NetFlow input

Use the netflow input to read NetFlow and IPFIX exported flows and options records over UDP.

This input supports NetFlow versions 1, 5, 6, 7, 8 and 9, as well as IPFIX. For NetFlow versions older than 9, fields are mapped automatically to NetFlow v9.

Example configuration:

filebeat.inputs:
- type: netflow
  max_message_size: 10KiB
  host: "0.0.0.0:2055"
  protocols: [ v5, v9, ipfix ]
  expiration_timeout: 30m
  queue_size: 8192
  custom_definitions:
  - path/to/fields.yml
  detect_sequence_reset: true

The netflow input supports the following configuration options plus the Common options described later.

The maximum size of the message received over UDP. The default is 10KiB.

The host and UDP port to listen on for event streams.

The network type. Acceptable values are: "udp" (default), "udp4", "udp6"

The size of the read buffer on the UDP socket. If not specified the default from the operating system will be used.

The read and write timeout for socket operations. The default is 5m.

List of enabled protocols. Valid values are v1, v5, v6, v7, v8, v9 and ipfix.

The time before an idle session or unused template is expired. Only applicable to v9 and IPFIX protocols. A value of zero disables expiration.

This option allows v9 and ipfix templates to be shared within a session without reference to the origin of the template.

Note that setting this to true is not recommended as it can result in the wrong template being applied under certain conditions, but it may be required for some systems.

The maximum number of packets that can be queued for processing. Use this setting to avoid packet-loss when dealing with occasional bursts of traffic.

The number of workers to read and decode concurrently netflow packets. Default is 1. Note that in order to maximize the performance gains of multiple workers it is advised to switch the output to throughput preset (link).

A list of paths to field definitions YAML files. These allow to update the NetFlow/IPFIX fields with vendor extensions and to override existing fields.

The expected format is the same as used by Logstash’s NetFlow codec ipfix_definitions and netflow_definitions. Filebeat will detect which of the two formats is used.

NetFlow format example:

id:
- default length in bytes
- :name
id:
- :uintN or :intN: or :ip4_addr or :ip6_addr or :mac_addr or :string
- :name
id:
- :skip

Where id is the numeric field ID.

The IPFIX format similar, but grouped by Private Enterprise Number (PEN):

pen1:
  id:
  - :uintN or :ip4_addr or :ip6_addr or :mac_addr or :string
  - :name
  id:
  - :skip
pen2:
  id:
  - :octetarray
  - :name

Note that fields are shared between NetFlow V9 and IPFIX. Changes to IPFIX PEN zero are equivalent to changes to NetFlow fields.

Flag controlling whether Filebeat should monitor sequence numbers in the Netflow packets to detect an Exporting Process reset. When this condition is detected, record templates for the given exporter will be dropped. This will cause flow loss until the exporter provides new templates. If set to false, Filebeat will ignore sequence numbers, which can cause some invalid flows if the exporter process is reset. This option is only applicable to Netflow V9 and IPFIX. Default is true.

A list of CIDR ranges describing the IP addresses that you consider internal. This is used in determining the values of source.locality, destination.locality, and flow.locality. The values can be either a CIDR value or one of the named ranges supported by the network condition. The default value is [private] which classifies RFC 1918 (IPv4) and RFC 4193 (IPv6) addresses as internal.

The following configuration options are supported by all inputs.

Use the enabled option to enable and disable inputs. By default, enabled is set to true.

A list of tags that Filebeat includes in the tags field of each published event. Tags make it easy to select specific events in Kibana or apply conditional filtering in Logstash. These tags will be appended to the list of tags specified in the general configuration.

Example:

filebeat.inputs:
- type: netflow
  . . .
  tags: ["json"]

Optional fields that you can specify to add additional information to the output. For example, you might add fields that you can use for filtering log data. Fields can be scalar values, arrays, dictionaries, or any nested combination of these. By default, the fields that you specify here will be grouped under a fields sub-dictionary in the output document. To store the custom fields as top-level fields, set the fields_under_root option to true. If a duplicate field is declared in the general configuration, then its value will be overwritten by the value declared here.

filebeat.inputs:
- type: netflow
  . . .
  fields:
    app_id: query_engine_12

If this option is set to true, the custom fields are stored as top-level fields in the output document instead of being grouped under a fields sub-dictionary. If the custom field names conflict with other field names added by Filebeat, then the custom fields overwrite the other fields.

A list of processors to apply to the input data.

See Processors for information about specifying processors in your config.

The ingest pipeline ID to set for the events generated by this input.

If this option is set to true, fields with null values will be published in the output document. By default, keep_null is set to false.

If present, this formatted string overrides the index for events from this input (for elasticsearch outputs), or sets the raw_index field of the event’s metadata (for other outputs). This string can only refer to the agent name and version and the event timestamp; for access to dynamic fields, use output.elasticsearch.index or a processor.

Example value: "%{[agent.name]}-myindex-%{+yyyy.MM.dd}" might expand to "filebeat-myindex-2019.11.01".

By default, all events contain host.name. This option can be set to true to disable the addition of this field to all events. The default value is false.

This input exposes metrics under the HTTP monitoring endpoint. These metrics are exposed under the /inputs/ path. They can be used to observe the activity of the input.

You must assign a unique id to the input to expose metrics.

Histogram metrics are aggregated over the previous 1024 events.