NAME
syslog-ng.conf - syslog-ng configuration file
SYNOPSIS
syslog-ng.conf
DESCRIPTION
NOTE: This manual page covers both editions of syslog-ng: syslog-ng
Open Source Edition and the commercial syslog-ng Premium Edition.
Features that are only included in the Premium Edition are marked with
an asterisk (*). For details, see the official syslog-ng website:
http://www.balabit.com/network-security/syslog-ng/.
This manual page is only an abstract; for the complete documentation of
syslog-ng, see
The syslog-ng Administrator Guide [1].
The syslog-ng application is a flexible and highly scalable system
logging application. Typically, syslog-ng is used to manage log
messages and implement centralized logging, where the aim is to collect
the log messages of several devices on a single, central log server.
The different devices - called syslog-ng clients - all run syslog-ng,
and collect the log messages from the various applications, files, and
other sources. The clients send all important log messages to the
remote syslog-ng server, where the server sorts and stores them.
The syslog-ng application reads incoming messages and forwards them to
the selected destinations. The syslog-ng application can receive
messages from files, remote hosts, and other sources.
Log messages enter syslog-ng in one of the defined sources, and are
sent to one or more destinations.
Sources and destinations are independent objects; log paths define what
syslog-ng does with a message, connecting the sources to the
destinations. A log path consists of one or more sources and one or
more destinations; messages arriving to a source are sent to every
destination listed in the log path. A log path defined in syslog-ng is
called a log statement.
Optionally, log paths can include filters. Filters are rules that
select only certain messages, for example, selecting only messages sent
by a specific application. If a log path includes filters, syslog-ng
sends only the messages satisfying the filter rules to the destinations
set in the log path.
CONFIGURING SYSLOG-NG
Global objects (e.g., sources, destinations, log paths, or filters) are
defined in the syslog-ng configuration file. Object definitions consist
of the following elements:
o Type of the object: One of source, destination, log, filter,
parser, rewrite rule, or template.
o Identifier of the object: A unique name identifying the object.
When using a reserved word as an identifier, enclose the identifier
in quotation marks.
Tip
Use identifiers that refer to the type of the object they identify.
For example, prefix source objects with s_, destinations with d_,
and so on.
o Parameters: The parameters of the object, enclosed in braces
{parameters}.
o Semicolon: Object definitions end with a semicolon (;).
The syntax is summarized as follows:
The syntax of log statements is as follows:
log {
source(s1); source(s2); ...
optional_element(filter1|parser1|rewrite1); optional_element(filter2|parser2|rewrite2);...
destination(d1); destination(d2); ...
flags(flag1[, flag2...]);
};
The following log statement sends all messages arriving to the
localhost to a remote server.
source s_localhost { tcp(ip(127.0.0.1) port(1999) ); };
destination d_tcp { tcp("10.1.2.3" port(1999); localport(999)); };
log { source(s_localhost); destination(d_tcp); };
The syslog-ng application has a number of global options governing DNS
usage, the timestamp format used, and other general points. Each option
may have parameters, similarly to driver specifications. To set global
options, add an option statement to the syslog-ng configuration file
using the following syntax:
options { option1(params); option2(params); ... };
The sources, destinations, and filters available in syslog-ng are
listed below. For details, see
The syslog-ng Administrator Guide [1].
Table 1. Source drivers available in syslog-ng
+----------------------------------------------+--------------------------------------------+
|Name | Description |
+----------------------------------------------+--------------------------------------------+
|internal() | Messages generated |
| | internally in syslog-ng. |
+----------------------------------------------+--------------------------------------------+
|file() | Opens the specified file |
| | and reads messages. |
+----------------------------------------------+--------------------------------------------+
|pipe(), fifo | Opens the specified named |
| | pipe and reads messages. |
+----------------------------------------------+--------------------------------------------+
|program() | Opens the specified |
| | application and reads |
| | messages from its standard |
| | output. |
+----------------------------------------------+--------------------------------------------+
|sun-stream(), | Opens the specified STREAMS device |
| sun-streams() | on Solaris |
| | systems |
| | and reads incoming messages. |
+----------------------------------------------+--------------------------------------------+
|syslog() | Listens for incoming messages using |
| | the new IETF-standard syslog |
| | protocol. |
+----------------------------------------------+--------------------------------------------+
|tcp(), tcp6() | Listens on the specified TCP port for |
| | incoming messages using the |
| | BSD-syslog |
| | protocol |
| | over IPv4 and IPv6 networks, |
| | respectively. |
+----------------------------------------------+--------------------------------------------+
|udp(), udp6() | Listens on the specified UDP port for |
| | incoming messages using the |
| | BSD-syslog |
| | protocol over |
| | IPv4 and IPv6 networks, respectively. |
+----------------------------------------------+--------------------------------------------+
|unix-dgram() | Opens the specified unix socket in |
| | SOCK_DGRAM |
| | mode and |
| | listens for incoming messages. |
+----------------------------------------------+--------------------------------------------+
|unix-stream() | Opens the specified unix socket in |
| | SOCK_STREAM |
| | mode and |
| | listens for incoming messages. |
+----------------------------------------------+--------------------------------------------+
Table 2. Destination drivers available in syslog-ng
+-----------------+--------------------------------------------+
|Name | Description |
+-----------------+--------------------------------------------+
|file() | Writes messages to the |
| | specified file. |
+-----------------+--------------------------------------------+
|logstore()* | Writes messages to the |
| | specified binary logstore |
| | file. |
| | *Available |
| | only in syslog-ng Premium |
| | Edition. |
+-----------------+--------------------------------------------+
|fifo(), pipe() | Writes messages to the specified named |
| | pipe. |
+-----------------+--------------------------------------------+
|program() | Forks and launches the specified |
| | program, and sends messages to its |
| | standard |
| | input. |
+-----------------+--------------------------------------------+
|sql() | Sends messages into an SQL database. |
| | In addition to the standard |
| | syslog-ng |
| | packages, the sql() destination |
| | requires |
| | database-specific packages to be |
| | installed. Refer to the |
| | section |
| | appropriate for your platform in ???. |
+-----------------+--------------------------------------------+
|syslog() | Sends messages to the specified remote |
| | host using the IETF-syslog protocol. |
| | The IETF |
| | standard supports message transport |
| | using the UDP, TCP, and TLS |
| | networking |
| | protocols. |
+-----------------+--------------------------------------------+
|tcp() and tcp6() | Sends messages to the specified TCP |
| | port of a remote host using the |
| | BSD-syslog |
| | protocol |
| | over IPv4 and IPv6, respectively. |
+-----------------+--------------------------------------------+
|udp() and udp6() | Sends messages to the specified UDP port |
| | of a remote host using the |
| | BSD-syslog |
| | protocol over |
| | IPv4 and IPv6, respectively. |
+-----------------+--------------------------------------------+
|unix-dgram() | Sends messages to the specified unix |
| | socket in |
| | SOCK_DGRAM |
| | style (BSD). |
+-----------------+--------------------------------------------+
|unix-stream() | Sends messages to the specified unix |
| | socket in |
| | SOCK_STREAM |
| | style (Linux). |
+-----------------+--------------------------------------------+
|usertty() | Sends messages to the terminal of the |
| | specified user, if the user is |
| | logged in. |
+-----------------+--------------------------------------------+
Table 3. Filter functions in syslog-ng
+-----------+--------------------------------+----------------------------------------------------------------------+
|Name | Synopsis | Description |
+-----------+--------------------------------+----------------------------------------------------------------------+
|facility() | facility(facility[,facility]) | Match messages |
| | | having one of the |
| | | listed facility |
| | | code. An alternate |
| | | syntax |
| | | permits the use an |
| | | arbitrary facility |
| | | codes. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|facility() | facility(<numeric facility | An alternate syntax for facility |
| | code>) | permitting |
| | | the |
| | | use of an arbitrary facility code. |
| | | Facility codes 0-23 are |
| | | predefined |
| | | and can be referenced by their |
| | | usual name. Facility codes |
| | | above |
| | | 24 are not defined but can be used |
| | | by this alternate syntax. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|filter() | filter(filtername) | Call another filter rule and evaluate |
| | | its value. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|host() | host(regexp) | Match messages by using a regular |
| | | expression against the hostname |
| | | field of |
| | | log messages. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|level() or | level(pri[,pri1..pri2[,pri3]]) | Match messages based on priority. |
|priority() | | |
+-----------+--------------------------------+----------------------------------------------------------------------+
|match() | match(regexp) | Match a regular expression to the |
| | | headers and the message itself |
| | | (i.e., the |
| | | values returned by the MSGHDR and |
| | | MSG |
| | | macros). Note that in syslog-ng |
| | | version |
| | | 2.1 and |
| | | earlier, the match() filter was |
| | | applied |
| | | only to |
| | | the text of the message, excluding the |
| | | headers. This |
| | | functionality |
| | | has been moved to the message() |
| | | filter. To |
| | | limit the scope of the match to a |
| | | specific part of the |
| | | message |
| | | (identified with a macro), use the |
| | | match(regexp |
| | | value("$MACRO")) |
| | | syntax. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|message() | message(regexp) | Match a regular expression to the text of the |
| | | log message, excluding |
| | | the headers (i.e., |
| | | the value returned by the MSG |
| | | macros). Note that |
| | | in syslog-ng version 2.1 and earlier, this |
| | | functionality was |
| | | performed by the match() |
| | | filter. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|netmask() | netmask(ip/mask) | Select only messages sent by a host whose IP |
| | | address belongs to the |
| | | specified IP subnet. |
| | | Note that this filter checks the IP address of |
| | | the |
| | | last-hop relay (the |
| | | host that actually sent the message to |
| | | syslog-ng), |
| | | not the contents of |
| | | the HOST field of the |
| | | message. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|program() | program(regexp) | Match messages by using a regular expression |
| | | against the program name |
| | | field of log |
| | | messages. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|source() | string | Select messages of a source statement. This |
| | | filter can be used in |
| | | embedded log |
| | | statements if the parent statement contains |
| | | multiple source |
| | | groups -- only |
| | | messages originating from the selected source |
| | | group are sent to |
| | | the destination of the embedded log statement. |
+-----------+--------------------------------+----------------------------------------------------------------------+
|tags() | tag | Select messages labeled with the specified tag. |
| | | Every message |
| | | automatically has |
| | | the tag of its source in |
| | | .source.<id_of_the_source_statement> |
| | | format. This option |
| | | is available only in syslog-ng 3.1 and later. |
+-----------+--------------------------------+----------------------------------------------------------------------+
FILES
/opt/syslog-ng/etc/syslog-ng/
/opt/syslog-ng/etc/syslog-ng/syslog-ng.conf
SEE ALSO
syslog-ng(8)
The syslog-ng Administrator Guide [1]
If you experience any problems or need help with syslog-ng, visit the
syslog-ng mailing list [2]
For news and notifications about the documentation of syslog-ng, visit
the BalaBit Documentation Blog[3].
AUTHOR
This manual page was written by the BalaBit Documentation Team
<documentation@balabit.com>.
COPYRIGHT
Copyright (C) 2000-2009 BalaBit IT Security Ltd. Published under the
Creative Commons Attribution-Noncommercial-No Derivative Works
(by-nc-nd) 3.0 license. See http://creativecommons.org/ for details.
The latest version is always available at
http://www.balabit.com/support/documentation.
NOTES
1.
The syslog-ng Administrator Guide
http://www.balabit.com/support/documentation/
2.
syslog-ng mailing list
https://lists.balabit.hu/mailman/listinfo/syslog-ng
3. BalaBit Documentation Blog
http://robert.blogs.balabit.com
11/30/2009