Internet DRAFT - draft-ietf-netmod-syslog-model
draft-ietf-netmod-syslog-model
NETMOD WG J. Clarke, Ed.
Internet-Draft Cisco
Intended status: Standards Track M. Jethanandani, Ed.
Expires: 7 September 2023 Kloud Services
C. Wildes, Ed.
Cisco Systems Inc.
K. Koushik, Ed.
Verizon Wireless
6 March 2023
A YANG Data Model for Syslog Configuration
draft-ietf-netmod-syslog-model-30
Abstract
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.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 7 September 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. NDMA Compliance . . . . . . . . . . . . . . . . . . . . . . . 3
4. Editorial Note (To be removed by RFC Editor) . . . . . . . . 4
5. Design of the Syslog Model . . . . . . . . . . . . . . . . . 4
5.1. Syslog Module . . . . . . . . . . . . . . . . . . . . . . 6
6. Syslog YANG Module . . . . . . . . . . . . . . . . . . . . . 14
6.1. The ietf-syslog Module . . . . . . . . . . . . . . . . . 14
7. Usage Examples . . . . . . . . . . . . . . . . . . . . . . . 34
7.1. Syslog Configuration for Severity Critical . . . . . . . 34
7.2. Remote Syslog Configuration . . . . . . . . . . . . . . . 34
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 35
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35
9.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 35
9.2. The YANG Module Names Registry . . . . . . . . . . . . . 36
10. Security Considerations . . . . . . . . . . . . . . . . . . . 36
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 37
11.1. Normative References . . . . . . . . . . . . . . . . . . 37
11.2. Informative References . . . . . . . . . . . . . . . . . 38
Appendix A. Implementer Guidelines . . . . . . . . . . . . . . . 39
A.1. Extending Facilities . . . . . . . . . . . . . . . . . . 39
A.2. Syslog Terminal Output . . . . . . . . . . . . . . . . . 40
A.3. Syslog File Naming Convention . . . . . . . . . . . . . . 41
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41
1. Introduction
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.
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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 [RFC8342].
1.1. Requirements Language
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.
2. Terminology
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.
3. NDMA Compliance
The YANG model in this document conforms to the Network Management
Datastore Architecture defined in [RFC8342] .
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4. Editorial Note (To be removed by RFC Editor)
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:
* I-D.ietf-netconf-crypto-types --> the assigned RFC value for
draft-ietf-netconf-crypto-types
* I-D.ietf-netconf-tls-client-server --> the assigned RFC value for
draft-ietf-netconf-tls-client-server
* zzzz --> the assigned RFC value for this draft
5. Design of the Syslog Model
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.
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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) |
+----------+ +----------+ +----------------+
Figure 1. Syslog Processing Flow
Collectors are configured using the leaves in the syslog model
"actions" container which correspond to each message collector:
console
log file(s)
remote relay(s)/collector(s)
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:
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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)
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, block the message, or stop 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).
5.1. Syslog Module
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? identityref
| +--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
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| | +--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 address? inet:host
| | +--rw port? inet:port-number
| +--:(tls)
| +--rw tls
| +--rw address? inet:host
| +--rw port?
| | inet:port-number
| +--rw client-identity!
| | +--rw (auth-type)
| | +--:(certificate)
| | | {client-ident-x509-cert}?
| | | +--rw certificate
| | | +--rw (local-or-keystore)
| | | +--:(local)
| | | | {local-definitions-suppo
rted,asymmetric-keys}?
| | | | +--rw local-definition
| | | | +--rw public-key-format
| | | | | identityref
| | | | +--rw public-key
| | | | | binary
| | | | +--rw private-key-format?
| | | | | identityref
| | | | +--rw (private-key-type)
| | | | | +--:(cleartext-private-k
ey)
| | | | | | +--rw cleartext-priva
te-key?
| | | | | | binary
| | | | | +--:(hidden-private-key)
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| | | | | | {hidden-keys}?
| | | | | | +--rw hidden-private-
key?
| | | | | | empty
| | | | | +--:(encrypted-private-k
ey)
| | | | | {private-key-en
cryption}?
| | | | | +--rw encrypted-priva
te-key
| | | | | +--rw encrypted-by
| | | | | +--rw encrypted-va
lue-format
| | | | | | identityre
f
| | | | | +--rw encrypted-va
lue
| | | | | binary
| | | | +--rw cert-data?
| | | | | end-entity-cert-cms
| | | | +---n certificate-expiratio
n
| | | | | {certificate-expira
tion-notification}?
| | | | | +-- expiration-date
| | | | | yang:date-and-ti
me
| | | | +---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
| | | +--:(keystore)
| | | {central-keystore-suppor
ted,asymmetric-keys}?
| | | +--rw keystore-reference
| | | +--rw asymmetric-key?
| | | | ks:asymmetric-key-r
ef
| | | | {central-keystore-s
upported,asymmetric-keys}?
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| | | +--rw certificate?
| | | leafref
| | +--:(raw-public-key)
| | | {client-ident-raw-public-key}?
| | | +--rw raw-private-key
| | | +--rw (local-or-keystore)
| | | +--:(local)
| | | | {local-definitions-suppo
rted,asymmetric-keys}?
| | | | +--rw local-definition
| | | | +--rw public-key-format
| | | | | identityref
| | | | +--rw public-key
| | | | | binary
| | | | +--rw private-key-format?
| | | | | identityref
| | | | +--rw (private-key-type)
| | | | +--:(cleartext-private-k
ey)
| | | | | +--rw cleartext-priva
te-key?
| | | | | binary
| | | | +--:(hidden-private-key)
| | | | | {hidden-keys}?
| | | | | +--rw hidden-private-
key?
| | | | | empty
| | | | +--:(encrypted-private-k
ey)
| | | | {private-key-en
cryption}?
| | | | +--rw encrypted-priva
te-key
| | | | +--rw encrypted-by
| | | | +--rw encrypted-va
lue-format
| | | | | identityre
f
| | | | +--rw encrypted-va
lue
| | | | binary
| | | +--:(keystore)
| | | {central-keystore-suppor
ted,asymmetric-keys}?
| | | +--rw keystore-reference?
| | | ks:asymmetric-key-ref
| | +--:(tls12-psk)
| | | {client-ident-tls12-psk}?
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| | | +--rw tls12-psk
| | | +--rw (local-or-keystore)
| | | | +--:(local)
| | | | | {local-definitions-suppo
rted,symmetric-keys}?
| | | | | +--rw local-definition
| | | | | +--rw key-format?
| | | | | | identityref
| | | | | +--rw (key-type)
| | | | | +--:(cleartext-key)
| | | | | | +--rw cleartext-key?
| | | | | | binary
| | | | | +--:(hidden-key)
| | | | | | {hidden-keys}?
| | | | | | +--rw hidden-key?
| | | | | | empty
| | | | | +--:(encrypted-key)
| | | | | {symmetric-key-
encryption}?
| | | | | +--rw encrypted-key
| | | | | +--rw encrypted-by
| | | | | +--rw encrypted-va
lue-format
| | | | | | identityre
f
| | | | | +--rw encrypted-va
lue
| | | | | binary
| | | | +--:(keystore)
| | | | {central-keystore-suppor
ted,symmetric-keys}?
| | | | +--rw keystore-reference?
| | | | ks:symmetric-key-ref
| | | +--rw id?
| | | string
| | +--:(tls13-epsk)
| | {client-ident-tls13-epsk}?
| | +--rw tls13-epsk
| | +--rw (local-or-keystore)
| | | +--:(local)
| | | | {local-definitions-suppo
rted,symmetric-keys}?
| | | | +--rw local-definition
| | | | +--rw key-format?
| | | | | identityref
| | | | +--rw (key-type)
| | | | +--:(cleartext-key)
| | | | | +--rw cleartext-key?
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| | | | | binary
| | | | +--:(hidden-key)
| | | | | {hidden-keys}?
| | | | | +--rw hidden-key?
| | | | | empty
| | | | +--:(encrypted-key)
| | | | {symmetric-key-
encryption}?
| | | | +--rw encrypted-key
| | | | +--rw encrypted-by
| | | | +--rw encrypted-va
lue-format
| | | | | identityre
f
| | | | +--rw encrypted-va
lue
| | | | binary
| | | +--:(keystore)
| | | {central-keystore-suppor
ted,symmetric-keys}?
| | | +--rw keystore-reference?
| | | ks:symmetric-key-ref
| | +--rw external-identity
| | | string
| | +--rw hash
| | | tlscmn:epsk-supported-hash
| | +--rw context?
| | | string
| | +--rw target-protocol?
| | | uint16
| | +--rw target-kdf?
| | uint16
| +--rw server-authentication
| | +--rw ca-certs! {server-auth-x509-cert}?
| | | +--rw (local-or-truststore)
| | | +--:(local)
| | | | {local-definitions-supported}?
| | | | +--rw local-definition
| | | | +--rw certificate* [name]
| | | | +--rw name
| | | | | string
| | | | +--rw cert-data
| | | | | trust-anchor-cert-cms
| | | | +---n certificate-expiration
| | | | {certificate-expiratio
n-notification}?
| | | | +-- expiration-date
| | | | yang:date-and-time
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| | | +--:(truststore)
| | | {central-truststore-supported,
certificates}?
| | | +--rw truststore-reference?
| | | ts:certificate-bag-ref
| | +--rw ee-certs! {server-auth-x509-cert}?
| | | +--rw (local-or-truststore)
| | | +--:(local)
| | | | {local-definitions-supported}?
| | | | +--rw local-definition
| | | | +--rw certificate* [name]
| | | | +--rw name
| | | | | string
| | | | +--rw cert-data
| | | | | trust-anchor-cert-cms
| | | | +---n certificate-expiration
| | | | {certificate-expiratio
n-notification}?
| | | | +-- expiration-date
| | | | yang:date-and-time
| | | +--:(truststore)
| | | {central-truststore-supported,
certificates}?
| | | +--rw truststore-reference?
| | | ts:certificate-bag-ref
| | +--rw raw-public-keys!
| | | {server-auth-raw-public-key}?
| | | +--rw (local-or-truststore)
| | | +--:(local)
| | | | {local-definitions-supported}?
| | | | +--rw local-definition
| | | | +--rw public-key* [name]
| | | | +--rw name
| | | | | string
| | | | +--rw public-key-format
| | | | | identityref
| | | | +--rw public-key
| | | | binary
| | | +--:(truststore)
| | | {central-truststore-supported,
public-keys}?
| | | +--rw truststore-reference?
| | | ts:public-key-bag-ref
| | +--rw tls12-psks? empty
| | | {server-auth-tls12-psk}?
| | +--rw tls13-epsks? empty
| | {server-auth-tls13-epsk}?
| +--rw hello-params {tlscmn:hello-params}?
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| | +--rw tls-versions
| | | +--rw tls-version* identityref
| | +--rw cipher-suites
| | +--rw cipher-suite* identityref
| +--rw keepalives {tls-client-keepalives}?
| +--rw peer-allowed-to-send? empty
| +--rw test-peer-aliveness!
| +--rw max-wait? uint16
| +--rw max-attempts? uint8
+--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? 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)
| | | | +--rw cleartext-private-key? binary
| | | +--:(hidden-private-key) {hidden-keys}?
| | | | +--rw hidden-private-key? empty
| | | +--:(encrypted-private-key)
| | | {private-key-encryption}?
| | | +--rw encrypted-private-key
| | | +--rw encrypted-by
| | | +--rw encrypted-value-format
| | | | identityref
| | | +--rw encrypted-value
| | | binary
| | +--rw cert-data?
| | | end-entity-cert-cms
| | +---n certificate-expiration
| | | {certificate-expiration-notification}
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?
| | | +-- 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
Figure 1: Tree Diagram for Syslog Model
6. Syslog YANG Module
6.1. The ietf-syslog Module
This module imports typedefs from [RFC6991] , [RFC8343] , groupings
from [I-D.ietf-netconf-crypto-types] , and
[I-D.ietf-netconf-tls-client-server] , and it references [RFC5424] ,
[RFC5425] ,[RFC5426] , and [RFC5848] ,[RFC8089] , [RFC8174] , and
[Std-1003.1-2008] .
<CODE BEGINS> file "ietf-syslog@2023-03-06.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
"RFC 8343: A YANG Data Model for Interface Management";
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}
import ietf-tls-client {
prefix tlsc;
reference
"I-D.ietf-netconf-tls-client-server:
YANG Groupings for TLS Clients and TLS Servers";
}
import ietf-crypto-types {
prefix ct;
reference
"I-D.ietf-netconf-crypto-types: YANG Data Types 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) 2023 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);
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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 2023-03-06 {
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
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"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.";
}
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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
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"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;
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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";
}
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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";
}
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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";
}
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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 the message will be logged.";
}
identity block {
base action;
description
"This identity specifies that if the compare operation is
true the message will not be logged.";
}
identity stop {
base action;
description
"This identity specifies that if the compare operation is
true the message will not be logged and no further
processing will occur for it.";
}
grouping severity-filter {
description
"This grouping defines the processing used to select
log messages by comparing syslog message severity using
the following processing rules:
- if 'none', do not match.
- if 'all', match.
- else compare message severity with the specified
severity according to the default compare rule (all
messages of the specified severity and greater match)
or if the select-adv-compare feature is present, use
the advance-compare rule.";
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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
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message severity with the specified severity.";
}
leaf action {
type identityref {
base "action";
}
default "log";
description
"The action can be used to specify how the message
should be handled. This may include logging the
message, not logging the message (i.e., blocking
it), or stopping further processing.";
}
description
"This container describes additional severity compare
operations that can be used in place of the default
severity comparison. The compare leaf specifies the
type of 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;
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}
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";
}
}
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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
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"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
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"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.";
}
}
}
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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
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used to send messages to the remote syslog
server. If not set, messages can be sent
on any interface.";
}
container signing {
if-feature "signed-messages";
presence
"If present, syslog-signing options is
activated.";
description
"This container describes the configuration
parameters for signed syslog messages.";
reference
"RFC 5848: Signed Syslog Messages";
container cert-signers {
description
"This container describes the signing
certificate configuration for
Signature Group 0 which covers the
case for administrators who want all
Signature Blocks to be sent to a
single destination.";
list cert-signer {
key "name";
description
"This list describes a collection
of syslog message signers.";
leaf name {
type string;
description
"This leaf specifies the name
of the syslog message
signer.";
}
container cert {
uses ct:asymmetric-key-pair-with-cert-grouping;
description
"This is the certificate that
is periodically sent to the
remote receiver. The
certificate is inherently
associated with its private
and public keys.";
}
leaf hash-algorithm {
type enumeration {
enum SHA1 {
value 1;
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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";
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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.";
}
}
}
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}
}
}
}
}
<CODE ENDS>
Figure 2: Sylog YANG Model
7. Usage Examples
7.1. Syslog Configuration for Severity Critical
[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>
<facility-filter>
<facility-list>
<facility>all</facility>
<severity>critical</severity>
</facility-list>
</facility-filter>
</console>
</actions>
</syslog>
Figure 3: Syslog Configuration for Severity Critical
7.2. Remote Syslog Configuration
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[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>
<address>foo.example.com</address>
</udp>
<facility-filter>
<facility-list>
<facility>auth</facility>
<severity>error</severity>
</facility-list>
</facility-filter>
</destination>
</remote>
</actions>
</syslog>
Figure 4: Remote Syslog Configuration
8. Acknowledgements
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.
9. IANA Considerations
9.1. The IETF XML Registry
This document registers one URI in the IETF XML registry [RFC3688] .
Following the format in [RFC3688] , the following registration is
requested:
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URI: urn:ietf:params:xml:ns:yang:ietf-syslog
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
9.2. The YANG Module Names Registry
This document registers one YANG module in the YANG Module Names
registry [RFC8525] . Following the format in [RFC7950] , the
following registration is requested:
name: ietf-syslog
namespace: urn:ietf:params:xml:ns:yang:ietf-syslog
prefix: ietf-syslog
reference: RFC zzzz
10. Security Considerations
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) [RFC8341] 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:
facility-filter/pattern-match: When writing this node,
implementations MUST ensure that the regular expression pattern
match is not constructed to cause a regular expression denial
of service attack due to a pattern that causes the regular
expression implementation to work very slowly (exponentially
related to input size).
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remote/destination/signing/cert-signer: When writing this subtree,
implementations MUST NOT specify a private key that is used for
any other purpose.
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:
remote/destination/transport: This subtree contains information
about other hosts in the network, and the TLS transport
certificate properties if TLS is selected as the transport
protocol.
remote/destination/signing: This subtree contains information about
the syslog message signing properties including signing
certificate information.
There are no RPC operations defined in this YANG module.
11. References
11.1. Normative References
[I-D.ietf-netconf-crypto-types]
Watsen, K., "YANG Data Types and Groupings for
Cryptography", Work in Progress, Internet-Draft, draft-
ietf-netconf-crypto-types-26, 12 December 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
crypto-types-26>.
[I-D.ietf-netconf-tls-client-server]
Watsen, K., "YANG Groupings for TLS Clients and TLS
Servers", Work in Progress, Internet-Draft, draft-ietf-
netconf-tls-client-server-32, 12 December 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
tls-client-server-32>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5424] Gerhards, R., "The Syslog Protocol", RFC 5424,
DOI 10.17487/RFC5424, March 2009,
<https://www.rfc-editor.org/info/rfc5424>.
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[RFC5425] Miao, F., Ed., Ma, Y., Ed., and J. Salowey, Ed.,
"Transport Layer Security (TLS) Transport Mapping for
Syslog", RFC 5425, DOI 10.17487/RFC5425, March 2009,
<https://www.rfc-editor.org/info/rfc5425>.
[RFC5426] Okmianski, A., "Transmission of Syslog Messages over UDP",
RFC 5426, DOI 10.17487/RFC5426, March 2009,
<https://www.rfc-editor.org/info/rfc5426>.
[RFC5848] Kelsey, J., Callas, J., and A. Clemm, "Signed Syslog
Messages", RFC 5848, DOI 10.17487/RFC5848, May 2010,
<https://www.rfc-editor.org/info/rfc5848>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8089] Kerwin, M., "The "file" URI Scheme", RFC 8089,
DOI 10.17487/RFC8089, February 2017,
<https://www.rfc-editor.org/info/rfc8089>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
<https://www.rfc-editor.org/info/rfc8343>.
[RFC8525] Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
and R. Wilton, "YANG Library", RFC 8525,
DOI 10.17487/RFC8525, March 2019,
<https://www.rfc-editor.org/info/rfc8525>.
[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/>.
11.2. Informative References
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[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
Appendix A. Implementer Guidelines
A.1. Extending Facilities
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):
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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";
}
}
A.2. Syslog Terminal Output
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.
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A.3. Syslog File Naming Convention
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.
Authors' Addresses
Joe Clarke (editor)
Cisco
United States of America
Email: jclarke@cisco.com
Mahesh Jethanandani (editor)
Kloud Services
United States of America
Email: mjethanandani@gmail.com
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Clyde Wildes (editor)
Cisco Systems Inc.
170 West Tasman Drive
San Jose, CA 95134
United States of America
Phone: +1 415 819-6111
Email: clyde@clydewildes.com
Kiran Koushik (editor)
Verizon Wireless
500 W Dove Rd.
Southlake, TX 76092
United States of America
Phone: +1 512 650-0210
Email: kirankoushik.agraharasreenivasa@verizonwireless.com
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