<?xml version="1.0" encoding="US-ASCII"?>
<?rfc toc="yes"?>
<?rfc symrefs="yes"?>
<?rfc sortrefs="yes" ?>
<?rfc compact="yes"?>
<?rfc subcompact="no"?>
<?rfc linkmailto="no" ?>
<?rfc editing="no" ?>
<?rfc comments="yes" ?>
<?rfc inline="yes"?>
<?rfc rfcedstyle="yes"?>
<?rfc-ext allow-markup-in-artwork="yes" ?>
<?rfc-ext include-index="no" ?>
<!--<?rfc strict="no"?> --> version='1.0' encoding='UTF-8'?>

<!DOCTYPE rfc [
  <!ENTITY nbsp    "&#160;">
  <!ENTITY zwsp   "&#8203;">
  <!ENTITY nbhy   "&#8209;">
  <!ENTITY wj     "&#8288;">
]>

<rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="std" docName="draft-ietf-netmod-syslog-model-33" number="9742" obsoletes="" updates="" ipr="trust200902" submissionType="IETF"
    consensus="true">
    <?rfc toc="yes"?> consensus="true" tocInclude="true" symRefs="true" sortRefs="true" version="3" xml:lang="en">

  <front>
    <title abbrev="Syslog Management">A YANG Data Model for Syslog Configuration</title>
    <seriesInfo name="RFC" value="9742"/>
    <author fullname="Joe Clarke" initials="J" role="editor" surname="Clarke">
      <organization>Cisco</organization>
      <address>
        <postal>
          <country>US</country>
          <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>Kloud Services</organization>
      <address>
        <postal>
          <country>US</country>
          <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>Cisco Systems Inc.</organization>
      <address>
        <postal>
          <street>170 West Tasman Drive</street>
          <city>San Jose</city>
          <region>CA</region>
          <code>95134</code>
          <country>US</country>
          <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>Verizon Wireless</organization>
      <address>
        <postal>
          <street>500 W Dove Rd.</street>
          <city>Southlake</city>
          <region>TX</region>
          <code>76092</code>

          <country>US</country>
          <country>United States of America</country>
        </postal>
        <phone>+1 512 650-0210</phone>
        <email>kirankoushik.agraharasreenivasa@verizonwireless.com</email>
      </address>
    </author>

    <date/>

    <area>General</area>

    <workgroup>NETMOD WG</workgroup>
    <date month="March" year="2025"/>
    <area>OPS</area>
    <workgroup>netmod</workgroup>

<!-- [rfced] Please insert any keywords (beyond those that appear in
the title) for use on https://www.rfc-editor.org/search. -->

<keyword>example</keyword>
<!--[rfced] We have received guidance from Benoit Claise and the YANG
Doctors that "YANG module" and "YANG data model" are preferred.
We have updated the text to use these forms.  Please review.
-->

<!-- [rfced] Some author comments are present in the XML. Please confirm
that no updates related to these comments are outstanding. Note that the
comments will be deleted prior to publication.
-->

    <abstract>
      <t>
	This document defines a YANG data model for the configuration
 of a syslog process. It is intended that this data model be used by
	vendors who implement syslog collectors in their systems.
      </t>
    </abstract>
  </front>
  <middle>
    <section title="Introduction">
    <section>
      <name>Introduction</name>
      <t>This document defines a YANG <xref target="RFC7950"/>
 configuration
      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"/>
 to install, manipulate, and
      delete the configuration of network devices.</t>
      <t>The data model makes use of the YANG "feature" construct which that allows
      implementations to support only those syslog features that lie within
      their capabilities.</t>
      <t>
	This module can be used to configure the syslog application
	conceptual layers as implemented on the syslog collector.
      </t>
      <t>Essentially, a syslog process receives messages (from the kernel,
      processes, applications applications, or other syslog processes) and processes them.
      The processing may involve logging to a local file, and/or displaying on
      console, and/or relaying to syslog processes on other machines. The
      processing
      process is determined by the "facility" that originated the message
      and the "severity" assigned to the message by the facility.</t>
      <t>Such definitions of syslog protocol are defined in
      <xref target="RFC5424"/>
, and are used in this RFC.</t>
      <t>The YANG data model in this document conforms to the Network Management
      Datastore Architecture defined in
      [RFC8342].</t>

    <section title="Requirements Language">
      <t>The <xref target="RFC8342"/>.</t>
      <section>
        <name>Requirements Language</name>
        <t>
    The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
        "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", "<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
        "OPTIONAL" "<bcp14>OPTIONAL</bcp14>" in this document are
    to be interpreted as described in BCP
        14 BCP&nbsp;14 <xref target="RFC2119"/>
    <xref target="RFC8174"/> when, and only when, they appear in all capitals,
    as shown here.</t> here.
        </t>
      </section>
    </section>

<section title="Terminology">
    <section>
      <name>Terminology</name>
      <t>
    The following terms are used throughout this document:
      </t>
  <ul>
    <li>
      Originator: an
      <dl spacing="normal" newline="false">
      <dt>Originator:</dt><dd>An "originator" refers to an entity that generates
      syslog content to be carried in a message.  The term is defined
      in <xref target="RFC5424"/>
    </li>

    <li>
      Relay: A target="RFC5424"/>.</dd>

      <dt>Relay:</dt> <dd>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"/>
    </li>

    <li>
      Collector: A target="RFC5424"/>.</dd>

      <dt>Collector:</dt> <dd>A "collector" gathers syslog content for
      further analysis. The term is defined in <xref
      target="RFC5424"/>.
    </li>

    <li>
      Action: The target="RFC5424"/>.</dd>

      <dt>Action:</dt> <dd>The term "action" refers to the processing process that takes
      place for each syslog message received.
    </li>
  </ul> received.</dd>
      </dl>
    </section>

<section title="NMDA Compliance">
    <section>
      <name>NMDA Compliance</name>
      <t>The YANG data model in this document conforms to the Network Management
  Datastore Architecture (NMDA) defined in
    <xref target="RFC8342"/>
.
  </t>
</section>

<section title="Editorial Note (To be removed by RFC Editor)">
  <t>This document contains many placeholder values that need to be
        replaced with finalized values at the time of publication. This note
        summarizes all of the substitutions that are needed. No other RFC
        Editor instructions are specified elsewhere in this document.</t>

  <t>Artwork in this document contains shorthand references to drafts in
        progress. Please apply the following replacements: <list style="symbols">
    <t>
      <spanx style="verb">I-D.ietf-netconf-crypto-types</spanx> --&gt;
            the assigned RFC value for draft-ietf-netconf-crypto-types</t>

    <t>
      <spanx style="verb">I-D.ietf-netconf-tls-client-server</spanx>
            --&gt; the assigned RFC value for
            draft-ietf-netconf-tls-client-server</t>

    <t>
      <spanx style="verb">zzzz</spanx> --&gt; the assigned RFC value
            for this draft</t>
  </list> target="RFC8342"/>.
      </t>
    </section>

<section title="Design
    <section>
      <name>Design of the Syslog Model"> Model</name>
      <t>
    The syslog model was designed by comparing various syslog features
    implemented by various vendors' vendors in different implementations.
      </t>
      <t>
    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. Vendors
    therefore, 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. <xref target="extending_facilities">Extending Facilities</xref> shows an
    examples of how that can be realized.
      </t>
      <t>Syslog consists of originators and collectors. The following diagram
      shows syslog messages flowing from originators, originators to collectors where
      filtering can take place.</t>

<figure>
  <artwork

     <figure title="Syslog Processing Flow"><artwork name="Syslog Process Flow" align="left"><![CDATA[
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>

  <postamble>Figure 1. Syslog Processing Flow</postamble>
</figure> +----------------+]]></artwork></figure>
     <t>Collectors are configured using the leaves in the syslog model
      "actions" container which that correspond to each message collector:</t>

<t>
  <list style="empty">
      <ul spacing="normal">
        <li>
          <t>console</t>
        </li>
        <li>
          <t>log file(s)</t>
        </li>
        <li>
          <t>remote relay(s)/collector(s)</t>
  </list>
</t>
        </li>
      </ul>
<!-- [rfced] What field is "[RFC5424] field" referring to in this sentence?

Original:
   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 [RFC5424] field.
-->
      <t>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
      <xref target="RFC5424"/> field.</t>
      <t>A syslog message is processed if: <figure>
  <artwork><![CDATA[ </t>

<!-- [rfced] This text has been changed from an artwork element
to a sourcecode element with type="pseudocode". Please let us
know if you prefer to change it to running text (within a <t>
element).

Original:
   A syslog message is processed if:

          There is an element of facility-list (F, S) where
              the message facility matches F
              and the message severity matches S
          and/or the message text matches the regex pattern (if it
              is present)
       ]]>  </artwork>
</figure>
</t>

Perhaps:
   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 type="pseudocode"><![CDATA[
       There is an element of facility-list (F, S) where
           the message facility matches F
           and the message severity matches S
       and/or the message text matches the regex pattern (if it
           is present)]]></sourcecode>

      <t>The facility is one of a specific syslog-facility, syslog-facility or all
      facilities.</t>
      <t>
	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, UDP or TLS based TLS-based sessions. The user can
	configure multiple relays or collectors, but they have to use
	the same transport.
      </t>
      <t>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>
	Many vendors extend the list of facilities available for
	logging in their implementation. An example is included in
	<xref target="extending_facilities">Extending
	Facilities</xref>. "Extending Facilities"
	(<xref target="extending_facilities"/>).
      </t>

<section title="Syslog Module">
      <section>
        <name>Syslog Module</name>
        <t>
    A simplified tree representation of the data model is used in
    this document. Please see <xref target="RFC8340"/> for tree
    diagram notation.
        </t>
        <figure>
          <name>Tree Diagram for Syslog Model</name>
  <artwork><![CDATA[

<!-- [rfced] FYI, in the YANG tree, this line was followed by a
floating question mark, which we moved up to the preceding line.
This line exceeds the character limit (69 chars for <sourcecode>)
by 3 characters. For updating it, which option do you prefer?

Original:
                     |  |  |       {certificate-expiration-notification}
 ?

Current:
                       |  |  |       {certificate-expiration-notification}?

Option A (using the "\" line wrapping notation as used in Appendix A.1
and adding the note about line wrapping for formatting only):

                       |  |  |       {certificate-expiration-notificati\
on}?

Option B (moving it 3 spaces to the left):
                       |  |  |    {certificate-expiration-notification}?
-->

          <sourcecode type="yangtree"><![CDATA[
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-notification}
?       {certificate-expiration-notification}?
                    |  |  |  +-- 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

  ]]>
  </artwork>
]]></sourcecode>
        </figure>
      </section>
    </section>

<section title="Syslog
    <section>
      <name>Syslog YANG Module">
<section title="The Module</name>
      <section>
        <name>The ietf-syslog Module"> Module</name>
        <t>
    This module imports typedefs from <xref target="RFC6991"/>, <xref target="RFC8343"/>, groupings from <xref
    target="I-D.ietf-netconf-crypto-types"/>, target="RFC9640"/>, and <xref
    target="I-D.ietf-netconf-tls-client-server"/>, and it target="RFC9645"/>. It references
    <xref target="RFC5424"/>, <xref target="RFC5425"/>, <xref target="RFC5426"/>, <xref target="RFC5848"/>, <xref target="RFC8089"/>, <xref target="RFC8174"/>, and <xref target="Std-1003.1-2008"/>.
        </t>
<!-- [rfced] We have the following questions regarding the YANG module.

a) What do the numbers in parentheses refer to in various descriptions?
They seem to refer to the numerical codes in Table 1 of RFC 5424;
should a sentence be added so that this is clear to readers?

Original:
"The facility for local use 0 messages (16).";

b) May we change two instances of "the compare" to
"the compare operation" to match previous use?

Original:
"The compare can be used to specify the comparison
operator that should be used to compare the syslog
message severity with the specified severity."

Perhaps:
"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."
-->

<!--[rfced] Note that the YANG module has been updated per the
formatting option of pyang.  Please let us know any concerns.
-->
<figure>
<name>Sylog
          <name>Syslog YANG Model</name>
<artwork><![CDATA[
<CODE BEGINS> file "ietf-syslog@2024-09-18.yang" Module</name>
          <sourcecode type="yang" markers="true" name="ietf-syslog@2025-03-03.yang"><![CDATA[
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
      "I-D.ietf-netconf-tls-client-server:
      "RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
  }
  import ietf-crypto-types {
    prefix ct;
    reference
      "I-D.ietf-netconf-crypto-types:
      "RFC 9640: YANG Data Types and Groupings for Cryptography";
  }

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

     Editor:   Mahesh Jethanandani
     <mailto:mjethanandani@gmail.com>

     Editor:   Joe Clarke
     <mailto:jclarke@cisco.com>

     Editor:   Kiran Agrahara Sreenivasa
     <mailto:kirankoushik.agraharasreenivasa@verizonwireless.com>

     Editor:   Clyde Wildes
     <mailto:clyde@clydewildes.com>";
  description
    "This module contains a collection of YANG definitions
     for syslog configuration.

     Copyright (c) 2024 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 zzzz
     (https://www.rfc-editor.org/info/rfczzzz); 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 2024-09-18 2025-03-03 {
    description
      "Initial Revision";
    reference
      "RFC zzzz: 9742: Syslog YANG Model"; 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
       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' indicating indicates that the
           system is unusable.";
      }
      enum alert {
        value 1;
        description
          "The severity level 'Alert' indicating indicates that an
           action must be taken immediately.";
      }
      enum critical {
        value 2;
        description
          "The severity level 'Critical' indicating indicates a
           critical condition.";
      }
      enum error {
        value 3;
        description
          "The severity level 'Error' indicating indicates an error
           condition.";
      }
      enum warning {
        value 4;
        description
          "The severity level 'Warning' indicating indicates a warning
           condition.";
      }
      enum notice {
        value 5;
        description
          "The severity level 'Notice' indicating indicates a normal
           but significant condition.";
      }
      enum info {
        value 6;
        description
          "The severity level 'Info' indicating indicates an
           informational message.";
      }
      enum debug {
        value 7;
        description
          "The severity level 'Debug' indicating 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 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 (0).";
    reference
      "RFC 5424: The Syslog Protocol";
  }

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

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

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

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

  identity syslog {
    base syslog-facility;
    description
      "The facility for messages generated internally by a syslogd
       facility (5).";
    reference
      "RFC 5424: The Syslog Protocol";
  }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  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
       true, the message will be logged.";
  }

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

  identity stop {
    base action;
    description
      "This identity specifies that if the compare operation is
       true
       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 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 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"; 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 the compare that is done and the action leaf
         specifies the intended result.
         Example: compare->equals and action->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 selector, which is used to
       select log messages for the log-actions (console, file,
       remote, etc.).  Choose one or both of the following:
          facility [<facility> <severity>...]
          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-1003.1-2008 Regular Expressions";
    }
  }

  grouping structured-data {
    description
      "This grouping defines the syslog structured data option 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
               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 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 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.)."; 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.";
              }
            }
          }
        }
      }
    }
  }
}
<CODE ENDS>

]]></artwork>
]]></sourcecode>
        </figure>
      </section>
    </section>

<section title="Usage Examples">
<section title="Syslog
    <section>
      <name>Usage Examples</name>
      <section>
        <name>Syslog Configuration for Severity Critical"> Critical</name>
        <figure>
          <name>Syslog Configuration for Severity Critical</name>
          <artwork><![CDATA[
[note: '\' line wrapping for formatting only]

<!--
     Enable console logging of syslogs of severity critical
-->

<?xml version="1.0" encoding="UTF-8"?>
<syslog xmlns="urn:ietf:params:xml:ns:yang:ietf-syslog">
  <actions>
    <console>
      <filter>
        <facility-list>
          <facility>all</facility>
          <severity>critical</severity>
        </facility-list>
      </filter>
    </console>
  </actions>
</syslog>

]]></artwork>
</syslog>]]></artwork>
        </figure>
      </section>
<section title="Remote
      <section>
        <name>Remote Syslog Configuration"> Configuration</name>
        <figure>
          <name>Remote Syslog Configuration</name>
          <artwork><![CDATA[
[note: '\' line wrapping for formatting only]

<!--
      Enable remote logging of syslogs to udp destination
      foo.example.com for facility auth, severity error
-->
<?xml version="1.0" encoding="UTF-8"?>
<syslog xmlns="urn:ietf:params:xml:ns:yang:ietf-syslog">
  <actions>
    <remote>
      <destination>
        <name>remote1</name>
        <udp>
	  <udp>
            <address>foo.example.com</address>
	  </udp>
        </udp>
        <filter>
          <facility-list>
            <facility>auth</facility>
            <severity>error</severity>
          </facility-list>
        </filter>
      </destination>
    </remote>
  </actions>
</syslog>

]]></artwork>
</syslog>]]></artwork>
        </figure>
      </section>
    </section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>The authors wish to thank the following who commented on this
      proposal:</t>

<t>Andy Bierman, Martin Bjorklund, Alex Campbell, Alex Clemm,
      Francis Dupont, Jim Gibson, Jeffrey Haas, Bob Harold, John
      Heasley, Giles Heron, Lisa Huang, Mahesh Jethanandani, Warren
      Kumari, Jeffrey K Lange, Jan Lindblad, Chris Lonvick, Alexey
      Melnikov, Kathleen Moriarty, Tom Petch, Adam Roach, Juergen
      Schoenwaelder, Phil Shafer, Yaron Sheffer, Jason Sterne, Peter
      Van Horne, Kent Watsen, Bert Wijnen, Dale R Worley, and
      Aleksandr Zhdankin.</t>
</section>

<!-- Possibly a 'Contributors' section ... -->

<section anchor="IANA" title="IANA Considerations">
<section title="The anchor="IANA">
      <name>IANA Considerations</name>
      <section>
        <name>The IETF XML Registry"> Registry</name>
        <t>This document registers one URI in the IETF "IETF XML registry <xref target="RFC3688"/>
.
Following Registry", following the format defined in <xref target="RFC3688"/>
,
the following registration is requested:</t>

<t>
<figure>
<artwork><![CDATA[
   URI: urn:ietf:params:xml:ns:yang:ietf-syslog
   Registrant Contact: The IESG.
   XML: N/A, target="RFC3688"/>:</t>
	<dl newline="false" spacing="compact">
	  <dt>URI:</dt><dd>urn:ietf:params:xml:ns:yang:ietf-syslog</dd>
	  <dt>Registrant Contact:</dt><dd>The IESG.</dd>
	  <dt>XML:</dt><dd>N/A; the requested URI is an XML namespace.
]]></artwork>
</figure>
</t> namespace.</dd>
	</dl>

      </section>

<section title="The
      <section>
        <name>The YANG Module Names Registry"> Registry</name>
        <t>This document registers one YANG module in the YANG "YANG Module Names Names"
        registry <xref target="RFC8525"/>
. Following target="RFC8525"/>, following the format in <xref target="RFC7950"/>
,
        the following registration is requested:</t>

<t>
<figure>
<artwork><![CDATA[
   name:         ietf-syslog
   namespace:    urn:ietf:params:xml:ns:yang:ietf-syslog
   prefix:       syslog
   reference:    RFC zzzz

]]></artwork>
</figure>
</t> target="RFC7950"/>:</t>
	<dl spacing="compact" newline="false">
	  <dt>Name:</dt><dd>ietf-syslog</dd>
	  <dt>Namespace:</dt><dd>urn:ietf:params:xml:ns:yang:ietf-syslog</dd>
	  <dt>Prefix:</dt><dd>syslog</dd>
	  <dt>Reference:</dt><dd>RFC 9742</dd>
	</dl>

      </section>
    </section>

<section title="Security Considerations">
    <section>
      <name>Security Considerations</name>
      <t>
  This section is modeled after the template defined in <xref section="3.7.1" target="RFC8407"/>.
      </t>
      <t>
<!-- DNE -->
The "ietf-syslog" YANG module specified in this document defines a schema for data model that is designed to be accessed via YANG-based network management protocols such as NETCONF <xref target="RFC6241"/> and or RESTCONF <xref target="RFC8040"/>. These protocols have The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport layers (e.g., is Secure Shell (SSH) <xref target="RFC4252"/>, TLS <xref target="RFC8446"/>, and
    QUIC <xref target="RFC9000"/>) target="RFC4252"/>. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement mutual
    authentication. secure transport is TLS <xref target="RFC8446"/>.
<!-- End of DNE -->
      </t>
      <t>
<!-- DNE -->
    The NETCONF access control model Network Configuration Access Control Model (NACM) <xref
    target="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>
<!-- End of DNE -->
      <t>
    This module imports groupings from ietf-crypto-types YANG module
    defined in <xref target="I-D.ietf-netconf-crypto-types">YANG target="RFC9640">YANG
    Groupings for Crypto Types</xref>. Security considerations
    described in that document apply to this module also.
      </t>
      <t>
<!-- DNE -->
    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).  These data nodes should be considered sensitive or
    vulnerable in all network environments.
<!-- End of DNE -->

<!--[rfced] Security Considerations: This text does not
exactly match the text provided for security
considerations of documents that contain YANG modules:
https://wiki.ietf.org/group/ops/yang-security-guidelines
Should this document be updated to match those?
For example: usage of "all" vs. "some" and the additional sentences
in the 5th paragraph (which start with "Logging" and "If logging").

Original:
   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).  These data nodes should be considered sensitive or
   vulnerable in all network environments.  Logging in particular is
   used to assess the state of systems and can be used to indicate a
   network compromise.  If logging were to be disabled through malicious
   means, attacks may not be readily detectable.  Therefore write
   operations (e.g., edit-config) to these data nodes without proper
   protection can have a negative effect on network operations and on
   network security.

Corresponding text on https://wiki.ietf.org/group/ops/yang-security-guidelines:

   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). These data nodes may be considered sensitive or vulnerable in
   some network environments. Write operations (e.g., edit-config) to these
   data nodes without proper protection can have a negative effect on network
   operations. These are the subtrees and data nodes and their
   sensitivity/vulnerability:
-->
Logging in particular is used to assess the state of systems and can be used
to indicate a network compromise.  If logging were to be disabled through
malicious means, attacks may not be readily detectable.  Therefore, write
operations (e.g., edit-config) to these data nodes without proper protection
can have a negative effect on network operations and on network security.
      </t>
      <t>
    In addition addition, there are data nodes that require careful analysis and
      review. These are the subtrees and data nodes and their
      sensitivity/vulnerability:

      <list hangIndent="6" style="hanging">
	<t hangText=" facility-filter/pattern-match:">When

      </t>
      <dl newline="false" spacing="normal">
        <dt> facility-filter/pattern-match:</dt>
        <dd>When writing
	this node, implementations MUST <bcp14>MUST</bcp14> ensure that the regular
	expression pattern match is not constructed to cause a regular
	expression denial of service denial-of-service attack due to a pattern that
	causes the regular expression implementation to work very
	slowly (exponentially related to input size).
	</t>

	<t hangText=" remote/destination/signing/cert-signer:">When
	</dd>
        <dt> remote/destination/signing/cert-signer:</dt>
        <dd>When writing this subtree, implementations MUST NOT <bcp14>MUST NOT</bcp14>
        specify a private key that is used for any other purpose.</t>
      </list>
  </t> purpose.</dd>
      </dl>
      <t>
<!-- DNE -->
    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. These
    are the subtrees and data nodes and their
    sensitivity/vulnerability:

    <list hangIndent="6" style="hanging">
      <t hangText=" remote/destination/transport:">This
<!-- End of DNE -->
      </t>
      <dl newline="false" spacing="normal">
        <dt> remote/destination/transport:</dt>
        <dd>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, host will allow a malicious user to spam the
      host on that port.
      </t>

      <t hangText=" remote/destination/signing:">This
      </dd>
        <dt> remote/destination/signing:</dt>
        <dd>This subtree contains
      information about the syslog message signing properties properties,
      including signing certificate information.
      </t>
    </list>
  </t>
      </dd>
      </dl>
      <t>
    There are no RPC operations defined in this YANG module.
      </t>
    </section>
  </middle>
  <back>
<references title="Normative References">
<?rfc include="reference.I-D.ietf-netconf-crypto-types.xml"?>

<?rfc include="reference.I-D.ietf-netconf-tls-client-server.xml"?>

<?rfc include="reference.RFC.8343.xml"?>

<?rfc include="reference.RFC.2119.xml"?>

<?rfc include="reference.RFC.3688.xml"?>

<?rfc include="reference.RFC.4252.xml"?>

<?rfc include="reference.RFC.5424.xml"?>

<?rfc include="reference.RFC.5425.xml"?>

<?rfc include="reference.RFC.5426.xml"?>

<?rfc include="reference.RFC.5848.xml"?>

<?rfc include="reference.RFC.6241.xml"?>

<?rfc include="reference.RFC.6991.xml"?>

<?rfc include="reference.RFC.8525.xml"?>

<?rfc include="reference.RFC.7950.xml"?>

<?rfc include="reference.RFC.8040.xml"?>

<?rfc include="reference.RFC.8089.xml"?>

<?rfc include="reference.RFC.8174.xml"?>

<?rfc include="reference.RFC.8407.xml"?>

<?rfc include="reference.RFC.8341.xml"?>

<?rfc include="reference.RFC.8446.xml"?>

<?rfc include="reference.RFC.9000.xml"?>
    <references>
      <name>References</name>
      <references>
        <name>Normative References</name>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9640.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9645.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8343.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.3688.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4252.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5424.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5425.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5426.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5848.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6241.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6991.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8525.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7950.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8040.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8089.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8407.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8341.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8446.xml"/>

<!-- [rfced] References

a) We have updated the Security Considerations section to reflect the
guidelines shown here:
https://wiki.ietf.org/group/ops/yang-security-guidelines.
As a result, RFC 9000 has been removed from the Normative References. Please
let us know if you prefer to cite it elsewhere.

b) Please review the following reference. We note that a newer version of this
standard was published in 2024; would you like to update this reference
to the most current version?

Original:
   [Std-1003.1-2008]
              Group, I. A. T. O., ""Chapter 9: Regular Expressions". The
              Open Group Base Specifications Issue 6, IEEE Std
              1003.1-2008, 2016 Edition.", September 2016,
              <http://pubs.opengroup.org/onlinepubs/9699919799/>.

Perhaps:
   [Std-1003.1-2024]
              The Open Group, "Chapter 9: Regular Expressions", The Open
              Group Base Specifications Issue 8, IEEE Std 1003.1-2024,
              2024, <https://pubs.opengroup.org/onlinepubs/9799919799/>.
-->

        <reference anchor="Std-1003.1-2008" target="http://pubs.opengroup.org/onlinepubs/9699919799/"> target="https://pubs.opengroup.org/onlinepubs/9699919799.2016edition/">
          <front>
            <title>"Chapter 9: Regular Expressions". Expressions" The Open Group Base
          Specifications Issue 6, IEEE Std 1003.1-2008, 2016 Edition.</title>

<author fullname="IEEE and The Open Group"> Edition</title>
            <author>
              <organization>The Open Group</organization>
            </author>
            <date month="September" year="2016"/>
          </front>
        </reference>
      </references>

<references title="Informative References">

<?rfc include="reference.RFC.8340.xml"?>
<?rfc include="reference.RFC.8342.xml"?>

      <references>
        <name>Informative References</name>

        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8340.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8342.xml"/>

      </references>
    </references>
    <section anchor="tree-diagrams" title="Tree Diagrams"> anchor="tree-diagrams">
      <name>Tree Diagrams</name>
      <section anchor="complete-tree-diagram" title="Complete anchor="complete-tree-diagram">
        <name>Complete Tree Diagram">
    <figure>
      <artwork align="left"><![CDATA[ Diagram</name>

<!-- [rfced] Please review the line wrapping in Appendix A.1.
Specifically, the original contained extra line breaks that were
apparently not intended (e.g., before "ivate-key?"). We have updated
the tree diagram to remove the extraneous line breaks. Please review;
see https://www.rfc-editor.org/authors/rfc9742-rfcdiff.html
and the examples below. (FYI, two hyphens are changed to one hyphen
below for the sake of inclusion as a comment in the XML file.)

Original:
                 |           |     |        |     |  |  +-rw cleartext\
   -pr
   ivate-key?
                 |           |     |        |     |  |          binary
                 |           |     |        |     |  +-:(hidden-privat\
   e-k
   ey)
                 |           |     |        |     |  |        {hidden-p\
   riv
   ate-keys}?

Current:
		 |           |     |        |     |  |  +-rw cleartext\
   -private-key?
                 |           |     |        |     |  |          binary
                 |           |     |        |     |  +-:(hidden-privat\
   e-key)
                 |           |     |        |     |  |        {hidden-p\
   rivate-keys}?
-->

        <sourcecode type="yangtree"><![CDATA[
[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-s
upported}?
s-supported}?
              |           |     |        |  +--rw inline-definition
              |           |     |        |     +--rw public-key-form\
at?
              |           |     |        |     |       identityref
              |           |     |        |     +--rw public-key?
              |           |     |        |     |       binary
              |           |     |        |     +--rw private-key-for\
mat
?
mat?
              |           |     |        |     |       identityref
              |           |     |        |     +--rw (private-key-ty\
pe)
              |           |     |        |     |  +--:(cleartext-pri\
vat
e-key)
vate-key)
              |           |     |        |     |  |        {cleartex\
t-p
rivate-keys}?
t-private-keys}?
              |           |     |        |     |  |  +--rw cleartext\
-pr
ivate-key?
-private-key?
              |           |     |        |     |  |          binary
              |           |     |        |     |  +--:(hidden-privat\
e-k
ey)
e-key)
              |           |     |        |     |  |        {hidden-p\
riv
ate-keys}?
rivate-keys}?
              |           |     |        |     |  |  +--rw hidden-pr\
iva
te-key?
ivate-key?
              |           |     |        |     |  |          empty
              |           |     |        |     |  +--:(encrypted-pri\
vat
e-key)
vate-key)
              |           |     |        |     |           {encrypte\
d-p
rivate-keys}?
d-private-keys}?
              |           |     |        |     |     +--rw encrypted\
-pr
ivate-key
-private-key
              |           |     |        |     |        +--rw encryp\
ted
-by
ted-by
              |           |     |        |     |        +--rw encryp\
ted
-value-format
ted-value-format
              |           |     |        |     |        |       iden\
tit
yref
tityref
              |           |     |        |     |        +--rw encryp\
ted
-value
ted-value
              |           |     |        |     |                bina\
ry
              |           |     |        |     +--rw cert-data?
              |           |     |        |     |       end-entity-ce\
rt-
cms
rt-cms
              |           |     |        |     +---n certificate-exp\
ira
tion
iration
              |           |     |        |     |       {certificate-\
exp
iration-notification}?
expiration-notification}?
              |           |     |        |     |  +-- expiration-dat\
e
              |           |     |        |     |          yang:date-\
and
-time
and-time
              |           |     |        |     +---x generate-csr
              |           |     |        |             {csr-generati\
on}
?
on}?
              |           |     |        |        +---w input
              |           |     |        |        |  +---w csr-forma\
t
              |           |     |        |        |  |       identit\
yre
f
yref
              |           |     |        |        |  +---w csr-info
              |           |     |        |        |          csr-inf\
o
              |           |     |        |        +--ro output
              |           |     |        |           +--ro (csr-type\
)
              |           |     |        |              +--:(p10-csr\
)
              |           |     |        |                 +--ro p10\
-cs
r?
-csr?
              |           |     |        |                         p\
10-
csr
10-csr
              |           |     |        +--:(central-keystore)
              |           |     |                 {central-keystore-\
sup
ported,asymmetric-keys}?
supported,asymmetric-keys}?
              |           |     |           +--rw central-keystore-r\
efe
rence
eference
              |           |     |              +--rw asymmetric-key?\

              |           |     |              |       ks:central-as\
ymm
etric-key-ref
ymmetric-key-ref
              |           |     |              |       {central-keys\
tor
e-supported,asymmetric-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-s
upported}?
s-supported}?
              |           |     |        |  +--rw inline-definition
              |           |     |        |     +--rw public-key-form\
at?
              |           |     |        |     |       identityref
              |           |     |        |     +--rw public-key?
              |           |     |        |     |       binary
              |           |     |        |     +--rw private-key-for\
mat
?
mat?
              |           |     |        |     |       identityref
              |           |     |        |     +--rw (private-key-ty\
pe)
              |           |     |        |        +--:(cleartext-pri\
vat
e-key)
vate-key)
              |           |     |        |        |        {cleartex\
t-p
rivate-keys}?
t-private-keys}?
              |           |     |        |        |  +--rw cleartext\
-pr
ivate-key?
-private-key?
              |           |     |        |        |          binary
              |           |     |        |        +--:(hidden-privat\
e-k
ey)
e-key)
              |           |     |        |        |        {hidden-p\
riv
ate-keys}?
rivate-keys}?
              |           |     |        |        |  +--rw hidden-pr\
iva
te-key?
ivate-key?
              |           |     |        |        |          empty
              |           |     |        |        +--:(encrypted-pri\
vat
e-key)
vate-key)
              |           |     |        |                 {encrypte\
d-p
rivate-keys}?
d-private-keys}?
              |           |     |        |           +--rw encrypted\
-pr
ivate-key
-private-key
              |           |     |        |              +--rw encryp\
ted
-by
ted-by
              |           |     |        |              +--rw encryp\
ted
-value-format
ted-value-format
              |           |     |        |              |       iden\
tit
yref
tityref
              |           |     |        |              +--rw encryp\
ted
-value
ted-value
              |           |     |        |                      bina\
ry
              |           |     |        +--:(central-keystore)
              |           |     |                 {central-keystore-\
sup
ported,asymmetric-keys}?
supported,asymmetric-keys}?
              |           |     |           +--rw central-keystore-r\
efe
rence?
eference?
              |           |     |                   ks:central-asymm\
etr
ic-key-ref
etric-key-ref
              |           |     +--:(tls12-psk)
              |           |     |        {client-ident-tls12-psk}?
              |           |     |  +--rw tls12-psk
              |           |     |     +--rw (inline-or-keystore)
              |           |     |     |  +--:(inline)
              |           |     |     |  |        {inline-definition\
s-s
upported}?
s-supported}?
              |           |     |     |  |  +--rw inline-definition
              |           |     |     |  |     +--rw key-format?
              |           |     |     |  |     |       identityref
              |           |     |     |  |     +--rw (key-type)
              |           |     |     |  |        +--:(cleartext-sym\
met
ric-key)
metric-key)
              |           |     |     |  |        |  +--rw cleartext\
-sy
mmetric-key?
-symmetric-key?
              |           |     |     |  |        |          binary
              |           |     |     |  |        |          {cleart\
ext
-symmetric-keys}?
ext-symmetric-keys}?
              |           |     |     |  |        +--:(hidden-symmet\
ric
-key)
ric-key)
              |           |     |     |  |        |        {hidden-s\
ymm
etric-keys}?
ymmetric-keys}?
              |           |     |     |  |        |  +--rw hidden-sy\
mme
tric-key?
mmetric-key?
              |           |     |     |  |        |          empty
              |           |     |     |  |        +--:(encrypted-sym\
met
ric-key)
metric-key)
              |           |     |     |  |                 {encrypte\
d-s
ymmetric-keys}?
d-symmetric-keys}?
              |           |     |     |  |           +--rw encrypted\
-sy
mmetric-key
-symmetric-key
              |           |     |     |  |              +--rw encryp\
ted
-by
ted-by
              |           |     |     |  |              +--rw encryp\
ted
-value-format
ted-value-format
              |           |     |     |  |              |       iden\
tit
yref
tityref
              |           |     |     |  |              +--rw encryp\
ted
-value
ted-value
              |           |     |     |  |                      bina\
ry
              |           |     |     |  +--:(central-keystore)
              |           |     |     |           {central-keystore-\
sup
ported,symmetric-keys}?
supported,symmetric-keys}?
              |           |     |     |     +--rw central-keystore-r\
efe
rence?
eference?
              |           |     |     |             ks:central-symme\
tri
c-key-ref
tric-key-ref
              |           |     |     +--rw id?
              |           |     |             string
              |           |     +--:(tls13-epsk)
              |           |              {client-ident-tls13-epsk}?
              |           |        +--rw tls13-epsk
              |           |           +--rw (inline-or-keystore)
              |           |           |  +--:(inline)
              |           |           |  |        {inline-definition\
s-s
upported}?
s-supported}?
              |           |           |  |  +--rw inline-definition
              |           |           |  |     +--rw key-format?
              |           |           |  |     |       identityref
              |           |           |  |     +--rw (key-type)
              |           |           |  |        +--:(cleartext-sym\
met
ric-key)
metric-key)
              |           |           |  |        |  +--rw cleartext\
-sy
mmetric-key?
-symmetric-key?
              |           |           |  |        |          binary
              |           |           |  |        |          {cleart\
ext
-symmetric-keys}?
ext-symmetric-keys}?
              |           |           |  |        +--:(hidden-symmet\
ric
-key)
ric-key)
              |           |           |  |        |        {hidden-s\
ymm
etric-keys}?
ymmetric-keys}?
              |           |           |  |        |  +--rw hidden-sy\
mme
tric-key?
mmetric-key?
              |           |           |  |        |          empty
              |           |           |  |        +--:(encrypted-sym\
met
ric-key)
metric-key)
              |           |           |  |                 {encrypte\
d-s
ymmetric-keys}?
d-symmetric-keys}?
              |           |           |  |           +--rw encrypted\
-sy
mmetric-key
-symmetric-key
              |           |           |  |              +--rw encryp\
ted
-by
ted-by
              |           |           |  |              +--rw encryp\
ted
-value-format
ted-value-format
              |           |           |  |              |       iden\
tit
yref
tityref
              |           |           |  |              +--rw encryp\
ted
-value
ted-value
              |           |           |  |                      bina\
ry
              |           |           |  +--:(central-keystore)
              |           |           |           {central-keystore-\
sup
ported,symmetric-keys}?
supported,symmetric-keys}?
              |           |           |     +--rw central-keystore-r\
efe
rence?
eference?
              |           |           |             ks:central-symme\
tri
c-key-ref
tric-key-ref
              |           |           +--rw external-identity
              |           |           |       string
              |           |           +--rw hash?
              |           |           |       tlscmn:epsk-supported-\
has
h
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\
ort
ed}?
orted}?
              |           |  |     |  +--rw inline-definition
              |           |  |     |     +--rw certificate* [name]
              |           |  |     |        +--rw name
              |           |  |     |        |       string
              |           |  |     |        +--rw cert-data
              |           |  |     |        |       trust-anchor-cer\
t-c
ms
t-cms
              |           |  |     |        +---n certificate-expira\
tio
n
tion
              |           |  |     |                {certificate-exp\
ira
tion-notification}?
iration-notification}?
              |           |  |     |           +-- expiration-date
              |           |  |     |                   yang:date-and\
-ti
me
-time
              |           |  |     +--:(central-truststore)
              |           |  |              {central-truststore-supp\
ort
ed,certificates}?
orted,certificates}?
              |           |  |        +--rw central-truststore-refer\
enc
e?
ence?
              |           |  |                ts:central-certificate\
-ba
g-ref
-bag-ref
              |           |  +--rw ee-certs! {server-auth-x509-cert}\
?
              |           |  |  +--rw (inline-or-truststore)
              |           |  |     +--:(inline)
              |           |  |     |        {inline-definitions-supp\
ort
ed}?
orted}?
              |           |  |     |  +--rw inline-definition
              |           |  |     |     +--rw certificate* [name]
              |           |  |     |        +--rw name
              |           |  |     |        |       string
              |           |  |     |        +--rw cert-data
              |           |  |     |        |       trust-anchor-cer\
t-c
ms
t-cms
              |           |  |     |        +---n certificate-expira\
tio
n
tion
              |           |  |     |                {certificate-exp\
ira
tion-notification}?
iration-notification}?
              |           |  |     |           +-- expiration-date
              |           |  |     |                   yang:date-and\
-ti
me
-time
              |           |  |     +--:(central-truststore)
              |           |  |              {central-truststore-supp\
ort
ed,certificates}?
orted,certificates}?
              |           |  |        +--rw central-truststore-refer\
enc
e?
ence?
              |           |  |                ts:central-certificate\
-ba
g-ref
-bag-ref
              |           |  +--rw raw-public-keys!
              |           |  |       {server-auth-raw-public-key}?
              |           |  |  +--rw (inline-or-truststore)
              |           |  |     +--:(inline)
              |           |  |     |        {inline-definitions-supp\
ort
ed}?
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\
ort
ed,public-keys}?
orted,public-keys}?
              |           |  |        +--rw central-truststore-refer\
enc
e?
ence?
              |           |  |                ts:central-public-key-\
bag
-ref
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\
rit
hm
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}
?
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
      ]]></artwork>
    </figure>
]]></sourcecode>
      </section>
    </section>
    <section>
      <name>Implementer Guidelines</name>
      <section title="Implementer Guidelines">
<section anchor="extending_facilities" title="Extending Facilities"> anchor="extending_facilities">
        <name>Extending Facilities</name>
        <t>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 [RFC5424] and hence <xref target="RFC5424"/>. Thus, such facilities
        apply for local syslog-like logging functionality.</t>
        <t>The following is an example that shows how additional facilities
        could be added to the list of available facilities (in this example
        two (two facilities are added):</t>

<figure>
<artwork align="left"><![CDATA[
[note: '\' line wrapping for formatting only] added in this example):</t>

        <sourcecode type="yang" name="example-vendor-syslog-types@2025-03-03.yang"><![CDATA[
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

     E-mail:

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

  revision 2024-03-19 2025-03-03 {
    description
      "Version 1.0";
    reference
      "Vendor SYSLOG Syslog Types: SYSLOG Syslog YANG Model"; Module";
  }

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

  identity vendor_specific_type_2 {
    base syslog:syslog-facility;
    description
      "Adding vendor specific vendor-specific type 2 to syslog-facility";
  }
}
         ]]></artwork>
</figure>
}]]></sourcecode>
      </section>
<section title="Syslog
      <section>
        <name>Syslog Terminal Output"> Output</name>
        <t>Terminal output with requirements more complex than the console
  subtree currently provides, provides are expected to be supported via vendor
  extensions rather than handled via the file subtree.</t>
      </section>
<section title="Syslog
      <section>
        <name>Syslog File Naming Convention"> Convention</name>
        <t>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>When an active syslog file with a name specified by log-file/name, 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, can compress it, and can name the archive file &lt;log-file/
  name>.0.gz.
  name&gt;.0.gz.  The logging system can then open a new active syslog
  file &lt;log-file/name>.</t> &lt;log-file/name&gt;.</t>
        <t>When the new syslog file reaches either of the size limits referenced
  above, &lt;log-file/name>.0.gz &lt;log-file/name&gt;.0.gz can be renamed &lt;log-file/name>.1.gz &lt;log-file/name&gt;.1.gz and
  the new syslog file can be closed, compressed compressed, and renamed &lt;log-file/
  name>.0.gz.
  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>.&lt;n>.gz &lt;log-file/name&gt;.&lt;n&gt;.gz can be
  renamed to &lt;log-file/name>.&lt;n &lt;log-file/name&gt;.&lt;n + 1>.gz.</t>

<t>Removal 1&gt;.gz.</t>

<!--[rfced] FYI, we have updated this list as follows. Please review
whether this conveys the intended meaning.

Original:
   Removal of archive log files could occur when either or both:</t>

<t>- both:

   - log-file/number-of-files 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.</t>

<t>- overwritten.

   - log-file/retention 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.</t>
   time.

Current:
   Removal of archive log files could occur when either or both:

   *  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.

   *  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.
-->
  <t>Removal of archive log files could occur when either or both:</t>
  <ul>
    <li>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>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">
      <name>Acknowledgements</name>
      <t>The authors wish to thank the following who commented on this
      proposal:</t>
      <t><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>
    <!-- Possibly a 'Contributors' section ... -->

    <!-- Change Log

v07 2016-03-20 CW     Converted the document to XML format and incorporated
                      changes from Martin Bjorklund and Tom Petch.

v08 2016-05-07 CW     Incorporated changes from Benoit Claise, Tom Petch,
                      and Mahesh Jethanandani.

v09 2016-07-08 CW     Incorporated changes from Jason Sterne, Tom Petch,
                      and Juergen Schoenwaelder.

v10 2016-10-30 CW     Incorporated changes from Juergen Schoenwaelder.

v11 2016-11-13 CW     Incorporated changes from Phil Shafer.

v12 2017-02-14 CW     Incorporated changes from Andy Bierman and Alex Campbell.

v13 2017-03-13 CW     Incorporated changes from various contributors.

v14 2017-03-27 CW     Incorporated changes from various contributors.

v15 2017-06-07 CW     Incorporated changes from various contributors.

v16 2017-08-11 CW     Incorporated changes from various contributors.

v17 2017-09-08 CW     Incorporated changes from various contributors.

v18 2017-12-08 CW     Incorporated changes from various contributors.

v19 2018-01-12 CW     Incorporated changes from various contributors.

v20 2018-02-09 CW     Incorporated changes from various contributors.

v21 2018-02-14 CW     Incorporated changes from various contributors.

v22 2018-02-21 CW     Incorporated changes from Yaron Sheffer and Ron Bonica.

v23 2018-03-01 CW     Incorporated changes from Kent. -->

<!-- [rfced] We noticed that the following term is used inconsistently. If
there are no objections, we will use the form on the right.

leafs vs. leaves
-->

<!-- [rfced] Please review the "Inclusive Language" portion of the online
Style Guide <https://www.rfc-editor.org/styleguide/part2/#inclusive_language>
and let us know if any changes are needed.  Updates of this nature typically
result in more precise language, which is helpful for readers.

Note that our script did not flag any words in particular, but this should
still be reviewed as a best practice.
-->

</back>
</rfc>