syslog-ng Open Source Edition 3.18 - Administration Guide

Looking up GeoIP2 data from IP addresses

The syslog-ng OSE application can lookup IP addresses from an offline GeoIP2 database, and make the retrieved data available in name-value pairs. Depending on the database used, you can access country code, longitude, and latitude information and so on.

The syslog-ng OSE application works with the Country and the City version of the GeoIP2 database, both free and the commercial editions. The syslog-ng OSE application works with the mmdb (GeoIP2) format of these databases. Other formats, like csv are not supported.

Referring to parts of the message as a macro

You can refer to the separated parts of the message using the key of the value as a macro. For example, if the message contains KEY1=value1,KEY2=value2, you can refer to the values as ${KEY1} and ${KEY2}.

For example if the default prefix (.geoip2) is used, you can determine the country code using ${.geoip2.country.iso_code}.

To look up all keys:

1. Install the mmdb-bin package.

   After installing this package, you will be able to use the mmdblookup command.

   NOTE: The name of the package depends on the Linux distribution. The package mentioned in this example is on Ubuntu.

2. Create a dump using the following command: mmdblookup --file GeoLite2-City.mmdb --ip <your-IP-address>

   The resulting dump file will contain the keys that you can use.

For a more complete list of keys, you can also check the GeoIP2 City and Country CSV Databases. However, note that the syslog-ng OSE application works with the mmdb (GeoIP2) format of these databases. Other formats, like csv are not supported.

Using the GeoIP2 parser

parser parser_name {
    geoip2(
        <macro-containing-the-IP-address-to-lookup>
        prefix()
        database("<path-to-geoip2-database-file>")
    );
};

In the following example, syslog-ng OSE retrieves the GeoIP2 data of the IP address contained in the ${HOST} field of the incoming message (assuming that in this case the ${HOST} field contains an IP address), and includes the data (prefixed with the geoip2 string) in the output JSON message.

@version: 3.11
@module geoip2

options {
    keep-hostname(yes);
};

source s_file {
    file("/tmp/input");
};

parser p_geoip2 {
    geoip2(
        "${HOST}",
        prefix( "geoip2." )
        database( "/usr/share/GeoIP2/GeoLiteCity.dat" )
    );
};

destination d_file {
    file(
        "/tmp/output"
        flags(syslog-protocol)
        template("$(format-json --scope core --key geoip2*)\n")
    );
};


log {
    source(s_file);
    parser(p_geoip2);
    destination(d_file);
};

For example, for the <38>2017-05-24T13:09:46 192.168.1.1 prg00000[1234]: test message message the output will look like:

<38>1 2017-05-24T13:09:46+02:00 192.168.1.1 prg00000 1234 - [meta sequenceId="3"] {"geoip2":{"subdivisions":{"0":{"names":{"en":"Budapest"},"iso_code":"BU","geoname_id":"3054638"}},"registered_country":{"names":{"en":"Hungary"},"iso_code":"HU","geoname_id":"719819"},"postal":{"code":"1063"},"location":{"time_zone":"Europe/Budapest","longitude":"19.070200","latitude":"47.510200","accuracy_radius":"5"},"country":{"names":{"en":"Hungary"},"iso_code":"HU","geoname_id":"719819"},"continent":{"names":{"en":"Europe"},"geoname_id":"6255148","code":"EU"},"city":{"names":{"en":"Budapest"},"geoname_id":"3054643"}},"PROGRAM":"prg00000","PRIORITY":"info","PID":"1234","MESSAGE":"test message","HOST":"192.168.1.1","FACILITY":"auth","DATE":"May 24 13:09:46"}

Transferring your logs to Elasticsearch using GeoIP2

If you are transferring your log messages into Elasticsearch, use the following rewrite rule to combine the longitude and latitude information into a single value (called geoip2.location), and set the mapping in Elasticsearch accordingly. Do not forget to include the rewrite in your log path. These examples assume that you used prefix("geoip2.") instead of the default for the geoip2 parser. For details on transferring your log messages to Elasticsearch, see elasticsearch2: Sending logs directly to Elasticsearch and Kibana 2.0 or higher.

rewrite r_geoip2 {
    set(
        "${geoip2.location.latitude},${geoip2.location.longitude}",
        value( "geoip2.location2" ),
        condition(not "${geoip2.location.latitude}" == "")
    );
};

In your Elasticsearch configuration, set the appropriate mappings:

{
   "mappings" : {
      "_default_" : {
         "properties" : {
            "geoip2" : {
               "properties" : {
                  "location2" : {
                     "type" : "geo_point"
                  }
               }
            }
         }
      }
   }
}