How sources work

A source is where AxoSyslog receives log messages. Sources consist of one or more drivers, each defining where and how messages are received.

To define a source, add a source statement to the syslog-ng.conf configuration file using the following syntax:

   source <identifier> {
        source-driver(params); source-driver(params); ...
    };

Example: A simple source statement

The following source statement receives messages on the TCP port 1999 of the interface having the 10.1.2.3 IP address.

   source s_demo_tcp {
        network(ip(10.1.2.3) port(1999));
    };

Example: A source statement using two source drivers

The following source statement receives messages on the 1999 TCP port and the 1999 UDP port of the interface having the 10.1.2.3 IP address.

   source s_demo_two_drivers {
        network(ip(10.1.2.3) port(1999));
        network(ip(10.1.2.3) port(1999) transport("udp"));
    };

Example: Setting default priority and facility

If the message received by the source does not have a proper syslog header, you can use the default-facility() and default-priority() options to set the facility and priority of the messages. Note that these values are applied only to messages that do not set these parameters in their header.

   source headerless_messages { network(default-facility(syslog) default-priority(emerg)); };

Define a source only once. The same source can be used in several log paths. Duplicating sources causes AxoSyslog to open the source (TCP/IP port, file, and so on) more than once, which might cause problems. For example, include the /dev/log file source only in one source statement, and use this statement in more than one log path if needed.

To collect log messages on a specific platform, it is important to know how the native syslogd communicates on that platform. The following table summarizes the operation methods of syslogd on some of the tested platforms:

Communication methods used between the applications and syslogd

Each possible communication mechanism has a corresponding source driver in syslog-ng. For example, to open a unix socket with SOCK_DGRAM style communication use the driver unix-dgram. The same socket using the SOCK_STREAM style — as used under Linux — is called unix-stream.

Example: Source statement on a Linux based operating system

The following source statement collects the following log messages:

• internal(): Messages generated by syslog-ng.

• network(transport(“udp”)): Messages arriving to the 514/UDP port of any interface of the host.

• unix-dgram("/dev/log");: Messages arriving to the /dev/log socket.

   source s_demo {
        internal();
        network(transport("udp"));
        unix-dgram("/dev/log");
    };

Sources list

The following table lists the source drivers available in syslog-ng.

Source drivers available in syslog-ng