[role="xpack"]
[[community-id-processor]]
=== Community ID processor
++++
<titleabbrev>Community ID</titleabbrev>
++++

Computes the Community ID for network flow data as defined in the
https://github.com/corelight/community-id-spec[Community ID Specification].
You can use a community ID to correlate network events related to a single
flow.

The community ID processor reads network flow data from related
{ecs-ref}[Elastic Common Schema (ECS)] fields by default. If you use the ECS, no
configuration is required.

[[community-id-options]]
.Community ID Options
[options="header"]
|======
| Name               | Required | Default       | Description
| `source_ip`        | no       | `source.ip`   | Field containing the source IP address.
| `source_port`      | no       | `source.port` | Field containing the source port.
| `destination_ip`   | no       | `destination.ip` | Field containing the destination IP address.
| `destination_port` | no       | `destination.port` | Field containing the destination port.
| `iana_number` | no | `network.iana_number` | Field containing the IANA number.
| `icmp_type`        | no       | `icmp.type`   | Field containing the ICMP type.
| `icmp_code`        | no       | `icmp.code`   | Field containing the ICMP code.
| `transport`        | no       | `network.transport` | Field containing the transport protocol name or number.
Used only when the `iana_number` field is not present. The following protocol names are currently supported:
`ICMP`, `IGMP`, `TCP`, `UDP`, `GRE`, `ICMP IPv6`, `EIGRP`, `OSPF`, `PIM`, and `SCTP`.
| `target_field`     | no       | `network.community_id` | Output field for the community ID.
| `seed`             | no       | `0`           | Seed for the community ID hash. Must be between
0 and 65535 (inclusive). The seed can prevent hash collisions between network domains, such as
a staging and production network that use the same addressing scheme.
| `ignore_missing`   | no       | `true`        | If `true` and any required fields are missing,
the processor quietly exits without modifying the document.

include::common-options.asciidoc[]
|======

Here is an example definition of the community ID processor:

[source,js]
--------------------------------------------------
{
  "description" : "...",
  "processors" : [
    {
      "community_id": {
      }
    }
  ]
}
--------------------------------------------------
// NOTCONSOLE

When the above processor executes on the following document:

[source,js]
--------------------------------------------------
{
  "_source": {
    "source": {
      "ip": "123.124.125.126",
      "port": 12345
    },
    "destination": {
      "ip": "55.56.57.58",
      "port": 80
    },
    "network": {
      "transport": "TCP"
    }
  }
}
--------------------------------------------------
// NOTCONSOLE

It produces this result:

[source,js]
--------------------------------------------------
"_source" : {
  "destination" : {
    "port" : 80,
    "ip" : "55.56.57.58"
  },
  "source" : {
    "port" : 12345,
    "ip" : "123.124.125.126"
  },
  "network" : {
    "community_id" : "1:9qr9Z1LViXcNwtLVOHZ3CL8MlyM=",
    "transport" : "TCP"
  }
}
--------------------------------------------------
// NOTCONSOLE
