The syslog-ng Administrator Guide

Some of the parameters affecting message formatting and sending are common for almost all destinations. The following options are available for every destination, except for sql() and usertty().

	Note
	The usertty destination does not support templates.

The file driver is one of the most important destination drivers in syslog-ng. It allows to output messages to the specified file, or to a set of files.

The destination filename may include macros which get expanded when the message is written, thus a simple file() driver may crete several files. For more information on available macros see Section 9.5, “Macros”.

If the expanded filename refers to a directory which does not exist, it will be created depending on the create_dirs() setting (both global and a per destination option).

	Note
	When using the file() destination, update the configuration of your log rotation program to rotate these files. Otherwise, the log files can become very large.

Warning

Since the state of each created file must be tracked by syslog-ng, it consumes some memory for each file. If no new messages are written to a file within 60 seconds (controlled by the time_reap() global option), it is closed, and its state is freed. Exploiting this, a DoS attack can be mounted against the system. If the number of possible destination files and its needed memory is more than the amount available on the syslog-ng server. The most suspicious macro is $PROGRAM, where the number of possible variations is rather high. Do not use the $PROGRAM macro in insecure environments.

Apart from the common destination options described in Table 9.5, “Common options for destination drivers” the file() destination has the following options:

	Example 9.8. Using the file() driver
	destination d_file { file("/var/log/messages" ); };

	Example 9.9. Using the file() driver with macros in the file name and a template for the message
	destination d_file { file("/var/log/$YEAR.$MONTH.$DAY/messages" template("$HOUR:$MIN:$SEC $TZ $HOST [$LEVEL] $MSG $MSG\n") template_escape(no)); };

This driver sends messages to a named pipe like /dev/xconsole.

The pipe driver has a single required parameter, specifying the filename of the pipe to open.

Declaration:
pipe(filename);

	Note
	You have to create this pipe using mkfifo(1).

Apart from the common destination options described in Table 9.5, “Common options for destination drivers” the pipe() destination has the following options:

	Example 9.10. Using the pipe() driver
	destination d_pipe { pipe("/dev/xconsole"); };

This driver executes the specified program with the specified arguments and sends messages to the standard input (stdin) of the child.

The program() driver has a single required parameter, specifying a program name to start. The program is executed with the help of the current shell, so the command may include both file patterns and I/O redirection, they will be processed.

Declaration: 
program(command_to_run);

Note

Version 1.6 of syslog-ng executed the program once at startup, and kept it running until SIGHUP or exit. The reason was to prevent starting up a large number of programs for messages, which would have enabled an easy DoS attack. Versions 2.0 and later restart the program if it exits for reliability reasons. However it is not recommended to launch programs for single messages as that might easily cause a DoS for the system.

The program destination supports all common destination options described in Table 9.5, “Common options for destination drivers”.

Note that the message format does not include the priority and facility values by default (these values were automatically added in version 1.6.x of syslog-ng). To add these values, specify a template for the program destination, as shown in the following example.

	Example 9.11. Using the program() destination driver
	destination d_prog { program("/bin/script" template("<$PRI>$DATE $HOST $MSG\n"); };

This driver sends messages into an SQL database. Inserting the records into the database is performed by a separate thread. The syslog-ng application automatically performs the escaping required to insert the messages into the database. The table and value parameters can include macros (see Section 9.5, “Macros” for details).

	Note
	In order to use the sql() destination, syslog-ng Premium Edition must run in server mode. Typically, only the central syslog-ng Premium Edition server uses the sql() destination.

Declaration: 
sql(database_type host_parameters database_parameters [options]);

Note

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 Chapter 4, Installing syslog-ng. The sql() driver is currently not available for every platform that is supported by syslog-ng. For a list of platforms that support the sql() driver, visit http://www.balabit.com/network-security/syslog-ng/central-syslog-server/.

The common destination options described in Table 9.5, “Common options for destination drivers” are not available for the sql() destination. The sql() destination has the following options:

	Warning
	When using macros in table names, note that some databases limit the maximum allowed length of table names. Consult the documentation of the database for details.

Example 9.12. Using the sql() driver

The following example sends the log messages into a PostgreSQL database running on the logserver host. The messages are inserted into the logs database, the name of the table includes the exact date and the name of the host sending the messages. The syslog-ng application automatically creates the required tables and columns, if the user account used to connect to the database has the required privileges. destination d_sql { sql(type(pgsql) host("logserver") username("syslog-ng") password("password") database("logs") table("messages_${HOST}_${R_YEAR}${R_MONTH}${R_DAY}") columns("datetime", "host", "program", "pid", "message") values("$R_DATE", "$HOST", "$PROGRAM", "$PID", "$MSGONLY") indexes("datetime", "host", "program", "pid", "message")); };

9.2.5.1. Using the sql() driver with an Oracle database

The Oracle sql destination has some special aspects that are important to note.

• Apart from the syslog-ng PE packages, it requires the Oracle Instant Client package from Oracle. See the platform-specific installation instructions in Chapter 4, Installing syslog-ng for details.

• The hostname of the database server is set in the /etc/tnsnames.ora file, not in the host parameter of the sql() destination.

• As certain database versions limit the maximum length of table names, macros in the table names should be used with care.

• In the current version of syslog-ng PE, the types of database columns must be explicitly set for the Oracle destination. The column used to store the text part of the syslog messages should be able to store messages as long as the longest message permitted by syslog-ng, therefore it is usually recommended to use the varchar2 or clob column type. (The maximum length of the messages can be set using the log_msg_size() option.) See the following example for details.

Example 9.13. Using the sql() driver with an Oracle database

The following example sends the log messages into an Oracle database running on the logserver host, which must be set in the /etc/tnsnames.ora file. The messages are inserted into the LOGS database, the name of the table includes the exact date when the messages were sent. The syslog-ng application automatically creates the required tables and columns, if the user account used to connect to the database has the required privileges. destination d_sql { sql(type(oracle) username("syslog-ng") password("password") database("LOGS") table("msgs_${R_YEAR}${R_MONTH}${R_DAY}") columns("datetime varchar(16)", "host varchar(32)", "program varchar(32)", "pid varchar(8)", "message varchar2") values("$R_DATE", "$HOST", "$PROGRAM", "$PID", "$MSGONLY") indexes("datetime", "host", "program", "pid", "message")); }; The Oracle Instant Client retrieves the address of the database server from the /etc/tnsnames.ora file. Edit or create this file as needed for your configuration. A sample is provided below. LOGS = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP) (HOST = logserver) (PORT = 1521)) ) (CONNECT_DATA = (SERVICE_NAME = EXAMPLE.SERVICE) ) )

9.2.5.2. Using the sql() driver with a Microsoft SQL database

The freetds database driver can access Microsoft SQL (MSSQL) destinations. This driver has some special aspects that are important to note.

• The date format used by the MSSQL database must be explicitly set in the /etc/locales.conf file of the syslog-ng server. See the following example for details.

• As certain database versions limit the maximum length of table names, macros in the table names should be used with care.

• In the current version of syslog-ng PE, the types of database columns must be explicitly set for the MSSQL destination. The column used to store the text part of the syslog messages should be able to store messages as long as the longest message permitted by syslog-ng. The varchar column type can store maximum 4096 bytes-long messages. The maximum length of the messages can be set using the log_msg_size() option. See the following example for details.

• Remote access for SQL users must be explicitly enabled on the Microsoft Windows host running the Microsoft SQL Server. See Section 4.8, “Configuring Microsoft SQL Server to accept logs from syslog-ng” for details.

Example 9.14. Using the sql() driver with an MSSQL database

The following example sends the log messages into an MSSQL database running on the logserver host. The messages are inserted into the syslogng database, the name of the table includes the exact date when the messages were sent. The syslog-ng application automatically creates the required tables and columns, if the user account used to connect to the database has the required privileges. destination d_mssql { sql(type(freetds) host("logserver") port("1433") username("syslogng") password("syslogng") database("syslogng") table("msgs_${R_YEAR}${R_MONTH}${R_DAY}")columns("datetime varchar(16)", "host varchar(32)", "program varchar(32)", "pid varchar(8)", "message varchar(4096)") values("$R_DATE", "$HOST", "$PROGRAM", "$PID", "$MSGONLY") indexes("datetime", "host", "program", "pid", "message")); }; The date format used by the MSSQL database must be explicitly set in the /etc/locales.conf file of the syslog-ng server. Edit or create this file as needed for your configuration. A sample is provided below. [default] date = "%Y-%m-%d %H:%M:%S"

This driver sends messages to another host on the local intranet or internet using the UDP or TCP protocol. The tcp6() and udp6() drivers use the IPv6 network protocol.

Both drivers have a single required argument specifying the destination host address, where messages should be sent, and several optional parameters. Note that this differs from source drivers, where local bind address is implied, and none of the parameters are required.

The udp() and udp6() drivers automatically send multicast packets if a multicast destination address is specified. The tcp() and tcp6() drivers do not support multicasting.

Declaration:
tcp(host [options]);
udp(host [options]);
tcp6(host [options]);
udp6(host [options]);

Apart from the common destination options described in Table 9.5, “Common options for destination drivers” these destinations have the following options:

	Example 9.15. Using the tcp() driver
	destination d_tcp { tcp("10.1.2.3" port(1999); localport(999)); }; If name resolution is configured, the hostname of the target server can be used as well. destination d_tcp { tcp("target_host" port(1999); localport(999)); };

The tcp() and tcp6() drivers of the syslog-ng Premium Edition support disk-based buffering, and have the following option:

This driver sends messages to a unix socket in either SOCK_STREAM or SOCK_DGRAM mode.

Both drivers have a single required argument specifying the name of the socket to connect to.

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

Apart from the common destination options described in Table 9.5, “Common options for destination drivers” the unix-stream() and unix-dgram() destinations has the following options:

	Example 9.16. Using the unix-stream() driver
	destination d_unix_stream { unix-stream("/var/run/logs"); };

This driver writes messages to the terminal of a logged-in user.

The usertty() driver has a single required argument, specifying a username who should receive a copy of matching messages.

Declaration: 
  usertty(username);

The usertty() does not have any further options; nor can it use the common options available for other destinations..

	Note
	The usertty() destination does not support templates.

	Example 9.17. Using the usertty() driver
	destination d_usertty { usertty("root"); };