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syslog-ng Open Source Edition 3.33 - Administration Guide

Preface Introduction to syslog-ng The concepts of syslog-ng Installing syslog-ng The syslog-ng OSE quick-start guide The syslog-ng OSE configuration file source: Read, receive, and collect log messages
How sources work default-network-drivers: Receive and parse common syslog messages internal: Collecting internal messages file: Collecting messages from text files wildcard-file: Collecting messages from multiple text files linux-audit: Collecting messages from Linux audit logs network: Collecting messages using the RFC3164 protocol (network() driver) nodejs: Receiving JSON messages from nodejs applications mbox: Converting local email messages to log messages osquery: Collect and parse osquery result logs pipe: Collecting messages from named pipes pacct: Collecting process accounting logs on Linux program: Receiving messages from external applications python: writing server-style Python sources python-fetcher: writing fetcher-style Python sources snmptrap: Read Net-SNMP traps sun-streams: Collecting messages on Sun Solaris syslog: Collecting messages using the IETF syslog protocol (syslog() driver) system: Collecting the system-specific log messages of a platform systemd-journal: Collecting messages from the systemd-journal system log storage systemd-syslog: Collecting systemd messages using a socket tcp, tcp6, udp, udp6: Collecting messages from remote hosts using the BSD syslog protocol— OBSOLETE unix-stream, unix-dgram: Collecting messages from UNIX domain sockets stdin: Collecting messages from the standard input stream
destination: Forward, send, and store log messages
amqp: Publishing messages using AMQP collectd: sending metrics to collectd elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher (DEPRECATED) elasticsearch-http: Sending messages to Elasticsearch HTTP Bulk API file: Storing messages in plain-text files graphite: Sending metrics to Graphite Sending logs to Graylog hdfs: Storing messages on the Hadoop Distributed File System (HDFS) Posting messages over HTTP http: Posting messages over HTTP without Java kafka: Publishing messages to Apache Kafka (Java implementation) kafka(): Publishing messages to Apache Kafka (C implementation, using the librdkafka client) loggly: Using Loggly logmatic: Using mongodb: Storing messages in a MongoDB database mqtt() destination: sending messages from a local network to an MQTT broker network: Sending messages to a remote log server using the RFC3164 protocol (network() driver) osquery: Sending log messages to osquery's syslog table pipe: Sending messages to named pipes program: Sending messages to external applications pseudofile() python: writing custom Python destinations redis: Storing name-value pairs in Redis riemann: Monitoring your data with Riemann slack: Sending alerts and notifications to a Slack channel smtp: Generating SMTP messages (email) from logs snmp: Sending SNMP traps Splunk: Sending log messages to Splunk sql: Storing messages in an SQL database stomp: Publishing messages using STOMP Sumo Logic destinations: sumologic-http() and sumologic-syslog() syslog: Sending messages to a remote logserver using the IETF-syslog protocol syslog-ng(): Forward logs to another syslog-ng node tcp, tcp6, udp, udp6: Sending messages to a remote log server using the legacy BSD-syslog protocol (tcp(), udp() drivers) Telegram: Sending messages to Telegram unix-stream, unix-dgram: Sending messages to UNIX domain sockets usertty: Sending messages to a user terminal: usertty() destination Write your own custom destination in Java or Python Client-side failover
log: Filter and route log messages using log paths, flags, and filters Global options of syslog-ng OSE TLS-encrypted message transfer template and rewrite: Format, modify, and manipulate log messages parser: Parse and segment structured messages db-parser: Process message content with a pattern database (patterndb) Correlating log messages Enriching log messages with external data Statistics of syslog-ng Multithreading and scaling in syslog-ng OSE Troubleshooting syslog-ng Best practices and examples The syslog-ng manual pages Creative Commons Attribution Non-commercial No Derivatives (by-nc-nd) License Glossary

Element: ruleset




A container element to group log patterns for an application or program. A <patterndb> element may contain any number of <ruleset> elements.

  • name: The name of the application. Note that the function of this attribute is to make the database more readable, syslog-ng uses the <pattern> element to identify the applications sending log messages.

  • id: A unique ID of the application, for example, the md5 sum of the name attribute.

  • patterns

  • rules

  • actions

  • tags

  • description: OPTIONAL — A description of the ruleset or the application.

  • url: OPTIONAL — An URL referring to further information about the ruleset or the application.

  • rule_urls: OPTIONAL — To list multiple URLs referring to further information about the ruleset or the application, enclose the <url> elements into an <urls> element.

<ruleset name='su' id='480de478-d4a6-4a7f-bea4-0c0245d361e1'>

Element: patterns




A container element. A <patterns> element may contain any number of <pattern> elements.



  • pattern: The name of the application — syslog-ng matches this value to the ${PROGRAM} header of the syslog message to find the rulesets applicable to the syslog message.

    Specifying multiple patterns is useful if two or more applications have different names (that is, different ${PROGRAM} fields), but otherwise send identical log messages.

    It is not necessary to use multiple patterns if only the end of the ${PROGRAM} fields is different, use only the beginning of the ${PROGRAM} field as the pattern. For example, the Postfix email server sends messages using different process names, but all of them begin with the postfix string.

    You can also use parsers in the program pattern if needed, and use the parsed results later. For example: <pattern>postfix\@ESTRING:.postfix.component:[@</pattern>

    NOTE: If the <pattern> element of a ruleset is not specified, syslog-ng OSE will use this ruleset as a fallback ruleset: it will apply the ruleset to messages that have an empty PROGRAM header, or if none of the program patterns matched the PROGRAM header of the incoming message.


Using parsers in the program pattern:


Element: rules




A container element for the rules of the ruleset.



    <rule provider='me' id='182437592347598' class='system'>
            <pattern>Accepted @QSTRING:SSH.AUTH_METHOD: @ for@QSTRING:SSH_USERNAME: @from\ @QSTRING:SSH_CLIENT_ADDRESS: @port @NUMBER:SSH_PORT_NUMBER:@ ssh2</pattern>

Element: rule




An element containing message patterns and how a message that matches these patterns is classified.

NOTE: If the following characters appear in the message, they must be escaped in the rule as follows:

  • @: Use @@, for example,

  • <: Use &lt;

  • >: Use &gt;

  • &: Use &amp;

The <rules> element may contain any number of <rule> elements.

  • provider: The provider of the rule. This is used to distinguish between who supplied the rule, that is, if it has been created by One Identity, or added to the XML by a local user.

  • id: The globally unique ID of the rule.

  • class: The class of the rule — syslog-ng assigns this class to the messages matching a pattern of this rule.

  • context-id: OPTIONAL — An identifier to group related log messages when using the pattern database to correlate events. The ID can be a descriptive string describing the events related to the log message (for example, ssh-sessions for log messages related to SSH traffic), but can also contain macros to generate IDs dynamically. When using macros in IDs, see also the context-scope attribute. Starting with syslog-ng OSE version 3.5, if a message is added to a context, syslog-ng OSE automatically adds the identifier of the context to the .classifier.context_id macro of the message. For details on correlating messages, see Correlating log messages using pattern databases.

    NOTE: The syslog-ng OSE application determines the context of the message after the pattern matching is completed. This means that macros and name-value pairs created by the matching pattern database rule can be used as context-id macros.

  • context-timeout: OPTIONAL — The number of seconds the context is stored. Note that for high-traffic log servers, storing open contexts for long time can require significant amount of memory. For details on correlating messages, see Correlating log messages using pattern databases.

  • context-scope: OPTIONAL — Specifies which messages belong to the same context. This attribute is used to determine the context of the message if the context-id does not specify any macros. Usually, context-scope acts a filter for the context, with context-id refining the filtering if needed. The following values are available:

    • process: Only messages that are generated by the same process of a client belong to the same context, that is, messages that have identical ${HOST}, ${PROGRAM} and ${PID} values. This is the default behavior of syslog-ng OSE if context-scope is not specified.

    • program: Messages that are generated by the same application of a client belong to the same context, that is, messages that have identical ${HOST} and ${PROGRAM} values.

    • host: Every message generated by a client belongs to the same context, only the ${HOST} value of the messages must be identical.

    • global: Every message belongs to the same context.

    NOTE: Using the context-scope attribute is significantly faster than using macros in the context-id attribute.

    For details on correlating messages, see Correlating log messages using pattern databases.

<rule provider='example' id='f57196aa-75fd-11dd-9bba-001e6806451b' class='violation'>

The following example specifies attributes for correlating messages as well. For details on correlating messages, see Correlating log messages using pattern databases.

<rule provider='example' id='f57196aa-75fd-11dd-9bba-001e6806451b' class='violation' context-id='same-session' context-scope='process' context-timeout='360'>
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