Network Working Group D. New
Internet-Draft M.T. Rose
Expires: May 14, 2001 Invisible Worlds, Inc.
November 13, 2000
Reliable Delivery for syslog
draft-ietf-syslog-reliable-02
Status of this Memo
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Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
The syslog protocol[1] describes a number of service options related
to propagating event messages. This memo describes two mappings of
the syslog protocol to TCP connections, both useful for reliable
delivery of event messages. The first provides a trivial mapping
maximizing backward compatibility. The second provides a more
complete mapping. Both provide a degree of robustness and security
in message delivery that is unavailable to the usual UDP-based
syslog protocol, by providing encryption and authentication over a
connection-oriented protocol.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The Model . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. The RAW Profile . . . . . . . . . . . . . . . . . . . . . . 6
3.1 RAW Profile Overview . . . . . . . . . . . . . . . . . . . . 6
3.2 RAW Profile Identification and Initialization . . . . . . . 8
3.3 RAW Profile Message Syntax . . . . . . . . . . . . . . . . . 8
3.4 RAW Profile Semantics . . . . . . . . . . . . . . . . . . . 9
4. The COOKED Profile . . . . . . . . . . . . . . . . . . . . . 10
4.1 COOKED Profile Overview . . . . . . . . . . . . . . . . . . 10
4.2 COOKED Profile Identification and Initialization . . . . . . 10
4.3 COOKED Profile Message Syntax . . . . . . . . . . . . . . . 10
4.4 COOKED Profile Message Semantics . . . . . . . . . . . . . . 11
4.4.1 The IAM Element . . . . . . . . . . . . . . . . . . . . . . 11
4.4.2 The ENTRY Element . . . . . . . . . . . . . . . . . . . . . 13
4.4.3 The RECEIVED Element . . . . . . . . . . . . . . . . . . . . 14
5. Additional Provisioning . . . . . . . . . . . . . . . . . . 17
5.1 Message Authenticity . . . . . . . . . . . . . . . . . . . . 17
5.2 Message Replay . . . . . . . . . . . . . . . . . . . . . . . 17
5.3 Message Integrity . . . . . . . . . . . . . . . . . . . . . 17
5.4 Message Observation . . . . . . . . . . . . . . . . . . . . 18
5.5 Summary of Recommended Practices . . . . . . . . . . . . . . 18
6. Initial Registrations . . . . . . . . . . . . . . . . . . . 19
6.1 Registration: The RAW Profile . . . . . . . . . . . . . . . 19
6.2 Registration: The COOKED Profile . . . . . . . . . . . . . . 19
7. The syslog DTD . . . . . . . . . . . . . . . . . . . . . . . 20
8. Reply Codes . . . . . . . . . . . . . . . . . . . . . . . . 23
9. Security Considerations . . . . . . . . . . . . . . . . . . 24
References . . . . . . . . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 25
A. History of Significant Changes . . . . . . . . . . . . . . . 27
A.1 Significant Changes Since syslog-reliable-00 . . . . . . . . 27
A.2 Significant Changes Since syslog-reliable-01 . . . . . . . . 27
B. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 28
Full Copyright Statement . . . . . . . . . . . . . . . . . . 29
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1. Introduction
The syslog protocol[1] presents a spectrum of service options for
provisioning an event-based logging service over a network. Each
option has associated benefits and costs. Accordingly, the choice as
to what combination of options is provisioned is both an engineering
and administrative decision. This memo describes how to realize the
syslog protocol when reliable delivery is selected as a required
service. It is beyond the scope of this memo to argue for, or
against, the use of reliable delivery for the syslog protocol.
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2. The Model
The syslog service supports three roles of operation: device, relay,
and collector.
Devices and collectors act as sources and sinks, respectively, of
syslog entries. In the simplest case, only a device and collector
are present. E.g.,
+--------+ +-----------+
| Device | -----> | Collector |
+--------+ +-----------+
The relationship between devices and collectors is potentially
many-to-many. I.e., a device might communicate with many collectors;
similarly, a collector might communicate with many devices.
A relay operates in both modes, accepting syslog entries from
devices and other relays and forwarding those entries to collectors
and other relays.
For example,
+--------+ +-------+ +-------+ +-----------+
| Device | ---> | Relay | -...-> | Relay | ---> | Collector |
+--------+ +-------+ +-------+ +-----------+
As shown, more than one relay may be present between any particular
device and collector.
A relay may be necessary for administrative reasons. For example, a
relay might run as an application proxy on a firewall. Also, there
might be one relay per company department, which authenticates all
the devices in the department, and which in turn authenticates
itself to a company-wide collector.
A relay can also serve to filter messages. For example, one relay
may collect the syslog information from an entire web server farm,
summarizing hit counts for report generation, forwarding "page not
found" messages (indicating a possible broken link) to a collector
that presents it to the webmaster, and sending more urgent messages
(such as hardware failure reports) to a collector that gateways them
to a pager. A relay may also be used to convert formats from a
device's output to a collector's input.
It should be noted that a role of device, relay, or collector is
relevant only to a particular BEEP channel (q.v., below). A single
server can serve as a device, a relay, and a collector, all at once,
if so configured. It can even serve as a relay and a collector to
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the same device at the same time using different BEEP channels over
the same connection-oriented session; this might be useful to
collect status yet relay urgent error messages.
To provide reliable delivery when realizing the syslog protocol,
this memo defines two BEEP profiles. BEEP[2] is a generic
application protocol framework for connection-oriented, asynchronous
interactions. Within BEEP, features such as authentication, privacy,
and reliability through retransmission are provided. There are two
profiles defined in this memo:
o The RAW profile is designed to provide a high-performance,
low-impact footprint, using essentially the same format as the
existing UDP-based syslog service.
o The COOKED profile is designed to provide a structured entry
format, in which individual entries are acknowledged (either
positively or negatively).
The choice of profile is independent of the operational roles
discussed above.
For example, in
+--------+ +-------+ +-----------+
| Device | -----> | Relay | -----> | Collector |
+--------+ +-------+ +-----------+
the device-to-relay link could be configured to use the RAW profile,
while the relay-to-collector link could be configured to use the
COOKED profile. (For example, the relay may be parsing the RAW
syslog messages from the device, knowing the details of their
formats, before passing them to a more generic collector.) Indeed,
the same device may use different profiles, depending on the
collector to which it is sending entries.
Devices and relays SHOULD discover relays and collectors via the DNS
SRV algorithm[6]. The service used is "syslog" and the protocol used
is "tcp". This allows for central administration of addressing,
fallback for failed relays and collectors, and static load
balancing.
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3. The RAW Profile
3.1 RAW Profile Overview
The RAW profile is designed for minimal implementation effort, high
efficiency, and backwards compatibility. It is appropriate
especially in cases where legacy syslog processing will be applied.
When the profile is started, no piggyback data is supplied. All BEEP
messages in the RAW profile are specified as having a MIME
Content-Type[5] of application/octet-stream. Once the channel is
open, the listener (not the initiator) sends a MSG message
indicating it is ready to act as a syslog sink. (Refer to [2]'s
Section 2.1 for a discussion of roles that a BEEP peer may perform,
including definitions of the terms "listener", "initiator",
"client", and "server".)
The initiator uses ANS replies to supply one or more syslog entries
in the current UDP format, as specified in [1]'s Section 3. When the
initiator has no more entries to send, it finishes with a NUL reply
and closes the channel.
An example might appear as follows:
L: <wait for incoming connection>
I: <establish connection>
L: RPY 0 0 . 0 165
L:
L: <greeting>
L: <profile
L: uri='http://xml.resource.org/profiles/syslog/COOKED' />
L: <profile uri='http://xml.resource.org/profiles/syslog/RAW' />
L: </greeting>
L: END
I: RPY 0 0 . 0 16
I:
I: <greeting />
I: END
I: MSG 0 1 . 16 121
I: Content-type: text/xml
I:
I: <start number='1'>
I: <profile uri='http://xml.resource.org/profiles/syslog/RAW' />
I: </start>
I: END
L: RPY 0 1 . 165 88
L: Content-type: text/xml
L:
L: <profile uri='http://xml.resource.org/profiles/syslog/RAW' />
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L: END
L: MSG 1 0 . 0 50
L:
L: Central Services. This has not been a recording.
L: END
I: ANS 1 0 . 0 61 0
I:
I: <29>Oct 27 13:21:08 ductwork imxpd[141]: Heating emergency.END
I: ANS 1 0 . 61 58 1
I:
I: <29>Oct 27 13:22:15 ductwork imxpd[141]: Contact Tuttle.END
I: NUL 1 0 . 119 0
I: END
L: MSG 0 3 . 253 58
L: Content-Type: text/xml
L:
L: <close number='1' code='200' />
L: END
I: RPY 0 3 . 137 34
I: Content-Type: text/xml
I:
I: <ok />
I: END
I: MSG 0 4 . 171 59
I: Content-Type: text/xml
I:
I: <close number='0' code='200' />
I: END
L: RPY 0 4 . 311 34
L: Content-type: text/xml
L:
L: <ok />
L: END
L: <closes connection>
I: <closes connection>
L: <awaits next connection>
Here we see a BEEP session established, followed by the use of the
RAW profile. The initiator is a device, while the listener is a
collector. The initiator opens the channel, but the listener sends
the first MSG. This allows the initiator to send any number of ANS
replies carrying syslog event messages. The initiator sends a NUL
reply to indicate it is finished. Upon receiving the NUL, the
listener closes the RAW channel. The initiator has the choice of
closing the entire BEEP session or opening a new syslog channel (RAW
or COOKED) for more transfers. In this example, the initiator
chooses to close the entire BEEP session.
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The overhead for one ANS frame is about thirty octets, once the
initial handshakes have been exchanged. If this overhead is too
high, then messages are likely being generated at a high rate. In
this case, multiple syslog messages can be aggregated into a single
ANS frame, each separated by a CRLF sequence from the preceding. The
final message still MUST NOT end with a CRLF.
For example,
L: MSG 1 0 . 0 50
L:
L: Central Services. This has not been a recording.
L: END
I: ANS 1 0 . 0 119 0
I:
I: <29>Oct 27 13:21:08 ductwork imxpd[141]: Heating emergency.
I: <29>Oct 27 13:21:09 ductwork imxpd[141]: Contact Tuttle.END
I: NUL 1 0 . 119 0
I: END
3.2 RAW Profile Identification and Initialization
The RAW syslog profile is identified as
http://xml.resource.org/profiles/syslog/RAW
in the BEEP "profile" element during channel creation.
No data is piggybacked during channel creation.
3.3 RAW Profile Message Syntax
All BEEP messages in this profile have a MIME content-type of
application/octet-stream. The listener's first BEEP message is
ignored and indeed may be empty except for headers; hence, any
syntax is acceptable.
The ANS replies the initiator sends in response MUST be formatted
according to Section 3 of [1]. In particular, the syslog message
starts with a leading "<" ('less-than' character), followed by a
number, which is followed by a ">" ('greater-than' character). This
is optionally followed by a single space. The remainder of the
syslog message follows this. The syslog event message MUST be
transmitted as visible (printing) characters.
If multiple syslog messages are included in a single ANS reply, each
is separated from the preceding with a CRLF. There is no ending
delimiter, but each syslog event message body length MUST be 1024
bytes or less, excluding BEEP framing overhead. Note that there MUST
NOT be a CRLF between the text of the final syslog event message and
the "END" marking the trailer of the BEEP frame.
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3.4 RAW Profile Semantics
The listener's opening BEEP MSG message has no semantics. (It is a
good place to put in an identifying greeting.) The initiator's ANS
replies MUST specify a facility, severity, and textual message, as
described in [1].
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4. The COOKED Profile
4.1 COOKED Profile Overview
The COOKED profile is designed for new implementations of syslog
protocol handlers. It provides a much finer grain of information
tagging, allowing a better degree of automation in processing.
Naturally, it includes more overhead as well in support of this.
The COOKED profile supports three elements of interest:
o The "iam" element identifies the sender to the receiver, allowing
each peer to name itself for the other, and specifying the roles
(device, relay, or collector) each is taking on.
o The "entry" element provides a parsed version of the syslog
entry, with the various fields of interest broken out.
o The "received" element contains an embedded "entry" or "received"
element, identifying a list of relays through which that "entry"
has passed.
4.2 COOKED Profile Identification and Initialization
The COOKED syslog profile is identified as
http://xml.resource.org/profiles/syslog/COOKED
in the BEEP "profile" element during channel creation.
During channel creation, the corresponding "profile" element in the
BEEP "start" element may contain an "iam" element. If channel
creation is successful, then before sending the corresponding reply,
the BEEP peer processes the "iam" element and includes the resulting
response in the reply. This response will be an "ok" element or an
"error" element. The choice of which element is returned is
dependant on local provisioning of the recipient. Including an "iam"
in the initial "start" element has exactly the same semantics as
passing it as the first MSG message on the channel.
4.3 COOKED Profile Message Syntax
All BEEP messages in this profile have a MIME Content-Type[5] of
text/xml. The syntax of the individual elements is specified in
Section 7.
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4.4 COOKED Profile Message Semantics
Initiators issue two elements: "iam" and "entry", each using a "MSG"
message. The listener issues "ok" in "RPY" messages and "error" in
"ERR" messages. (See [2]'s Section 2.3.1 for the definitions of the
"error" and "ok" elements.)
4.4.1 The IAM Element
The "iam" element serves to identify a device, relay, or collector
at one end of the BEEP channel to the device, relay, or collector at
the other end of the channel. The "iam" element includes the type of
peer (device, relay, or collector), the fully qualified domain name
of the peer, and the IP address of the peer. The character data of
the element is free-form human-readable text. It may be used to
further identify the peer, such as by describing the physical
location of the machine.
An "iam" element may be sent by the initiator of the channel at any
time. The listener responds to an "iam" element with an "ok"
(indicating acceptance), or an "error" (indicating rejection). The
identity and role in effect is specified by the most recent "iam"
not answered with an "error".
An "iam" could be rejected (with an "error" element) by the listener
if the privacy or authentication that has been negotiated is
inadequate or if the authenticated user does not have authorization
to serve in the specified role. It is expected that most
installations will require an "iam" from the peer before accepting
any "entry" messages.
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For example, a successful creation might look like this:
I: MSG 0 10 . 1832 247
I: Content-type: text/xml
I:
I: <start number='1'>
I: <profile
I: uri='http://xml.resource.org/profiles/syslog/COOKED'>
I: <![CDATA[ <iam fqdn='lowry.example.com' ip='10.0.0.27'
I: type='device'/> ]]>
I: </profile>
I: </start>
L: END
L: RPY 0 10 . 704 126
L: Content-type: text/xml
L:
L: <profile uri='http://xml.resource.org/profiles/syslog/COOKED'>
L: <![CDATA[ <ok /> ]]>
L: </profile>
L: END
A creation with an embedded "iam" that fails might look like this:
C: MSG 0 12 . 1832 247
C: Content-type: text/xml
C:
C: <start number='1'>
C: <profile
C: uri='http://xml.resource.org/profiles/syslog/COOKED'>
C: <![CDATA[ <iam fqdn='tuttle.example.com' ip='10.0.0.29'
C: type='relay'/> ]]>
C: </profile>
C: </start>
C: END
S: RPY 0 12 . 704 229
S: Content-type: text/xml
S:
S: <profile uri='http://xml.resource.org/profiles/syslog/COOKED'>
S: <![CDATA[
S: <error code='535'>User 'buttle.example.com' not allowed
S: to "iam" for 'tuttle.example.com'</error> ]]>
S: </profile>
S: END
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4.4.2 The ENTRY Element
The "entry" element carries the details of a single syslog entry.
The attributes of an "entry" element include "facility", "severity",
"timestamp", "processName", and "processID". "Facility" and
"severity" have the semantics defined in [1]'s 3.2. The other
attributes have the semantics as in Section 4 of [1]. "Timestamp" is
represented according to [8].
If the client is a relay, the "entry" SHOULD also contain the
attributes "deviceFQDN" and "deviceIP", specifying the FQDN and IP
address of the device that originally created the entry. These
attributes may be added by either the relay or the originating
device.
The character data for the element is the unstructured syslog event
message being logged. In this case, "processName" and "processID"
SHOULD be those of the original device generating the entry (unless
the device cannot supply a processName and processID). The
"timestamp" SHOULD be that of the original entry generation time,
rather than the time the entry was passed outward from the relay.
The original contents of the syslog message MUST be preserved in the
CDATA of the "entry" element; this includes preservation of exact
content during translation from the UDP or RAW formats. In
particular, the timestamps MUST NOT be rewritten in the CDATA of the
"entry" element, the process name and ID MUST NOT be removed from
the CDATA even if presented in the "entry" attributes as well, and
so on.
The "entry" element may also contain an "xml:lang" attribute,
indicating the language in which the CDATA content of the tag is
presented, as described in [4].
The "entry" element is answered with either an empty "ok" element if
everything was successful, or a standard "error" element if there
was a problem. An "entry" element can be rejected if no "iam"
element has been accepted by the listener. It can also be rejected
if the user authenticated on the BEEP session (if any) does not have
the authority to generate (as a device) or relay that entry.
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A successful exchange of an "entry" element may look like this:
C: MSG 1 0 . 2058 162
C: Content-Type: text/xml
C:
C: <entry facility='24' severity='5' timestamp='20001027T132108Z'
C: processName='imxpd' processID='141'>
C: No 27B/6 available</entry>
C: END
S: RPY 1 0 . 933 33
S: Content-Type: text/xml
S:
S: <ok/>
S: END
Here, the device IP address and FQDN are taken from the "iam"
element, if any, or from the underlying connection information.
An example where an "entry" element is rejected with an "error"
element:
C: MSG 1 2 . 2220 238
C: Content-Type: text/xml
C:
C: <entry facility='24' severity='5' timestamp='20001027T132215Z'
C: deviceFQDN='jack.invisible.net' deviceIP='10.0.0.83'
C: processName='imxpd' processID='141'>
C: Replacement device found in nostril.
C: </entry>
C: END
S: ERR 1 2 . 966 101
S: Content-Type: text/xml
S:
S: <error code='554'>Not allowed to relay for
S: jack.invisible.net</error>
S: END
Here, the client attempts to relay an entry on behalf of
jack.example.com, but the entry is refused by the collector for
administrative reasons. This may occur, for example, if
lowry.example.com is in a different department than jack.example.com.
4.4.3 The RECEIVED Element
The "received" element serves to deliver a single "entry" element,
along with a list of the relays through which that element has
passed. Each "received" element contains either another "received"
element or an "entry" element. Each "received" element names a FQDN
and IP address of the relay or collector that received the element.
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Each relay, before passing on the message, wraps the entire received
element in a new "received" element listing the IP address and the
FQDN (if any) of the interface over which the "trace" element was
received. The final collector may or may not wrap the "received"
element itself, depending on provisioning by the administrator.
The rationale for nesting "received" elements is to allow tagging of
the enclosed element without modification thereof. That is, the
relay wrapping the element can do so without disturbing any
cryptographic signatures that may already be on the embedded
elements.
Each "received" element has a "FQDN" attribute and an "IP"
attribute. The FQDN attribute SHOULD be the fully qualified domain
name of the interface over which the "trace" element was received.
(The FQDN can be omitted if that interface has no DNS entry.) The
element also MAY include a "timestamp" attribute indicating the time
at which the element was received.
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For example:
C: MSG 1 0 . 2458 672
C: Content-Type: text/xml
C:
C: <received FQDN='jack.inforet.example.com' IP='10.0.0.204'>
C: <received FQDN='f-wall.inforet.example.com' IP='10.0.0.200'>
C: <received FQDN='f-wall.records.example.com' IP='10.0.0.100'>
C: <received FQDN='kurtzman.records.example.com'
C: IP='10.0.0.107'>
C: <received FQDN='lowry.records.example.com' IP='10.0.0.103'/>
C: <entry facility='24' severity='5'
C: timestamp='20001027T132215Z'
C: deviceFQDN='screen.lowry.records.example.com'
C: deviceIP='10.0.0.105' processID='185'
C: processName='tuner'>
C: <29>12:22 tuner[185]: Casablanca initiated
C: </entry>
C: </received>
C: </received>
C: </received>
C: </received>
C: </received>
C: END
S: RPY 1 0 . 1067 33
S: Content-Type: text/xml
S:
S: <ok/>
S: END
Here we see Lowry's screen announce the beginning of today's movie.
This information is passed out of Lowry's department and into Jack's
department for logging.
The choice of whether to generate an "entry" element or a "received"
element at the first relay is controlled by local provisioning. When
a relay receives a "received" element, it MUST add a "received"
element describing itself before passing it on. When a collector
receives a "received" element, it MUST act upon the enclosed "entry"
element as it would had the collector received it without trace
information. What the collector does with the "received" elements is
left to local configuration.
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5. Additional Provisioning
In more advanced configurations, syslog devices, relays, and
collectors can be configured to support various delivery priorities.
Multiple channels running the same profile can be opened between two
peers, with higher priority syslog messages routed to a channel that
is given more bandwidth. Such provisioning is a local matter.
syslog[1] discusses a number of reasons why privacy and
authentication of syslog entry messages may be important in a
networked computing environment. The nature of BEEP allows for
convenient layering of authentication and privacy over any BEEP
channel.
5.1 Message Authenticity
Section 5.2 of [1] discusses the dangers of unauthenticated syslog
entries. To prevent inauthentic syslog event messages from being
accepted, configure syslog peers to require the use of a strong
authentication technology for the BEEP session.
If provisioned for message authentication, implementations SHOULD
use SASL mechanism DIGEST-MD5[7] to provision this service.
5.2 Message Replay
Section 5.3.4 of [1] discusses the dangers of syslog message replay.
To prevent syslog event messages from being replayed, configure
syslog peers to require the use of a strong authentication
technology for the BEEP session.
If provisioned to detect message replay, implementations SHOULD use
SASL mechanism DIGEST-MD5[7] to provision this service.
5.3 Message Integrity
Section 5.5 of [1] discusses the dangers of syslog event messages
being maliciously altered by an attacker. To prevent messages from
being altered, configure syslog peers to require the use of a strong
authentication technology for the BEEP session.
If provisioned to protect message integrity, implementations SHOULD
use SASL mechanism DIGEST-MD5[7] to provision this service.
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5.4 Message Observation
Section 5.6 of [1] discusses the dangers (and benefits) of syslog
messages being visible at intermediate points along the transmission
path between device and collector. To prevent messages from being
viewed by an attacker, configure syslog peers to require the use of
a transport security profile for the BEEP session. (However, other
traffic characteristics, e.g., volume and timing of transmissions,
remain observable.)
If provisioned to secure messages against unauthorized observation,
implementations SHOULD use the TLS profile[2] to provision this
service. The cipher algorithm used SHOULD be
TLS_RSA_WITH_3DES_EDE_CBC_SHA.
5.5 Summary of Recommended Practices
For the indicated protections, implementations SHOULD be configured
to use the indicated mechanisms:
Desired Protection SHOULD tune using
------------------ -----------------
Authentication http://xml.resource.org/profiles/sasl/DIGEST-MD5
+ Replay http://xml.resource.org/profiles/sasl/DIGEST-MD5
+ Integrity http://xml.resource.org/profiles/sasl/DIGEST-MD5
+ Observation http://xml.resource.org/profiles/TLS
BEEP peer identities used for authentication SHOULD correspond to
the FQDN of the initiating peer. That is, a relay running on
relay.example.com should use a "user ID" of "relay.example.com"
within the SASL authentication profiles, as well as in the FQDN of
the "iam" element.
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6. Initial Registrations
6.1 Registration: The RAW Profile
Profile Identification: http://xml.resource.org/profiles/syslog/RAW
Messages exchanged during Channel Creation: None
Messages starting one-to-one exchanges: Anything
Messages in positive replies: None
Messages in negative replies: None
Messages in one-to-many exchanges: Anything
Message Syntax: See Section 3.3
Message Semantics: See Section 3.4
Contact Information: See the "Authors' Addresses" section of this
memo
6.2 Registration: The COOKED Profile
Profile Identification: http://xml.resource.org/profiles/syslog/RAW
Messages exchanged during Channel Creation: iam
Messages starting one-to-one exchanges: iam, entry, trace
Messages in positive replies: ok
Messages in negative replies: error
Messages in one-to-many exchanges: None
Message Syntax: See Section 4.3
Message Semantics: See Section 4.4
Contact Information: See the "Authors' Addresses" section of this
memo
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7. The syslog DTD
The following is the DTD defining the valid elements for the syslog
over BEEP mapping.
<!--
DTD for syslog over BEEP, as of 2000-10-10
Refer to this DTD as:
<!ENTITY % SYSLOG PUBLIC "-//Blocks//DTD SYSLOGRELIABLE//EN"
"http://xml.resource.org/syslog/syslog.dtd">
%SYSLOG;
-->
<!--
Contents
Overview
Includes
Profile Summaries
Entity Definitions
Operations
iam
entry
-->
<!--
Overview
Syslog packets delivered via BEEP
-->
<!-- Includes -->
<!ENTITY % BEEP PUBLIC "-//Blocks//DTD BEEP//EN"
"http://xml.resource.org/profiles/BEEP/beep.dtd">
%BEEP;
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<!--
Profile summaries
BEEP profile http://xml.resource.org/profiles/syslog/RAW
role MSG ANS ERR
==== === === ===
L text text text
BEEP profile http://xml.resource.org/profiles/syslog/COOKED
role MSG RPY ERR
==== === === ===
I or L iam ok error
I or L entry ok error
I or L trace ok error
-->
<!--
Entity Definitions
entity syntax/reference example
====== ================ =======
a fully qualified domain name
FQDN See [RFC-1034] www.example.com
a dotted-quad IP address
IP 1*3DIGIT "." 1*3DIGIT "."
1*3DIGIT "." 1*3DIGIT
10.0.0.27
a syslog facility
FACILITY See [1]
1*3DIGIT 80
a syslog severity
SEVERITY See [1]
DIGIT 4
a timestamp See ISO 8601 20001007T135834Z
TIMESTAMP
-->
<!ENTITY % FQDN "CDATA">
<!ENTITY % IP "CDATA">
<!ENTITY % FACILITY "CDATA">
<!ENTITY % SEVERITY "CDATA">
<!ENTITY % TIMESTAMP "CDATA">
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<!--
The iam element declares the role and identity of the peer
issuing it. The contents of the element may include human-readable
informative text, such as the physical location of the computer
issuing the "iam".
-->
<!ELEMENT iam (#PCDATA)>
<!ATTLIST iam
fqdn %FQDN; #REQUIRED
ip %IP; #REQUIRED
type (device|relay|collector) #REQUIRED>
<!--
The entry element conveys a single syslog message.
-->
<!ELEMENT entry (#PCDATA)>
<!ATTLIST entry
xml:lang %LANG; "i-default"
facility %FACILITY; #REQUIRED
severity %SEVERITY; #REQUIRED
timestamp %TIMESTAMP; #IMPLIED
processName %ATEXT; #IMPLIED
processID %ATEXT; #IMPLIED
deviceFQDN %FQDN; #IMPLIED
deviceIP %IP; #IMPLIED>
<!--
The relay element conveys a single syslog message,
along with a list of relays through which it has passed.
-->
<!ELEMENT received (received|empty)>
<!ATTLIST received
FQDN %FQDN; #IMPLIED
IP %IP; #REQUIRED>
<!-- End of DTD -->
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8. Reply Codes
The following error codes are used in the protocol:
code meaning
==== =======
421 service not available
451 requested action aborted
(e.g., local error in processing)
454 temporary authentication failure
500 general syntax error
(e.g., poorly-formed XML)
501 syntax error in parameters
(e.g., non-valid XML)
504 parameter not implemented
530 authentication required
534 authentication mechanism insufficient
(e.g., too weak, sequence exhausted, etc.)
535 authentication failure
537 action not authorized for user
538 authentication mechanism requires encryption
550 requested action not taken
(e.g., no requested profiles are acceptable)
553 parameter invalid
554 transaction failed
(e.g., policy violation)
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9. Security Considerations
Consult Section 5 of [1] for a discussion of security issues for the
syslog service. In addition, since the RAW and COOKED profiles are
defined using the BEEP framework, consult [2]'s Section 8 for a
discussion of BEEP-specific security issues.
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References
[1] Lonvick, C., "syslog Protocol", draft-ietf-syslog-syslog-02
(work in progress), November 2000.
[2] Rose, M.T., "The Blocks Extensible Exchange Protocol
Framework", draft-ietf-beep-framework-04 (work in progress),
October 2000.
[3] Mockapetris, P.V., "Domain names - concepts and facilities",
RFC 1034, STD 13, Nov 1987.
[4] Alvestrand, H., "Tags for the Identification of Languages", RFC
1766, March 1995.
[5] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046, November
1996.
[6] Gulbrandsen, A., Vixie, P. and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782,
February 2000.
[7] Leach, P. and C. Newman, "Using Digest Authentication as a SASL
Mechanism", RFC 2831, May 2000.
[8] International Organization for Standardization, "Data elements
and interchange formats - Information exchange -
Representation of dates and times", International Standard
8601, June 1988.
[9] mailto:calabrese@merck.com
[10] mailto:kzm@cisco.com
[11] mailto:bazsi@balabit.hu
[12] mailto:djw@bbn.com
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Authors' Addresses
Darren New
Invisible Worlds, Inc.
1179 North McDowell Boulevard
Petaluma, CA 94954-6559
US
Phone: +1 707 789 3700
EMail: dnew@invisible.net
URI: http://invisible.net/
Marshall T. Rose
Invisible Worlds, Inc.
1179 North McDowell Boulevard
Petaluma, CA 94954-6559
US
Phone: +1 707 789 3700
EMail: mrose@invisible.net
URI: http://invisible.net/
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Appendix A. History of Significant Changes
A.1 Significant Changes Since syslog-reliable-00
Multiple consecutive relays have been clarified.
Multiple syslog entries may appear in a single ANS reply in the RAW
profile, to reduce overhead.
The "iam" element is no longer answered by an "iam" element. A
separate exchange is necessary, allowing either peer to reject the
other's "iam".
The "timestamp" attribute is compatible with ISO 8601 now.
The "trace" element is added.
A.2 Significant Changes Since syslog-reliable-01
Additional wording about retaining the content of "entry"'s CDATA is
added.
The "trace" element is removed, with the "received" element being
substituted and made nestable.
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Appendix B. Acknowledgements
The author gratefully acknowledges the contributions of Christopher
Calabrese[9], Keith McCloghrie[10], Balazs Scheidler[11], and David
Waitzman[12].
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Full Copyright Statement
Copyright (C) The Internet Society (2000). All Rights Reserved.
This document and translations of it may be copied and furnished to
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the copyright notice or references to the Internet Society or other
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The limited permissions granted above are perpetual and will not be
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Acknowledgement
Funding for the RFC editor function is currently provided by the
Internet Society.
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