SNMP input plugin v1.2.6

• Plugin version: v1.2.6
• Released on: 2020-09-21
• Changelog

For other versions, see the overview list.

To learn more about Logstash, see the Logstash Reference.

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 SNMP input polls network devices using Simple Network Management Protocol (SNMP) to gather information related to the current state of the devices operation.

The SNMP input plugin supports SNMP v1, v2c, and v3 over UDP and TCP transport protocols.

This plugin already includes the IETF MIBs (management information bases) and these do not need to be imported.

Any other MIB will need to be manually imported to provide mapping of the numeric OIDs to MIB field names in the resulting event.

To import a MIB, the OSS libsmi library is required. libsmi is available and installable on most operating systems.

To import a MIB, you need to first convert the ASN.1 MIB file into a .dic file using the libsmi smidump command line utility.

Example (using RFC1213-MIB file)

$ smidump --level=1 -k -f python RFC1213-MIB > RFC1213-MIB.dic

Note that the resulting file as output by smidump must have the .dic extension.

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.

Use the get option to query for scalar values for the given OID(s). One or more OID(s) are specified as an array of strings of OID(s).

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

Example

input {
  snmp {
    get => ["1.3.6.1.2.1.1.1.0", "1.3.6.1.2.1.1.3.0", "1.3.6.1.2.1.1.5.0"]
    hosts => [{host => "udp:127.0.0.1/161" community => "public"}]
  }
}

The hosts option specifies the list of hosts to query the configured get and walk options.

Each host definition is a hash and must define the host key and value. host must use the format {tcp|udp}:{ip address}/{{port}}, for example host => "udp:127.0.0.1/161"

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

Each host definition can optionally include the following keys and values:

• community the community string, default is public.
• version 1, 2c or 3, default is 2c.
• retries is the number of retries in case of failure, default is 2.
• timeout is the timeout in milliseconds with a default value of 1000.

Specifying all hosts options

input {
  snmp {
    get => ["1.3.6.1.2.1.1.1.0"]
    hosts => [{host => "udp:127.0.0.1/161" community => "public" version => "2c"  retries => 2  timeout => 1000}]
  }
}

Specifying multiple hosts

input {
  snmp {
    get => ["1.3.6.1.2.1.1.1.0"]
    hosts => [{host => "udp:127.0.0.1/161" community => "public"}, {host => "udp:192.168.0.1/161" community => "private"}]
  }
}

Specifying IPv6 hosts

input {
  snmp {
    get => ["1.3.6.1.2.1.1.1.0"]
    hosts => [{host => "udp:[::1]/161" community => "public"}, {host => "udp:[2001:db8::2:1]/161" community => "private"}]
  }
}

The interval option specifies the polling interval in seconds.

• Value type is number
• Default value is 30

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 files or a file path to a single MIB .dic file.

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

This plugin includes the IETF MIBs. If you require other MIBs, you need to import them. See Importing MIBs.

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"

• 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"

• Value type is number
• Default value is 0

Use the walk option to retrieve the subtree of information for the given OID(s). One or more OID(s) are specified as an array of strings of OID(s).

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

Queries the subtree of information starting at the given OID(s).

Example

  snmp {
    walk => ["1.3.6.1.2.1.1"]
    hosts => [{host => "udp:127.0.0.1/161" community => "public"}]
  }
}

The tables option is used to query for tabular values for the given column OID(s).

Each table definition is a hash and must define the name key and value and the columns to return.

• Value type is array
• There is no default value for this setting
• Results are returned under a field using the table name

Specifying a single table

input {
  snmp {
    hosts => [{host => "udp:127.0.0.1/161" community => "public" version => "2c"  retries => 2  timeout => 1000}]
    tables => [ {"name" => "interfaces" "columns" => ["1.3.6.1.2.1.2.2.1.1", "1.3.6.1.2.1.2.2.1.2", "1.3.6.1.2.1.2.2.1.5"]} ]
  }
}

Specifying multiple tables

input {
  snmp {
    get => ["1.3.6.1.2.1.1.1.0"]
    tables => [ {"name" => "interfaces" "columns" => ["1.3.6.1.2.1.2.2.1.1", "1.3.6.1.2.1.2.2.1.2", "1.3.6.1.2.1.2.2.1.5"]}, {"name" => "ltmPoolStatTable" "columns" => ["1.3.6.1.4.1.3375.2.2.5.2.3.1.1", "1.3.6.1.4.1.3375.2.2.5.2.3.1.6"]} ]
  }
}

A single user can be configured and will be used for all defined SNMPv3 hosts. Multiple snmp input declarations will be needed if multiple SNMPv3 users are required. These options are required only if you are using SNMPv3.

The auth_pass option specifies the SNMPv3 authentication passphrase or password

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

The auth_protocol option specifies the SNMPv3 authentication protocol or type

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

The priv_pass option specifies the SNMPv3 encryption password

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

The priv_protocol option specifies the SNMPv3 privacy/encryption protocol.

• 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 security_name option specifies the SNMPv3 security name or user name

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

Specifying SNMPv3 settings

input {
  snmp {
    hosts => [{host => "udp:127.0.0.1/161" version => "3"}]
    get => ["1.3.6.1.2.1.1.1.0"]
    security_name => "mySecurityName"
    auth_protocol => "sha"
    auth_pass => "ShaPassword"
    priv_protocol => "aes"
    priv_pass => "AesPasword"
    security_level => "authPriv"
  }
}

Using both get and walk in the same poll cycle for each host(s)

input {
  snmp {
    get => ["1.3.6.1.2.1.1.1.0", "1.3.6.1.2.1.1.3.0", "1.3.6.1.2.1.1.5.0"]
    walk => ["1.3.6.1.2.1.1"]
    hosts => [{host => "udp:127.0.0.1/161" community => "public"}]
  }
}

Specifying all global options

input {
  snmp {
    get => ["1.3.6.1.2.1.1.1.0"]
    hosts => [{host => "udp:127.0.0.1/161"}]

    mib_paths => ["path/to/converted/mibfile.dic"]
    oid_root_skip => 0
    interval => 30
  }
}

All the polled host information is stored in the event @metadata:

• [@metadata][host_protocol] : udp or tcp
• [@metadata][host_address] : host address for example 127.0.0.1
• [@metadata][host_port] : host port (for example 161)
• [@metadata][host_community] : community string for example public

By default, a host field is added to the event with the [@metadata][host_address] value.

config :add_field, :validate => :hash, :default => { "host" => "%{[@metadata][host_address]}" }

You can customize the format and content of the host field by specifying an alternate add_field.

Example

input {
  snmp {
    get => ["1.3.6.1.2.1.1.1.0"]
    hosts => [{host => "udp:127.0.0.1/161"}]

    add_field => {host => "%{[@metadata][host_protocol]}:%{[@metadata][host_address]}/%{[@metadata][host_port]},%{[@metadata][host_community]}"}
  }
}

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 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 snmp inputs. Adding a named ID in this case will help in monitoring Logstash when using the monitoring APIs.

input {
  snmp {
    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.