SNMP trap input plugin

• A component of the snmp integration plugin
• Integration version: v4.0.5
• Released on: 2025-01-06
• Changelog

For other versions, see the Versioned plugin docs.

For questions about the plugin, open a topic in the Discuss forums. For bugs or feature requests, open an issue in Github. For the list of Elastic supported plugins, please consult the Elastic Support Matrix.

The logstash-input-snmptrap plugin reads SNMP trap messages as events.

Resulting message field resembles:

{"agent_addr":"192.168.1.40", "generic_trap":6, "specific_trap":15511, "enterprise":"1.3.6.1.2.1.1.1", "variable_bindings":{"1.3.6.1.2.1.1.2.0":"test one", "1.3.6.1.2.1.1.1.0":"test two"}, "type":"V1TRAP", "community":"public", "version":1, "timestamp":1500}

Because SNMP data has specific field names based on OIDs, we recommend setting a target. The source host field changes based on ecs_compatibility.

This plugin also adds the trap PDU metadata to each event. The value is stored in the @metadata where it can be used by other plugins in the pipeline.

This plugin already includes the IETF MIBs (management information bases), and you do not need to import them. If you need additional MIBs, you need to import them. Check out Importing MIBs for info.

This plugin supports the following configuration options plus the Common options described later.

This plugin supports the following SNMPv3 authentication options.

Also see Common options for a list of options supported by all input plugins.

• Value type is array
• Default value is ["public"]

The SNMPv1 and SNMPv2c communities to listen for. To allow any community, set this config value to empty community => [].

Examples

Listen for public and guest communities

input {
  snmptrap {
    community => ["public", "guest"]
  }
}

Listen for all communities

input {
  snmptrap {
    community => []
  }
}

• Value type is string

• Supported values are:

  • disabled: does not use ECS-compatible field names (fields might be set at the root of the event)
  • v1, v8: avoids field names that might conflict with Elastic Common Schema (for example, the host field)

• Default value depends on which version of Logstash is running:

  • When Logstash provides a pipeline.ecs_compatibility setting, its value is used as the default
  • Otherwise, the default value is disabled.

Controls this plugin’s compatibility with the Elastic Common Schema (ECS).

• Value type is string
• Default value is "0.0.0.0"

The address to listen on.

• Value type is path
• There is no default value for this setting

The mib_paths option specifies the location of one or more imported MIB files. The value can be either a dir path containing the imported MIB (.dic, .yaml) files or a file path to a single MIB file.

• Value can be any of: default, ruby_snmp, dotted_string
• Default value is "default"

Defines the mapping textual representation of an OID in the Logstash event: * default translates every identifier, using the MIBs resolved names, separated by dots. Example: 1.3.6.1.2.1.1.2.0 is mapped as iso.org.dod.internet.mgmt.mib-2.system.sysObjectID.0 * ruby_snmp produces field names prefixed by the MIBs module name, followed by the latest resolved identifier name and unknowns values. Example: 1.3.6.1.2.1.1.2.0 is mapped as SNMPv2-MIB::sysObjectID.0. * dotted_string maps fields using the standard dotted string representation, Example: 1.3.6.1.2.1.1.2.0 is mapped as 1.3.6.1.2.1.1.2.0

• Value type is boolean
• Default value is false

Defines if the Logstash event fields values, which types are OID, are mapped using the configured OID textual representation set on the oid_mapping_format option.

• Value type is number
• Default value is 0

The oid_root_skip option specifies the number of OID root digits to ignore in the event field name. For example, in a numeric OID like "1.3.6.1.2.1.1.1.0" the first 5 digits could be ignored by setting oid_root_skip => 5 which would result in a field name "1.1.1.0". Similarly when a MIB is used an OID such "1.3.6.1.2.mib-2.system.sysDescr.0" would become "mib-2.system.sysDescr.0"

• You can use this setting or oid_path_length, but not both at the same time.
• Use this setting only if oid_mapping_format is set to default.

• Value type is number
• Default value is 0

The oid_path_length option specifies the number of OID root digits to retain in the event field name. For example, in a numeric OID like "1.3.6.1.2.1.1.1.0" the last 2 digits could be retained by setting oid_path_length => 2 which would result in a field name "1.0". Similarly when a MIB is used an OID such "1.3.6.1.2.mib-2.system.sysDescr.0" would become "sysDescr.0"

• You can use this setting or oid_root_skip, but not both at the same time.
• Use this setting only if oid_mapping_format is set to default.

• Value type is number
• Default value is 1062

The port to listen on. Remember that ports less than 1024 (privileged ports) may require root to use. hence the default of 1062.

• Value type is string
• Allowed values are: tcp, udp
• Default value is ["udp"]

The supported transport protocols to listen on.

SNMP was originally designed for use with UDP as transport protocol and is the official recommendation. TCP is an optional transport mapping and can be enabled if needed. For more details on SNMP over TCP, please refer to the RFC-3430.

• Value type is string
• Allowed values are: 1, 2c, 3
• Default value is ["1", "2c"]

The supported SNMP protocol versions to listen on. SNMP messages for versions that are either unsupported and/or disabled are automatically discarded.

• Value type is string
• There is no default value for this setting

The name of the field under which SNMP payloads are assigned. If not specified data will be stored in the root of the event.

Setting a target is recommended when ecs_compatibility is enabled.

• Value type is number
• Default value is 75% of the number of CPU cores

The number of threads to use for processing the received SNMP trap messages.

• Value type is boolean
• Default value is true

This plugin provides all IETF MIBs (management information bases), publicly available in the libsmi version 0.5.0. When enabled, it automatically loads the bundled MIBs and provides mapping of the numeric OIDs to MIB field names in the resulting event.

• Value type is string
• There is no default value for this setting.

directory of YAML MIB maps (same format ruby-snmp uses)

A single user can be configured. Multiple snmptrap input declarations will be needed if multiple SNMPv3 users are required. These options are required only if you are using SNMPv3.

• Value type is password
• There is no default value for this setting

The auth_pass option specifies the SNMPv3 authentication passphrase or password.

The auth_protocol option specifies the SNMPv3 authentication protocol or type

• Value can be any of: md5, sha, sha2, hmac128sha224, hmac192sha256, hmac256sha384, hmac384sha512
• Note that sha2 and hmac192sha256 are equivalent
• There is no default value for this setting

• Value type is password
• There is no default value for this setting

The priv_pass option specifies the SNMPv3 encryption password.

• Value can be any of: des, 3des, aes, aes128, aes192, aes256
• Note that aes and aes128 are equivalent
• There is no default value for this setting

The priv_protocol option specifies the SNMPv3 privacy/encryption protocol.

• Value can be any of: noAuthNoPriv, authNoPriv, authPriv
• There is no default value for this setting

The security_level option specifies the SNMPv3 security level between Authentication, No Privacy; Authentication, Privacy; or no Authentication, no Privacy.

• Value type is string
• There is no default value for this setting

The security_name option specifies the SNMPv3 security name or user name.

Specifying SNMPv3 traps settings

input {
  snmptrap {
    supported_versions => ['3']
    security_name => "mySecurityName"
    auth_protocol => "sha"
    auth_pass => "ShaPassword"
    priv_protocol => "aes"
    priv_pass => "AesPasword"
    security_level => "authPriv"
  }
}

These configuration options are supported by all input plugins:

• Value type is hash
• Default value is {}

Add a field to an event

• Value type is codec
• Default value is "plain"

The codec used for input data. Input codecs are a convenient method for decoding your data before it enters the input, without needing a separate filter in your Logstash pipeline.

• Value type is boolean
• Default value is true

Disable or enable metric logging for this specific plugin instance by default we record all the metrics we can, but you can disable metrics collection for a specific plugin.

• Value type is string
• There is no default value for this setting.

Add a unique ID to the plugin configuration. If no ID is specified, Logstash will generate one. It is strongly recommended to set this ID in your configuration. This is particularly useful when you have two or more plugins of the same type, for example, if you have 2 snmptrap inputs. Adding a named ID in this case will help in monitoring Logstash when using the monitoring APIs.

input {
  snmptrap {
    id => "my_plugin_id"
  }
}

• Value type is array
• There is no default value for this setting.

Add any number of arbitrary tags to your event.

This can help with processing later.

• Value type is string
• There is no default value for this setting.

Add a type field to all events handled by this input.

Types are used mainly for filter activation.

The type is stored as part of the event itself, so you can also use the type to search for it in Kibana.

If you try to set a type on an event that already has one (for example when you send an event from a shipper to an indexer) then a new input will not override the existing type. A type set at the shipper stays with that event for its life even when sent to another Logstash server.