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syslog-ng Premium Edition 7.0.12 - Administration Guide

Preface Introduction to syslog-ng The concepts of syslog-ng Installing syslog-ng The syslog-ng PE quick-start guide The syslog-ng PE configuration file Collecting log messages — sources and source drivers
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 network: Collecting messages using the RFC3164 protocol (network() driver) osquery: Collect and parse osquery result logs pipe: Collecting messages from named pipes 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 unix-stream, unix-dgram: Collecting messages from UNIX domain sockets windowsevent: Collecting Windows event logs
Sending and storing log messages — destinations and destination drivers
elasticsearch: Sending messages directly to Elasticsearch version 1.x elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher file: Storing messages in plain-text files hdfs: Storing messages on the Hadoop Distributed File System (HDFS) http: Posting messages over HTTP kafka: Publishing messages to Apache Kafka logstore: Storing messages in encrypted files mongodb: Storing messages in a MongoDB database network: Sending messages to a remote log server using the RFC3164 protocol (network() driver) pipe: Sending messages to named pipes program: Sending messages to external applications python: writing custom Python destinations smtp: Generating SMTP messages (e-mail) from logs splunk-hec: Sending messages to Splunk HTTP Event Collector sql: Storing messages in an SQL database syslog: Sending messages to a remote logserver using the IETF-syslog protocol syslog-ng: Forwarding messages and tags 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) unix-stream, unix-dgram: Sending messages to UNIX domain sockets usertty: Sending messages to a user terminal — usertty() destination Client-side failover
Routing messages: log paths, flags, and filters Global options of syslog-ng PE TLS-encrypted message transfer Advanced Log Transfer Protocol Reliability and minimizing the loss of log messages Manipulating messages parser: Parse and segment structured messages Processing message content with a pattern database Correlating log messages Enriching log messages with external data Monitoring statistics and metrics of syslog-ng Multithreading and scaling in syslog-ng PE Troubleshooting syslog-ng Best practices and examples The syslog-ng manual pages About us

Change an old source driver to the network() driver

To replace your existing tcp(), tcp6(), udp(), udp6() sources with a network() source, complete the following steps.

  1. Replace the driver with network. For example, replace udp( with network(

  2. Set the transport protocol.

    • If you used TLS-encryption, add the transport("tls") option, then continue with the next step.

    • If you used the tcp or tcp6 driver, add the transport("tcp") option.

    • If you used the udp or udp driver, add the transport("udp") option.

  3. If you use IPv6 (that is, the udp6 or tcp6 driver), add the ip-protocol(6) option.

  4. If you did not specify the port used in the old driver, check network() source options and verify that your clients send the messages to the default port of the transport protocol you use. Otherwise, set the appropriate port number in your source using the port() option.

  5. All other options are identical. Test your configuration with the syslog-ng --syntax-only command.

    The following configuration shows a simple tcp source.

    source s_old_tcp {
            ip( port(1999)

    When replaced with the network() driver, it looks like this.

    source s_new_network_tcp {
            ip( port(1999)

unix-stream, unix-dgram: Collecting messages from UNIX domain sockets

The unix-stream() and unix-dgram() drivers open an AF_UNIX socket and start listening on it for messages. The unix-stream() driver is primarily used on Linux and uses SOCK_STREAM semantics (connection oriented, no messages are lost), while unix-dgram() is used on BSDs and uses SOCK_DGRAM semantics: this may result in lost local messages if the system is overloaded.

To avoid denial of service attacks when using connection-oriented protocols, the number of simultaneously accepted connections should be limited. This can be achieved using the max-connections() parameter. The default value of this parameter is quite strict, you might have to increase it on a busy system.

Both unix-stream and unix-dgram have a single required argument that specifies the filename of the socket to create. For the list of available optional parameters, see unix-stream() and unix-dgram() source options

unix-stream(filename [options]);
unix-dgram(filename [options]);


syslogd on Linux originally used SOCK_STREAM sockets, but some distributions switched to SOCK_DGRAM around 1999 to fix a possible DoS problem. On Linux you can choose to use whichever driver you like as syslog clients automatically detect the socket type being used.

Example: Using the unix-stream() and unix-dgram() drivers
source s_stream {
    unix-stream("/dev/log" max-connections(10));
source s_dgram {

windowsevent: Collecting Windows event logs

Event log messages collected by the Windows Event Collector for syslog-ng PE use this special source. To collect Windows event log messages, include this source in one of your source statements.

The Windows Event Collector tool for syslog-ng PE collects the log messages of Windows-based hosts in Unix datagram sockets, and then forwards them to a syslog-ng PE server over HTTPS (using TLS encryption and mutual authentication). syslog-ng PE reads the log messages using the windowsevent() source, and then parses the logs into key-value paris using the XML parser.

For more information, see Windows Event Collector Administration Guide.

source s_wec {

windowsevent() source options

The windowsevent() driver has the following options:

Type: string
Default: ".windowsevent."

Description: The prefix that you wish to append to the key-value pairs.

If you want to send Windows event logs to SDATA, then set prefix(".SDATA."). This can be useful, for example, when you forward Windows event logs to a syslog-ng Store Box.

Type: string
Default: /opt/syslog-ng/var/run/wec.sock

Description: The path to the Unix domain socket to read messages from.

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