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

NOTE: To access longitude and latitude information, download the City version of the GeoIP2 database.

There are two types of GeoIP2 databases available.

  • GeoLite2 City:

    • free of charge

    • less accurate

  • GeoIP2 City:

    • has to be purchased

    • more accurate

Unzip the downloaded database (for example, to the /usr/share/GeoIP2/GeoIP2City.mmdb file). This path will be used later in the configuration.

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 ${}.

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 PE application works with the mmdb (GeoIP2) format of these databases. Other formats, like csv are not supported.

Using the GeoIP2 parser
parser parser_name {

In the following example, syslog-ng PE 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: 7.0
@module geoip2

options {

source s_file {

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 {

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

<38>1 2017-05-24T13:09:46+02:00 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":"","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 messages directly to Elasticsearch version 2.0 or higher (DEPRECATED).

rewrite r_geoip2 {
        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"
Options of geoip2 parsers

The geoip2 parser has the following options.

Synopsis: prefix()

Description: Insert a prefix before the name part of the parsed name-value pairs to help further processing. For example:

  • To insert the my-parsed-data. prefix, use the prefix(my-parsed-data.) option.

  • To refer to a particular data that has a prefix, use the prefix in the name of the macro, for example, ${} .

  • If you forward the parsed messages using the IETF-syslog protocol, you can insert all the parsed data into the SDATA part of the message using the prefix( option.

Names starting with a dot (for example, .example) are reserved for use by syslog-ng PE. If you use such a macro name as the name of a parsed value, it will attempt to replace the original value of the macro (note that only soft macros can be overwritten, see Hard versus soft macros for details). To avoid such problems, use a prefix when naming the parsed values, for example, prefix(my-parsed-data.)

For example, to insert the .geoip2 prefix, use the prefix(.geoip2) option. To refer to a particular data when using a prefix, use the prefix in the name of the macro, for example, ${geoip2.country_code} .

Synopsis: database()

Description: Path to the GeoIP2 database to use. This works with absolute and relative paths as well. Note that syslog-ng PE must have the required privileges to read this file. Do not modify or delete this file while syslog-ng PE is running, it can crash syslog-ng PE.