| RFC 0000 | Syslog Management | August 2020 |
| Wildes & Koushik | Standards Track | [Page] |
This document defines a YANG data model for the configuration of a syslog process. It is intended this model be used by vendors who implement syslog in their systems.¶
This is an Internet Standards Track document.¶
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.¶
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc0000.¶
Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved.¶
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.¶
This document defines a YANG [RFC7950] configuration data model that may be used to configure the syslog feature running on a system. YANG models can be used with network management protocols such as NETCONF [RFC6241] to install, manipulate, and delete the configuration of network devices.¶
The data model makes use of the YANG "feature" construct which allows implementations to support only those syslog features that lie within their capabilities.¶
This module can be used to configure the syslog application conceptual layers as implemented on the target system.¶
Essentially, a syslog process receives messages (from the kernel, processes, applications or other syslog processes) and processes them. The processing may involve logging to a local file, and/or displaying on console, and/or relaying to syslog processes on other machines. The processing is determined by the "facility" that originated the message and the "severity" assigned to the message by the facility.¶
Such definitions of syslog protocol are defined in [RFC5424], and are used in this RFC.¶
The YANG model in this document conforms to the Network Management Datastore Architecture defined in [draft-ietf-netmod-revised-datastores].¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
The term "originator" is defined in [RFC5424]: an "originator" generates syslog content to be carried in a message.¶
The term "relay" is defined in [RFC5424]: a "relay" forwards messages, accepting messages from originators or other relays and sending them to collectors or other relays¶
The term "collectors" is defined in [RFC5424]: a "collector" gathers syslog content for further analysis.¶
The term "action" refers to the processing that takes place for each syslog message received.¶
The YANG model in this document conforms to the Network Management Datastore Architecture defined in [RFC8342].¶
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.¶
Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements:¶
The syslog model was designed by comparing various syslog features implemented by various vendors' in different implementations.¶
This document addresses the common leafs between implementations and creates a common model, which can be augmented with proprietary features, if necessary. This model is designed to be very simple for maximum flexibility.¶
Some optional features are defined in this document to specify functionality that is present in specific vendor configurations.¶
Syslog consists of originators and collectors. The following diagram shows syslog messages flowing from originators, to collectors where filtering can take place.¶
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) |
+----------+ +----------+ +----------------+
Collectors are configured using the leaves in the syslog model "actions" container which correspond to each message collector:¶
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.¶
A syslog message is processed if:¶
There is an element of facility-list (F, S) where¶
The facility is one of a specific syslog-facility, or all facilities.¶
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 or block the message from being logged.¶
Many vendors extend the list of facilities available for logging in their implementation. An example is included in Extending Facilities (Appendix A.1).¶
A simplified graphical representation of the data model is used in this document. Please see [RFC8340] for tree diagram notation.¶
module: ietf-syslog
+--rw syslog!
+--rw actions
+--rw console! {console-action}?
| +--rw facility-filter
| | +--rw facility-list* [facility severity]
| | +--rw facility union
| | +--rw severity union
| | +--rw advanced-compare {select-adv-compare}?
| | +--rw compare? enumeration
| | +--rw action? enumeration
| +--rw pattern-match? string {select-match}?
+--rw file {file-action}?
| +--rw log-file* [name]
| +--rw name inet:uri
| +--rw facility-filter
| | +--rw facility-list* [facility severity]
| | +--rw facility union
| | +--rw severity union
| | +--rw advanced-compare {select-adv-compare}?
| | +--rw compare? enumeration
| | +--rw action? enumeration
| +--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 address? inet:host
| | +--rw port? inet:port-number
| +--:(tls)
| +--rw tls
| +--rw address? inet:host
| +--rw port? inet:port-number
| +--rw client-auth
| | +--rw (auth-type)?
| | +--:(certificate)
| | +--rw certificate? leafref
| +--rw server-auth
| | +--rw pinned-ca-certs? leafref
| | +--rw pinned-server-certs? leafref
| +--rw hello-params
| {tls-client-hello-params-config}?
| +--rw tls-versions
| | +--rw tls-version* identityref
| +--rw cipher-suites
| +--rw cipher-suite* identityref
+--rw facility-filter
| +--rw facility-list* [facility severity]
| +--rw facility union
| +--rw severity union
| +--rw advanced-compare {select-adv-compare}?
| +--rw compare? enumeration
| +--rw action? enumeration
+--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 algorithm?
| | | identityref
| | +--rw private-key?
| | | union
| | +--rw public-key?
| | | binary
| | +---x generate-private-key
| | | +---w input
| | | +---w algorithm?
| | | identityref
| | +--rw certificates
| | | +--rw certificate* [name]
| | | +--rw name string
| | | +--rw value? binary
| | +---x generate-certificate-signing-request
| | +---w input
| | | +---w subject binary
| | | +---w attributes? binary
| | +--ro output
| | +--ro certificate-signing-request
| | binary
| +--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
This module imports typedefs from [RFC6991], [RFC8343], groupings from [RFCYYY1], and [RFCYYY2], and it references [RFC5424], [RFC5425], [RFC5426], [RFC5848], [RFC8089], [RFC8174], and [Std-1003.1-2008].¶
<CODE BEGINS> file "ietf-syslog@2018-03-15.yang"
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
"RFC8343: A YANG Data Model
for Interface Management";
}
import ietf-tls-client {
prefix tlsc;
reference
"RFCYYY2:
YANG Groupings for TLS Clients and TLS Servers";
}
import ietf-keystore {
prefix ks;
reference
"RFCYYY1: YANG Data Model for a
Keystore Mechanism";
}
organization
"IETF NETMOD (Network Modeling) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
Editor: Kiran Agrahara Sreenivasa
<mailto:kirankoushik.agraharasreenivasa@
verizonwireless.com>
Editor: Clyde Wildes
<mailto:cwildes@cisco.com>";
description
"This module contains a collection of YANG definitions
for syslog configuration.
Copyright (c) 2018 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 Simplified BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
'OPTIONAL' in the module text are to be interpreted as
described in RFC 2119 (http://tools.ietf.org/html/rfc2119).
This version of this YANG module is part of RFC zzzz
(http://tools.ietf.org/html/rfczzzz); see the RFC itself for
full legal notices.";
revision 2018-03-15 {
description
"Initial Revision";
reference
"RFC zzzz: Syslog YANG Model";
}
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 that the
system is unusable.";
}
enum "alert" {
value 1;
description
"The severity level 'Alert' indicating that an action
must be taken immediately.";
}
enum "critical" {
value 2;
description
"The severity level 'Critical' indicating a critical
condition.";
}
enum "error" {
value 3;
description
"The severity level 'Error' indicating an error
condition.";
}
enum "warning" {
value 4;
description
"The severity level 'Warning' indicating a warning
condition.";
}
enum "notice" {
value 5;
description
"The severity level 'Notice' indicating a normal but
significant condition.";
}
enum "info" {
value 6;
description
"The severity level 'Info' indicating an informational
message.";
}
enum "debug" {
value 7;
description
"The severity level 'Debug' indicating a debug-level
message.";
}
}
description
"The definitions for Syslog message severity.
Note that a lower value is a higher severity. Comparisons of
equal-or-higher severity mean equal or lower numeric value";
reference
"RFC 5424: The Syslog Protocol";
}
identity syslog-facility {
description
"This identity is used as a base for all syslog facilities.";
reference
"RFC 5424: The Syslog Protocol";
}
identity kern {
base syslog-facility;
description
"The facility for kernel messages (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 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 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";
}
grouping severity-filter {
description
"This grouping defines the processing used to select
log messages by comparing syslog message severity using
the following processing rules:
- if 'none', do not match.
- if 'all', match.
- else compare message severity with the specified severity
according to the default compare rule (all messages of the
specified severity and greater match) or if the
select-adv-compare feature is present, use the
advance-compare rule.";
leaf severity {
type union {
type syslog-severity;
type enumeration {
enum none {
value 2147483647;
description
"This enum describes the case where no severities
are selected.";
}
enum all {
value -2147483648;
description
"This enum describes the case where all severities
are selected.";
}
}
}
mandatory true;
description
"This leaf specifies the syslog message severity.";
}
container advanced-compare {
when '../severity != "all" and
../severity != "none"' {
description
"The advanced compare container is not applicable for
severity 'all' or severity 'none'";
}
if-feature select-adv-compare;
leaf compare {
type enumeration {
enum equals {
description
"This enum specifies that the severity comparison
operation will be equals.";
}
enum equals-or-higher {
description
"This enum specifies that the severity comparison
operation will be equals or higher.";
}
}
default equals-or-higher;
description
"The compare 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 enumeration {
enum log {
description
"This enum specifies that if the compare operation is
true the message will be logged.";
}
enum block {
description
"This enum specifies that if the compare operation is
true the message will not be logged.";
}
}
default log;
description
"The action can be used to specify if the message should
be logged or blocked based on the outcome of the compare
operation.";
}
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 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 facility-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
which is used to select the format used to write log
messages.";
leaf structured-data {
if-feature structured-data;
type boolean;
default false;
description
"This leaf describes how log messages are written.
If true, messages will be written with one or more
STRUCTURED-DATA elements; if false, messages will be
written with STRUCTURED-DATA = NILVALUE.";
reference
"RFC 5424: The Syslog Protocol";
}
}
container syslog {
presence "Enables logging.";
description
"This container describes the configuration parameters for
syslog.";
container actions {
description
"This container describes the log-action parameters
for syslog.";
container console {
if-feature console-action;
presence "Enables logging to the console";
description
"This container describes the configuration parameters
for console logging.";
uses selector;
}
container file {
if-feature file-action;
description
"This container describes the configuration parameters for
file logging. If file-archive limits are not supplied, it
is assumed that the local implementation defined limits
will be used.";
list log-file {
key "name";
description
"This list describes a collection of local logging
files.";
leaf name {
type inet:uri {
pattern 'file:.*';
}
description
"This leaf specifies the name of the log file which
MUST use the uri scheme file:.";
reference
"RFC 8089: The file URI Scheme";
}
uses selector;
uses structured-data;
container file-rotation {
description
"This container describes the configuration
parameters for log file rotation.";
leaf number-of-files {
if-feature file-limit-size;
type uint32;
default 1;
description
"This leaf specifies the maximum number of log
files retained. Specify 1 for implementations
that only support one log file.";
}
leaf max-file-size {
if-feature file-limit-size;
type uint32;
units "megabytes";
description
"This leaf specifies the maximum log file size.";
}
leaf rollover {
if-feature file-limit-duration;
type uint32;
units "minutes";
description
"This leaf specifies the length of time that log
events should be written to a specific log file.
Log events that arrive after the rollover period
cause the current log file to be closed and a new
log file to be opened.";
}
leaf retention {
if-feature file-limit-duration;
type uint32;
units "minutes";
description
"This leaf specifies the length of time that
completed/closed log event files should be stored
in the file system before they are removed.";
}
}
}
}
container remote {
if-feature remote-action;
description
"This container describes the configuration parameters
for forwarding syslog messages to remote relays or
collectors.";
list destination {
key "name";
description
"This list describes a collection of remote logging
destinations.";
leaf name {
type string;
description
"An arbitrary name for the endpoint to connect to.";
}
choice transport {
mandatory true;
description
"This choice describes the transport option.";
case udp {
container udp {
description
"This container describes the UDP transport
options.";
reference
"RFC 5426: Transmission of Syslog Messages over
UDP";
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 ";
leaf address {
type inet:host;
description
"The leaf uniquely specifies the address of
the remote host. One of the following must be
specified: an ipv4 address, an ipv6 address,
or a host name.";
}
leaf port {
type inet:port-number;
default 6514;
description
"TCP port 6514 has been allocated as the default
port for syslog over TLS.";
}
uses tlsc:tls-client-grouping;
}
}
}
uses selector;
uses structured-data;
leaf facility-override {
type identityref {
base syslog-facility;
}
description
"If specified, this leaf specifies the facility used
to override the facility in messages delivered to
the remote server.";
}
leaf source-interface {
if-feature remote-source-interface;
type if:interface-ref;
description
"This leaf sets the source interface to be used to
send messages to the remote syslog server. If not
set, messages can be sent on any interface.";
}
container signing {
if-feature signed-messages;
presence
"If present, syslog-signing options is activated.";
description
"This container describes the configuration
parameters for signed syslog messages.";
reference
"RFC 5848: Signed Syslog Messages";
container cert-signers {
description
"This container describes the signing certificate
configuration for Signature Group 0 which covers
the case for administrators who want all Signature
Blocks to be sent to a single destination.";
list cert-signer {
key "name";
description
"This list describes a collection of syslog
message signers.";
leaf name {
type string;
description
"This leaf specifies the name of the syslog
message signer.";
}
container cert {
uses ks:private-key-grouping;
uses ks:certificate-grouping;
description
"This is the certificate that is periodically
sent to the remote receiver. Selection of the
certificate also implicitly selects the private
key used to sign the syslog messages.";
}
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 RFC 5426 is used.).";
}
leaf sig-resend-delay {
type uint32;
units "seconds";
default 5;
description
"This leaf specifies when to send the next
Signature Block transmission based on time. If
this many seconds have elapsed since the previous
sending of this Signature Block, resend it.";
}
leaf sig-resend-count {
type uint32;
default 0;
description
"This leaf specifies when to send the next
Signature Block transmission based on a count.
If this many other syslog messages have been
sent since the previous sending of this
Signature Block, resend it. A value of 0 means
that you don't resend based on the number of
messages.";
}
}
}
}
}
}
}
}
<CODE ENDS>
Below are ietf-syslog examples.¶
Requirement: Enable console logging of syslogs of severity critical¶
<syslog xmlns="urn:ietf:params:xml:ns:yang:ietf-syslog">
<actions>
<console>
<facility-filter>
<facility-list>
<facility>all</facility>
<severity>critical</severity>
</facility-list>
</facility-filter>
</console>
</actions>
</syslog>
¶
Enable remote logging of syslogs to udp destination foo.example.com for facility auth, severity error¶
<syslog xmlns="urn:ietf:params:xml:ns:yang:ietf-syslog">
<actions>
<remote>
<destination>
<name>remote1</name>
<udp>
<address>foo.example.com</address>
</udp>
<facility-filter>
<facility-list>
<facility>auth</facility>
<severity>error</severity>
</facility-list>
</facility-filter>
</destination>
</remote>
</actions>
</syslog>
¶
The authors wish to thank the following who commented on this proposal:¶
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.¶
This document registers one URI in the IETF XML registry [RFC3688]. Following the format in [RFC3688], the following registration is requested:¶
This document registers one YANG module in the YANG Module Names registry [RFC7895]. Following the format in [RFC7950], the following registration is requested:¶
The YANG module defined in this document is designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.¶
The NETCONF access control model (NACM) [RFC6536] provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content.¶
There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). 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.¶
In addition there are data nodes that require careful analysis and review. These are the subtrees and data nodes and their sensitivity/vulnerability:¶
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:¶
There are no RPC operations defined in this YANG module.¶
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 such facilities apply for local syslog-like logging functionality.¶
The following is an example that shows how additional facilities could be added to the list of available facilities (in this example two facilities are added):¶
module example-vendor-syslog-types {
namespace "http://example.com/ns/vendor-syslog-types";
prefix vendor-syslogtypes;
import ietf-syslog {
prefix syslogtypes;
}
organization "Example, Inc.";
contact
"Example, Inc.
Customer Service
E-mail: syslog-yang@example.com";
description
"This module contains a collection of vendor-specific YANG type
definitions for SYSLOG.";
revision 2017-08-11 {
description
"Version 1.0";
reference
"Vendor SYSLOG Types: SYSLOG YANG Model";
}
identity vendor_specific_type_1 {
base syslogtypes:syslog-facility;
description
"Adding vendor specific type 1 to syslog-facility";
}
identity vendor_specific_type_2 {
base syslogtypes:syslog-facility;
description
"Adding vendor specific type 2 to syslog-facility";
}
}
¶
Terminal output with requirements more complex than the console subtree currently provides, are expected to be supported via vendor extensions rather than handled via the file subtree.¶
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.¶
When an active syslog file with a name specified by log-file/name, reaches log-file/max-file-size and/or syslog events arrive after the period specified by log-file/rollover, the logging system can close the file, can compress it, and can name the archive file <log-file/name>.0.gz. The logging system can then open a new active syslog file <log-file/name>.¶
When the new syslog file reaches either of the size limits referenced above, <log-file/name>.0.gz can be renamed <log-file/name>.1.gz and the new syslog file can be closed, compressed and renamed <log-file/name>.0.gz. Each time that a new syslog file is closed, each of the prior syslog archive files named <log-file/name>.<n>.gz can be renamed to <log-file/name>.<n + 1>.gz.¶
Removal of archive log files could occur when either or 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.¶
- 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.¶