RFC 5427 PROPOSED STANDARD SYSLOG · SNMP · MIB
Syslog TCs: Textual Conventions for Syslog Management
Standard names and numbers for syslog Facility and Severity, ready for reuse in MIB modules.
RFC EDITOR
Keeni, G., "Textual Conventions for Syslog Management", RFC 5427, DOI 10.17487/RFC5427, March 2009, <https://www.rfc-editor.org/info/rfc5427>.
BIBTEX
@misc{rfc5427,
series = {Request for Comments},
number = 5427,
howpublished = {RFC 5427},
publisher = {RFC Editor},
doi = {10.17487/RFC5427},
url = {https://www.rfc-editor.org/info/rfc5427},
author = {G. Keeni},
title = {{Textual Conventions for Syslog Management}},
pagetotal = 8,
year = 2009,
month = mar,
} RFC text
Contents
Network Working Group G. Keeni
Request for Comments: 5427 Cyber Solutions Inc.
Category: Standards Track March 2009
Textual Conventions for Syslog Management
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (c) 2009 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 in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
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material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Abstract
This MIB module defines textual conventions to represent Facility and
Severity information commonly used in syslog messages. The intent is
that these textual conventions will be imported and used in MIB
modules that would otherwise define their own representations.
Table of Contents
1. The Internet-Standard Management Framework ......................2
2. Background ......................................................2
3. The Syslog Textual Conventions MIB ..............................3
4. Security Considerations .........................................7
5. IANA Considerations .............................................7
6. References ......................................................8
6.1. Normative References .......................................8
6.2. Informative References .....................................8
7. Acknowledgments .................................................8
1. The Internet-Standard Management Framework
For a detailed overview of the documents that describe the current
Internet-Standard Management Framework, please refer to section 7 of
RFC 3410 [RFC3410].
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. MIB objects are generally
accessed through the Simple Network Management Protocol (SNMP).
Objects in the MIB are defined using the mechanisms defined in the
Structure of Management Information (SMI). This memo specifies a MIB
module that is compliant to the SMIv2, which is described in STD 58,
RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
[RFC2580].
2. Background
Operating systems, processes, and applications, collectively termed
"Facilities" in the following, generate messages indicating their own
status or the occurrence of events. These messages have come to be
known as syslog messages. A syslog message in general will contain
among other things a code representing the Facility that generated
the message and a code representing the Severity of the message. The
Facility and the Severity codes are commonly used to categorize and
select received syslog messages for processing and display. The
Facility codes have been useful in qualifying the originator of the
content of the messages but in some cases they are not specific
enough to explicitly identify the originator. Implementations of the
syslog protocol [RFC5424] that contain structured data elements
(SDEs) should use these SDEs to clarify the entity that originated
the content of the message.
This document defines a set of textual conventions (TCs) that can be
used to represent Facility and Severity codes commonly used in syslog
messages.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
3. The Syslog Textual Conventions MIB
SYSLOG-TC-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, mib-2
FROM SNMPv2-SMI -- [RFC2578]
TEXTUAL-CONVENTION
FROM SNMPv2-TC; -- [RFC2579]
syslogTCMIB MODULE-IDENTITY
LAST-UPDATED "200903300000Z" -- 30 March 2009
ORGANIZATION "IETF Syslog Working Group"
CONTACT-INFO
" Glenn Mansfield Keeni
Postal: Cyber Solutions Inc.
6-6-3, Minami Yoshinari
Aoba-ku, Sendai, Japan 989-3204.
Tel: +81-22-303-4012
Fax: +81-22-303-4015
EMail: glenn@cysols.com
Support Group EMail: syslog@ietf.org
"
DESCRIPTION
"The MIB module containing textual conventions for syslog
messages.
Copyright (c) 2009 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, are permitted provided that the
following conditions are met:
- Redistributions of source code must retain the above
copyright notice, this list of conditions and the
following disclaimer.
- Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the
following disclaimer in the documentation and/or other
materials provided with the distribution.
- Neither the name of Internet Society, IETF or IETF
Trust, nor the names of specific contributors, may be
used to endorse or promote products derived from this
software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS 'AS IS' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
This version of this MIB module is part of RFC 5427;
see the RFC itself for full legal notices.
"
REVISION "200903300000Z" -- 30 March 2009
DESCRIPTION
"The initial version, published as RFC 5427."
::= { mib-2 173 }
-- -------------------------------------------------------------
-- Textual Conventions
-- -------------------------------------------------------------
SyslogFacility ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"This textual convention enumerates the Facilities that
originate syslog messages.
The Facilities of syslog messages are numerically coded
with decimal values. For interoperability and backwards-
compatibility reasons, this document specifies a
normative mapping between a label, which represents a
Facility, and the corresponding numeric value. This label
could be used in, for example, SNMP Manager user
interfaces.
The label itself is often semantically meaningless
because it is impractical to attempt to enumerate all
possible Facilities, and many daemons and processes do
not have an explicitly assigned Facility code or label.
For example, there is no Facility label corresponding to
an HTTP service. An HTTP service implementation might log
messages as coming from, for example, 'local7' or 'uucp'.
This is typical current practice, and originators, relays,
and collectors can be configured to properly handle this
situation. For improved accuracy, an application can also
include an APP-NAME structured data element.
Note that operating system mechanisms for configuring
syslog, such as syslog.conf, have not yet been standardized
and might use different sets of Facility labels and/or
mapping between Facility labels and Facility codes than the
MIB.
In particular, the labels corresponding to Facility codes 4,
10, 13, and 14, and the code corresponding to the Facility
label 'cron' are known to vary across different operating
systems. To distinguish between the labels corresponding
to Facility codes 9 and 15, a label of 'cron2' is assigned
to the Facility code 15. This list is not intended to be
exhaustive; other differences might exist, and new
differences might be introduced in the future.
The mapping specified here MUST be used in a MIB network
management interface, even though a particular syslog
implementation might use a different mapping in a
different network management interface.
"
REFERENCE "The Syslog Protocol (RFC5424): Table 1"
SYNTAX INTEGER
{
kern (0), -- kernel messages
user (1), -- user-level messages
mail (2), -- mail system messages
daemon (3), -- system daemons' messages
auth (4), -- authorization messages
syslog (5), -- messages generated internally by
-- syslogd
lpr (6), -- line printer subsystem messages
news (7), -- network news subsystem messages
uucp (8), -- UUCP subsystem messages
cron (9), -- clock daemon messages
authpriv (10),-- security/authorization messages
ftp (11),-- ftp daemon messages
ntp (12),-- NTP subsystem messages
audit (13),-- audit messages
console (14),-- console messages
cron2 (15),-- clock daemon messages
local0 (16),
local1 (17),
local2 (18),
local3 (19),
local4 (20),
local5 (21),
local6 (22),
local7 (23)
}
SyslogSeverity ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"This textual convention enumerates the Severity levels
of syslog messages.
The Severity levels of syslog messages are numerically
coded with decimal values. For interoperability and
backwards-compatibility reasons, this document specifies
a normative mapping between a label, which represents a
Severity level, and the corresponding numeric value.
This label could be used in, for example, SNMP Manager
user interfaces.
The label itself is often semantically meaningless
because it is impractical to attempt to strictly define
the criteria for each Severity level, and the criteria
that is used by syslog originators is, and has
historically been, implementation-dependent.
Note that operating system mechanisms for configuring
syslog, such as syslog.conf, have not yet been standardized
and might use different sets of Severity labels and/or
mapping between Severity labels and Severity codes than the
MIB.
For example, the foobar application might log messages as
'crit' based on some subjective criteria. Yet the operator
can configure syslog to forward these messages, even though
the criteria for 'crit' may differ from one originator to
another. This is typical current practice, and originators,
relays, and collectors can be configured to properly handle
this situation.
"
REFERENCE "The Syslog Protocol (RFC5424): Table 2"
SYNTAX INTEGER
{
emerg (0), -- emergency; system is unusable
alert (1), -- action must be taken immediately
crit (2), -- critical condition
err (3), -- error condition
warning (4), -- warning condition
notice (5), -- normal but significant condition
info (6), -- informational message
debug (7) -- debug-level messages
}
END
4. Security Considerations
This module does not define any management objects. Instead, it
defines a set of textual conventions which may be used by other MIB
modules to define management objects. Meaningful security
considerations can only be written in the MIB modules that define
management objects. This document has therefore no impact on the
security of the Internet. Since objects defined using the TCs
defined in this document may introduce security issues, the user of
these TCs should read the security considerations section of
[RFC5424].
5. IANA Considerations
The MIB modules in this document use the following IANA-assigned
OBJECT IDENTIFIER values recorded in the SMI Numbers registry:
Descriptor OBJECT IDENTIFIER value
---------- -----------------------
syslogTCMIB { mib-2 173 }
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Structure of Management Information Version 2 (SMIv2)",
STD 58, RFC 2578, April 1999.
[RFC2579] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Textual Conventions for SMIv2", STD 58, RFC 2579, April
1999.
[RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Conformance Statements for SMIv2", STD 58, RFC 2580,
April 1999.
[RFC5424] Gerhards, R., "The Syslog Protocol", RFC 5424, March 2009.
6.2. Informative References
[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002.
7. Acknowledgments
This document is a product of the Syslog Working Group. The author
would like to thank Chris Lonvick, David Harrington, Juergen
Schoenwaelder, and Pasi Eronen for their comments and suggestions.
Author's Address
Glenn Mansfield Keeni
Cyber Solutions Inc.
6-6-3 Minami Yoshinari
Aoba-ku, Sendai 989-3204
Japan
Phone: +81-22-303-4012
EMail: glenn@cysols.com
AI ELI5
On this page
PROBLEMMany MIB modules that deal with syslog messages would otherwise each define their own way to represent the Facility and Severity of a message.
MECHANISMThis MIB module defines two textual conventions, SyslogFacility and SyslogSeverity, that map labels to the numeric codes used in syslog messages.
WHY IT MATTERSOther MIB modules can import these conventions, and the mapping MUST be used in a MIB network management interface.
§2Background
Operating systems, processes and applications, collectively called Facilities, generate messages about their status or events. These are known as syslog messages. A message generally carries a code for the Facility that generated it and a code for its Severity, and both are commonly used to categorize and select received messages.
Facility codes do not always identify the originator precisely. Implementations of the syslog protocol (RFC 5424) that contain structured data elements (SDEs) should use them to clarify the originating entity. This document defines textual conventions (TCs) for Facility and Severity codes.
Programs write notes about what they are doing. Each note says who wrote it and how important it is, and this memo gives those labels standard names.
§1The Management Framework
Managed objects live in a virtual information store called the Management Information Base (MIB), generally accessed through SNMP. Objects are defined using the Structure of Management Information (SMI). This memo specifies a MIB module compliant with SMIv2, described in RFC 2578, RFC 2579 and RFC 2580. The overview of the framework is in section 7 of RFC 3410.
Network gear keeps its facts in a big shared notebook with strict rules about how entries are written. This memo follows those rules.
§3SyslogFacility
The SyslogFacility convention is an integer enumeration of 24 Facilities, numbered 0 to 23, for example kern (0), user (1), mail (2), daemon (3) and local0 (16) through local7 (23). For interoperability and backwards compatibility, the mapping between label and number is normative, and it MUST be used in a MIB network management interface even if a syslog implementation uses a different mapping elsewhere.
The labels are often semantically weak. There is, for example, no Facility label for an HTTP service, which might log as local7 or uucp. The labels for codes 4, 10, 13 and 14, and the code for the label cron, are known to vary across operating systems. To tell codes 9 and 15 apart, code 15 is labelled cron2.
There is a numbered list of 24 senders, like a class roll call. Some systems call a few of them by different names, so the memo says which name goes with which number.
§4SyslogSeverity
The SyslogSeverity convention enumerates eight levels, from emerg (0) to debug (7). Like Facilities, the label-to-number mapping is normative for interoperability.
The RFC notes that the label is often semantically meaningless, because the criteria syslog originators use for each level are implementation-dependent and have historically been so. An application might log messages as crit on subjective criteria, and operators can still configure syslog to forward them.
Severity is a scale from "everything is on fire" to "just chatting". The memo gives each step a number and a name.
- 0emerg — Emergency; system is unusable.
- 1alert — Action must be taken immediately.
- 2crit — Critical condition.
- 3err — Error condition.
- 4warning — Warning condition.
- 5notice — Normal but significant condition.
- 6info — Informational message.
- 7debug — Debug-level messages.
§5Security and IANA
The module defines no management objects, only conventions that other MIB modules may use, so the RFC says it has no impact on the security of the Internet. Users of these conventions should read the security considerations of RFC 5424, since objects built with them may introduce security issues.
IANA recorded syslogTCMIB as { mib-2 173 } in the SMI Numbers registry.
This memo only makes labels, not anything that can be attacked. Whoever uses the labels has to think about safety in their own work.
§6References
[RFC5424]RFC 5424Gerhards, R., "The Syslog Protocol", RFC 5424, March 2009.March 2009[RFC2578]RFC 2578McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.April 1999[RFC2579]RFC 2579McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999.April 1999[RFC2580]RFC 2580McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Conformance Statements for SMIv2", STD 58, RFC 2580, April 1999.April 1999[RFC3410]RFC 3410Case, J., et al., "Introduction and Applicability Statements for Internet-Standard Management Framework", RFC 3410, December 2002.December 2002