleartex\
t-private-keys}?
              |           |     |        |     |  |  +--rw cleartext\
-private-key?
              |           |     |        |     |  |          binary
              |           |     |        |     |  +--:(hidden-privat\
e-key)
              |           |     |        |     |  |        {hidden-p\
rivate-keys}?
              |           |     |        |     |  |  +--rw hidden-pr\
ivate-key?
              |           |     |        |     |  |          empty
              |           |     |        |     |  +--:(encrypted-pri\
vate-key)
              |           |     |        |     |           {encrypte\
d-private-keys}?
              |           |     |        |     |     +--rw encrypted\
-private-key
              |           |     |        |     |        +--rw encryp\
ted-by
              |           |     |        |     |        +--rw encryp\
ted-value-format
              |           |     |        |     |        |       iden\
tityref
              |           |     |        |     |        +--rw encryp\
ted-value
              |           |     |        |     |                bina\
ry
              |           |     |        |     +--rw cert-data?
              |           |     |        |     |       end-entity-ce\
rt-cms
              |           |     |        |     +---n certificate-exp\
iration
              |           |     |        |     |       {certificate-\
expiration-notification}?
              |           |     |        |     |  +-- expiration-dat\
e
              |           |     |        |     |          yang:date-\
and-time
              |           |     |        |     +---x generate-csr
              |           |     |        |             {csr-generati\
on}?
              |           |     |        |        +---w input
              |           |     |        |        |  +---w csr-forma\
t
              |           |     |        |        |  |       identit\
yref
              |           |     |        |        |  +---w csr-info
              |           |     |        |        |          csr-inf\
o
              |           |     |        |        +--ro output
              |           |     |        |           +--ro (csr-type\
)
              |           |     |        |              +--:(p10-csr\
)
              |           |     |        |                 +--ro p10\
-csr?
              |           |     |        |                         p\
10-csr
              |           |     |        +--:(central-keystore)
              |           |     |                 {central-keystore-\
supported,asymmetric-keys}?
              |           |     |           +--rw central-keystore-r\
eference
              |           |     |              +--rw asymmetric-key?\

              |           |     |              |       ks:central-as\
ymmetric-key-ref
              |           |     |              |       {central-keys\
tore-supported,asymmetric-keys}?
              |           |     |              +--rw certificate?
              |           |     |                      leafref
              |           |     +--:(raw-public-key)
              |           |     |        {client-ident-raw-public-ke\
y}?
              |           |     |  +--rw raw-private-key
              |           |     |     +--rw (inline-or-keystore)
              |           |     |        +--:(inline)
              |           |     |        |        {inline-definition\
s-supported}?
              |           |     |        |  +--rw inline-definition
              |           |     |        |     +--rw public-key-form\
at?
              |           |     |        |     |       identityref
              |           |     |        |     +--rw public-key?
              |           |     |        |     |       binary
              |           |     |        |     +--rw private-key-for\
mat?
              |           |     |        |     |       identityref
              |           |     |        |     +--rw (private-key-ty\
pe)
              |           |     |        |        +--:(cleartext-pri\
vate-key)
              |           |     |        |        |        {cleartex\
t-private-keys}?
              |           |     |        |        |  +--rw cleartext\
-private-key?
              |           |     |        |        |          binary
              |           |     |        |        +--:(hidden-privat\
e-key)
              |           |     |        |        |        {hidden-p\
rivate-keys}?
              |           |     |        |        |  +--rw hidden-pr\
ivate-key?
              |           |     |        |        |          empty
              |           |     |        |        +--:(encrypted-pri\
vate-key)
              |           |     |        |                 {encrypte\
d-private-keys}?
              |           |     |        |           +--rw encrypted\
-private-key
              |           |     |        |              +--rw encryp\
ted-by
              |           |     |        |              +--rw encryp\
ted-value-format
              |           |     |        |              |       iden\
tityref
              |           |     |        |              +--rw encryp\
ted-value
              |           |     |        |                      bina\
ry
              |           |     |        +--:(central-keystore)
              |           |     |                 {central-keystore-\
supported,asymmetric-keys}?
              |           |     |           +--rw central-keystore-r\
eference?
              |           |     |                   ks:central-asymm\
etric-key-ref
              |           |     +--:(tls12-psk)
              |           |     |        {client-ident-tls12-psk}?
              |           |     |  +--rw tls12-psk
              |           |     |     +--rw (inline-or-keystore)
              |           |     |     |  +--:(inline)
              |           |     |     |  |        {inline-definition\
s-supported}?
              |           |     |     |  |  +--rw inline-definition
              |           |     |     |  |     +--rw key-format?
              |           |     |     |  |     |       identityref
              |           |     |     |  |     +--rw (key-type)
              |           |     |     |  |        +--:(cleartext-sym\
metric-key)
              |           |     |     |  |        |  +--rw cleartext\
-symmetric-key?
              |           |     |     |  |        |          binary
              |           |     |     |  |        |          {cleart\
ext-symmetric-keys}?
              |           |     |     |  |        +--:(hidden-symmet\
ric-key)
              |           |     |     |  |        |        {hidden-s\
ymmetric-keys}?
              |           |     |     |  |        |  +--rw hidden-sy\
mmetric-key?
              |           |     |     |  |        |          empty
              |           |     |     |  |        +--:(encrypted-sym\
metric-key)
              |           |     |     |  |                 {encrypte\
d-symmetric-keys}?
              |           |     |     |  |           +--rw encrypted\
-symmetric-key
              |           |     |     |  |              +--rw encryp\
ted-by
              |           |     |     |  |              +--rw encryp\
ted-value-format
              |           |     |     |  |              |       iden\
tityref
              |           |     |     |  |              +--rw encryp\
ted-value
              |           |     |     |  |                      bina\
ry
              |           |     |     |  +--:(central-keystore)
              |           |     |     |           {central-keystore-\
supported,symmetric-keys}?
              |           |     |     |     +--rw central-keystore-r\
eference?
              |           |     |     |             ks:central-symme\
tric-key-ref
              |           |     |     +--rw id?
              |           |     |             string
              |           |     +--:(tls13-epsk)
              |           |              {client-ident-tls13-epsk}?
              |           |        +--rw tls13-epsk
              |           |           +--rw (inline-or-keystore)
              |           |           |  +--:(inline)
              |           |           |  |        {inline-definition\
s-supported}?
              |           |           |  |  +--rw inline-definition
              |           |           |  |     +--rw key-format?
              |           |           |  |     |       identityref
              |           |           |  |     +--rw (key-type)
              |           |           |  |        +--:(cleartext-sym\
metric-key)
              |           |           |  |        |  +--rw cleartext\
-symmetric-key?
              |           |           |  |        |          binary
              |           |           |  |        |          {cleart\
ext-symmetric-keys}?
              |           |           |  |        +--:(hidden-symmet\
ric-key)
              |           |           |  |        |        {hidden-s\
ymmetric-keys}?
              |           |           |  |        |  +--rw hidden-sy\
mmetric-key?
              |           |           |  |        |          empty
              |           |           |  |        +--:(encrypted-sym\
metric-key)
              |           |           |  |                 {encrypte\
d-symmetric-keys}?
              |           |           |  |           +--rw encrypted\
-symmetric-key
              |           |           |  |              +--rw encryp\
ted-by
              |           |           |  |              +--rw encryp\
ted-value-format
              |           |           |  |              |       iden\
tityref
              |           |           |  |              +--rw encryp\
ted-value
              |           |           |  |                      bina\
ry
              |           |           |  +--:(central-keystore)
              |           |           |           {central-keystore-\
supported,symmetric-keys}?
              |           |           |     +--rw central-keystore-r\
eference?
              |           |           |             ks:central-symme\
tric-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 ca-certs! {server-auth-x509-cert}\
?
              |           |  |  +--rw (inline-or-truststore)
              |           |  |     +--:(inline)
              |           |  |     |        {inline-definitions-supp\
orted}?
              |           |  |     |  +--rw inline-definition
              |           |  |     |     +--rw certificate* [name]
              |           |  |     |        +--rw name
              |           |  |     |        |       string
              |           |  |     |        +--rw cert-data
              |           |  |     |        |       trust-anchor-cer\
t-cms
              |           |  |     |        +---n certificate-expira\
tion
              |           |  |     |                {certificate-exp\
iration-notification}?
              |           |  |     |           +-- expiration-date
              |           |  |     |                   yang:date-and\
-time
              |           |  |     +--:(central-truststore)
              |           |  |              {central-truststore-supp\
orted,certificates}?
              |           |  |        +--rw central-truststore-refer\
ence?
              |           |  |                ts:central-certificate\
-bag-ref
              |           |  +--rw ee-certs! {server-auth-x509-cert}\
?
              |           |  |  +--rw (inline-or-truststore)
              |           |  |     +--:(inline)
              |           |  |     |        {inline-definitions-supp\
orted}?
              |           |  |     |  +--rw inline-definition
              |           |  |     |     +--rw certificate* [name]
              |           |  |     |        +--rw name
              |           |  |     |        |       string
              |           |  |     |        +--rw cert-data
              |           |  |     |        |       trust-anchor-cer\
t-cms
              |           |  |     |        +---n certificate-expira\
tion
              |           |  |     |                {certificate-exp\
iration-notification}?
              |           |  |     |           +-- expiration-date
              |           |  |     |                   yang:date-and\
-time
              |           |  |     +--:(central-truststore)
              |           |  |              {central-truststore-supp\
orted,certificates}?
              |           |  |        +--rw central-truststore-refer\
ence?
              |           |  |                ts:central-certificate\
-bag-ref
              |           |  +--rw raw-public-keys!
              |           |  |       {server-auth-raw-public-key}?
              |           |  |  +--rw (inline-or-truststore)
              |           |  |     +--:(inline)
              |           |  |     |        {inline-definitions-supp\
orted}?
              |           |  |     |  +--rw inline-definition
              |           |  |     |     +--rw public-key* [name]
              |           |  |     |        +--rw name
              |           |  |     |        |       string
              |           |  |     |        +--rw public-key-format
              |           |  |     |        |       identityref
              |           |  |     |        +--rw public-key
              |           |  |     |                binary
              |           |  |     +--:(central-truststore)
              |           |  |              {central-truststore-supp\
orted,public-keys}?
              |           |  |        +--rw central-truststore-refer\
ence?
              |           |  |                ts:central-public-key-\
bag-ref
              |           |  +--rw tls12-psks?        empty
              |           |  |       {server-auth-tls12-psk}?
              |           |  +--rw tls13-epsks?       empty
              |           |          {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-algo\
rithm
              |           +--rw keepalives {tls-client-keepalives}?
              |              +--rw peer-allowed-to-send?   empty
              |              +--rw test-peer-aliveness!
              |                 +--rw max-wait?       uint16
              |                 +--rw max-attempts?   uint8
              +--rw filter
              |  +--rw facility-list* [facility severity]
              |     +--rw facility            union
              |     +--rw severity            union
              |     +--rw advanced-compare {select-adv-compare}?
              |        +--rw compare?   enumeration
              |        +--rw action?    identityref
              +--rw pattern-match?       string {select-match}?
              +--rw structured-data?     boolean {structured-data}?
              +--rw facility-override?   identityref
              +--rw source-interface?    if:interface-ref
              |       {remote-source-interface}?
              +--rw signing! {signed-messages}?
                 +--rw cert-signers
                    +--rw cert-signer* [name]
                    |  +--rw name              string
                    |  +--rw cert
                    |  |  +--rw public-key-format?
                    |  |  |       identityref
                    |  |  +--rw public-key?                    binar\
y
                    |  |  +--rw private-key-format?
                    |  |  |       identityref
                    |  |  +--rw (private-key-type)
                    |  |  |  +--:(cleartext-private-key)
                    |  |  |  |        {cleartext-private-keys}?
                    |  |  |  |  +--rw cleartext-private-key?   binar\
y
                    |  |  |  +--:(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-notificati\
on}?
                    |  |  |  +-- 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
                    |  +--rw hash-algorithm?   enumeration
                    +--rw cert-initial-repeat?   uint32
                    +--rw cert-resend-delay?     uint32
                    +--rw cert-resend-count?     uint32
                    +--rw sig-max-delay?         uint32
                    +--rw sig-number-resends?    uint32
                    +--rw sig-resend-delay?      uint32
                    +--rw sig-resend-count?      uint32
</sourcecode>
      </section>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-appendix.b">
      <name slugifiedName="name-implementer-guidelines">Implementer Guidelines</name>
      <section anchor="extending_facilities" numbered="true" removeInRFC="false" toc="include" pn="section-appendix.b.1">
        <name slugifiedName="name-extending-facilities">Extending Facilities</name>
        <t indent="0" pn="section-appendix.b.1-1">Many vendors extend the list of facilities available for logging in
        their implementation. Additional facilities may not work with the
        syslog protocol as defined in <xref target="RFC5424" format="default" sectionFormat="of" derivedContent="RFC5424"/>. Thus, such facilities
        apply for local syslog-like logging functionality.</t>
        <t indent="0" pn="section-appendix.b.1-2">The following is an example that shows how additional facilities
        could be added to the list of available facilities (two facilities are added in this example):</t>
        <sourcecode type="yang" name="example-vendor-syslog-types@2025-04-30.yang" markers="false" pn="section-appendix.b.1-3">
module example-vendor-syslog-types {
  namespace "http://example.com/ns/vendor-syslog-types";
  prefix vendor-syslogtypes;

  import ietf-syslog {
    prefix syslog;
  }

  organization
    "Example, Inc.";
  contact
    "Example, Inc.
     Customer Service

     Email: syslog-yang@example.com";
  description
    "This module contains a collection of vendor-specific YANG type
     definitions for Syslog.";

  revision 2025-04-30 {
    description
      "Version 1.0";
    reference
      "Vendor Syslog Types: Syslog YANG Module";
  }

  identity vendor_specific_type_1 {
    base syslog:syslog-facility;
    description
      "Adding vendor-specific type 1 to syslog-facility";
  }

  identity vendor_specific_type_2 {
    base syslog:syslog-facility;
    description
      "Adding vendor-specific type 2 to syslog-facility";
  }
}</sourcecode>
      </section>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-appendix.b.2">
        <name slugifiedName="name-syslog-terminal-output">Syslog Terminal Output</name>
        <t indent="0" pn="section-appendix.b.2-1">Terminal output with requirements more complex than the console
  subtree currently provides are expected to be supported via vendor
  extensions rather than handled via the file subtree.</t>
      </section>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-appendix.b.3">
        <name slugifiedName="name-syslog-file-naming-conventi">Syslog File Naming Convention</name>
        <t indent="0" pn="section-appendix.b.3-1">The syslog/file/log-file/file-rotation container contains
  configuration parameters for syslog file rotation.  This section
  describes how these fields might be used by an implementer to name
  syslog files in a rotation process.  This information is offered as	
  an informative guide only.</t>
        <t indent="0" pn="section-appendix.b.3-2">When an active syslog file with a name specified by log-file/name
  reaches log-file/max-file-size and/or syslog events arrive after the
  period specified by log-file/rollover, the logging system can close	
  the file, compress it, and name the archive file &lt;log-file/
  name&gt;.0.gz.  The logging system can then open a new active syslog
  file &lt;log-file/name&gt;.</t>
        <t indent="0" pn="section-appendix.b.3-3">When the new syslog file reaches either of the size limits referenced	
  above, &lt;log-file/name&gt;.0.gz can be renamed &lt;log-file/name&gt;.1.gz and
  the new syslog file can be closed, compressed, and renamed &lt;log-file/
  name&gt;.0.gz.  Each time that a new syslog file is closed, each of the
  prior syslog archive files named &lt;log-file/name&gt;.&lt;n&gt;.gz can be
  renamed to &lt;log-file/name&gt;.&lt;n + 1&gt;.gz.</t>
        <t indent="0" pn="section-appendix.b.3-4">Removal of archive log files could occur when either or both:</t>
        <ul bare="false" empty="false" indent="3" spacing="normal" pn="section-appendix.b.3-5">
          <li pn="section-appendix.b.3-5.1">log-file/number-of-files is specified. The logging system can create
    up to log-file/number-of-files syslog archive files, after which the
    contents of the oldest archived file could be overwritten.</li>
          <li pn="section-appendix.b.3-5.2">log-file/retention is specified. The logging system can remove those	
    syslog archive files whose file expiration time (file creation time
    plus the specified log-file/retention time) is prior to the current
    time.</li>
        </ul>
      </section>
    </section>
    <section numbered="false" anchor="Acknowledgements" removeInRFC="false" toc="include" pn="section-appendix.c">
      <name slugifiedName="name-acknowledgements">Acknowledgements</name>
      <t indent="0" pn="section-appendix.c-1">The authors wish to thank the following who commented on this
      proposal:</t>
      <t indent="0" pn="section-appendix.c-2"><contact fullname="Andy Bierman"/>, <contact fullname="Martin       Bjorklund"/>, <contact fullname="Alex Campbell"/>, <contact fullname="Alex Clemm"/>, <contact fullname="Francis Dupont"/>, <contact fullname="Jim Gibson"/>, <contact fullname="Jeffrey Haas"/>, <contact fullname="Bob Harold"/>, <contact fullname="John Heasley"/>, <contact fullname="Giles Heron"/>, <contact fullname="Lisa Huang"/>, <contact fullname="Mahesh Jethanandani"/>, <contact fullname="Warren Kumari"/>,
      <contact fullname="Jeffrey K Lange"/>, <contact fullname="Jan       Lindblad"/>, <contact fullname="Chris Lonvick"/>, <contact fullname="Alexey Melnikov"/>, <contact fullname="Kathleen Moriarty"/>,
      <contact fullname="Tom Petch"/>, <contact fullname="Adam Roach"/>,
      <contact fullname="Juergen Schoenwaelder"/>, <contact fullname="Phil       Shafer"/>, <contact fullname="Yaron Sheffer"/>, <contact fullname="Jason       Sterne"/>, <contact fullname="Peter Van Horne"/>, <contact fullname="Kent Watsen"/>, <contact fullname="Bert Wijnen"/>, <contact fullname="Dale R Worley"/>, and <contact fullname="Aleksandr       Zhdankin"/>.</t>
    </section>
    <section anchor="authors-addresses" numbered="false" removeInRFC="false" toc="include" pn="section-appendix.d">
      <name slugifiedName="name-authors-addresses">Authors' Addresses</name>
      <author fullname="Joe Clarke" initials="J" role="editor" surname="Clarke">
        <organization showOnFrontPage="true">Cisco</organization>
        <address>
          <postal>
            <country>United States of America</country>
          </postal>
          <email>jclarke@cisco.com</email>
        </address>
      </author>
      <author fullname="Mahesh Jethanandani" initials="M" role="editor" surname="Jethanandani">
        <organization showOnFrontPage="true">Kloud Services</organization>
        <address>
          <postal>
            <country>United States of America</country>
          </postal>
          <email>mjethanandani@gmail.com</email>
        </address>
      </author>
      <author fullname="Clyde Wildes" initials="C" role="editor" surname="Wildes">
        <organization showOnFrontPage="true">Cisco Systems Inc.</organization>
        <address>
          <postal>
            <street>170 West Tasman Drive</street>
            <city>San Jose</city>
            <region>CA</region>
            <code>95134</code>
            <country>United States of America</country>
          </postal>
          <phone>+1 415 819-6111</phone>
          <email>clyde@clydewildes.com</email>
        </address>
      </author>
      <author fullname="Kiran Koushik" initials="K" role="editor" surname="Koushik">
        <organization showOnFrontPage="true">Verizon Wireless</organization>
        <address>
          <postal>
            <street>500 W Dove Rd.</street>
            <city>Southlake</city>
            <region>TX</region>
            <code>76092</code>
            <country>United States of America</country>
          </postal>
          <phone>+1 512 650-0210</phone>
          <email>kirankoushik.agraharasreenivasa@verizonwireless.com</email>
        </address>
      </author>
    </section>
  </back>
</rfc>
