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Netflow Input Plugin

plugins/inputs/netflow/README.md

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Netflow Input Plugin

This service plugin acts as a collector for Netflow v5, Netflow v9 and IPFIX flow information. The Layer 4 protocol numbers are gathered from the official IANA assignments. The internal field mappings for Netflow v5 fields are defined according to Cisco's Netflow v5 documentation, Netflow v9 fields are defined according to Cisco's Netflow v9 documentation and the ASA extensions. Definitions for IPFIX are according to IANA assignment document.

⭐ Telegraf v1.25.0 🏷️ network 💻 all

Service Input <!-- @/docs/includes/service_input.md -->

This plugin is a service input. Normal plugins gather metrics determined by the interval setting. Service plugins start a service to listen and wait for metrics or events to occur. Service plugins have two key differences from normal plugins:

  1. The global or plugin specific interval setting may not apply
  2. The CLI options of --test, --test-wait, and --once may not produce output for this plugin

Global configuration options <!-- @/docs/includes/plugin_config.md -->

Plugins support additional global and plugin configuration settings for tasks such as modifying metrics, tags, and fields, creating aliases, and configuring plugin ordering. See CONFIGURATION.md for more details.

Configuration

toml
# Netflow v5, Netflow v9 and IPFIX collector
[[inputs.netflow]]
  ## Address to listen for netflow,ipfix or sflow packets.
  ##   example: service_address = "udp://:2055"
  ##            service_address = "udp4://:2055"
  ##            service_address = "udp6://:2055"
  service_address = "udp://:2055"

  ## Set the size of the operating system's receive buffer.
  ##   example: read_buffer_size = "64KiB"
  ## Uses the system's default if not set.
  # read_buffer_size = ""

  ## Protocol version to use for decoding.
  ## Available options are
  ##   "ipfix"      -- IPFIX / Netflow v10 protocol (also works for Netflow v9)
  ##   "netflow v5" -- Netflow v5 protocol
  ##   "netflow v9" -- Netflow v9 protocol (also works for IPFIX)
  ##   "sflow v5"   -- sFlow v5 protocol
  # protocol = "ipfix"

  ## Private Enterprise Numbers (PEN) mappings for decoding
  ## This option allows to specify vendor-specific mapping files to use during
  ## decoding.
  # private_enterprise_number_files = []

  ## Log incoming packets for tracing issues
  # log_level = "trace"

Private Enterprise Number mapping

Using the private_enterprise_number_files option you can specify mappings for vendor-specific element-IDs with a PEN specification. The mapping has to be a comma-separated-file (CSV) containing the element's ID, its name and the data-type. A comma (,) is used as separator and comments are allowed using the hash (#) prefix. The element ID has the form <pen-number>.<element-id>, the name has to be a valid field-name and data-type denotes the mapping of the raw-byte value to the field's type. For example

csv
# PEN.ID, name, data type
35632.349,in_src_osi_sap,hex
35632.471,nprobe_ipv4_address,ip
35632.1028,protocol_ntop,string
35632.1036,l4_srv_port,uint

specify four elements (349, 471, 1028 and 1036) for PEN 35632 (ntop) with the corresponding name and data-type.

Currently the following data-types are supported:

  • bool TruthValue according to RFC5101
  • int signed integer with 8, 16, 32 or 64 bit
  • uint unsigned integer with 8, 16, 32 or 64 bit
  • float32 double-precision floating-point number (32 bit)
  • float64 double-precision floating-point number (64 bit)
  • hex hex-encoding of the raw byte sequence with 0x prefix
  • string string interpretation of the raw byte sequence
  • mac MAC address
  • ip IPv4 or IPv6 address
  • proto mapping of layer-4 protocol numbers to names

Troubleshooting

Error template not found warnings

Those warnings usually occur in cases where Telegraf is restarted or reloaded while the flow-device is already streaming data. As background, the Netflow and IPFIX protocols rely on templates sent by the flow-device to decode fields. Without those templates, it is not clear what the data-type and size of the payload is and this makes it impossible to correctly interpret the data. However, templates are sent by the flow-device, usually at the start of streaming and in regular intervals (configurable in the device) and Telegraf has no means to trigger sending of the templates. Therefore, we need to skip the packets until the templates are resent by the device.

Metrics are missing at the output

The metrics produced by this plugin are not tagged in a connection specific manner, therefore outputs relying on unique series key (e.g. InfluxDB) require the metrics to contain tags for the protocol, the connection source and the connection destination. Otherwise, metrics might be overwritten and are thus missing.

The required tagging can be achieved using the converter processor

toml
[[processors.converter]]
  [processors.converter.fields]
    tag = ["protocol", "src", "src_port", "dst", "dst_port"]

Please be careful as this will produce metrics with high cardinality!

Metrics

Metrics depend on the format used as well as on the information provided by the exporter. Furthermore, proprietary information might be sent requiring further decoding information. Most exporters should provide at least the following information

  • netflow
    • tags:
      • source (IP of the exporter sending the data)
      • version (flow protocol version)
    • fields:
      • src (IP address, address of the source of the packets)
      • src_mask (uint64, mask for the IP address in bits)
      • dst (IP address, address of the destination of the packets)
      • dst_mask (uint64, mask for the IP address in bits)
      • src_port (uint64, source port)
      • dst_port (uint64, destination port)
      • protocol (string, Layer 4 protocol name)
      • in_bytes (uint64, number of incoming bytes)
      • in_packets (uint64, number of incoming packets)
      • tcp_flags (string, TCP flags for the flow)

Example Output

The specific fields vary for the different protocol versions, here are some examples

IPFIX

text
netflow,source=127.0.0.1,version=IPFIX protocol="tcp",vlan_src=0u,src_tos="0x00",flow_end_ms=1666345513807u,src="192.168.119.100",dst="44.233.90.52",src_port=51008u,total_bytes_exported=0u,flow_end_reason="end of flow",flow_start_ms=1666345513807u,in_total_bytes=52u,in_total_packets=1u,dst_port=443u
netflow,source=127.0.0.1,version=IPFIX src_tos="0x00",src_port=54330u,rev_total_bytes_exported=0u,last_switched=9u,vlan_src=0u,flow_start_ms=1666345513807u,in_total_packets=1u,flow_end_reason="end of flow",flow_end_ms=1666345513816u,in_total_bytes=40u,dst_port=443u,src="192.168.119.100",dst="104.17.240.92",total_bytes_exported=0u,protocol="tcp"
netflow,source=127.0.0.1,version=IPFIX flow_start_ms=1666345513807u,flow_end_ms=1666345513977u,src="192.168.119.100",dst_port=443u,total_bytes_exported=0u,last_switched=170u,src_tos="0x00",in_total_bytes=40u,dst="44.233.90.52",src_port=51024u,protocol="tcp",flow_end_reason="end of flow",in_total_packets=1u,rev_total_bytes_exported=0u,vlan_src=0u
netflow,source=127.0.0.1,version=IPFIX src_port=58246u,total_bytes_exported=1u,flow_start_ms=1666345513806u,flow_end_ms=1666345513806u,in_total_bytes=156u,src="192.168.119.100",rev_total_bytes_exported=0u,last_switched=0u,flow_end_reason="forced end",dst="192.168.119.17",dst_port=53u,protocol="udp",in_total_packets=2u,vlan_src=0u,src_tos="0x00"
netflow,source=127.0.0.1,version=IPFIX protocol="udp",vlan_src=0u,src_port=58879u,dst_port=53u,flow_end_ms=1666345513832u,src_tos="0x00",src="192.168.119.100",total_bytes_exported=1u,rev_total_bytes_exported=0u,flow_end_reason="forced end",last_switched=33u,in_total_bytes=221u,in_total_packets=2u,flow_start_ms=1666345513799u,dst="192.168.119.17"

Netflow v5

text
netflow,source=127.0.0.1,version=NetFlowV5 protocol="tcp",src="140.82.121.3",src_port=443u,dst="192.168.119.100",dst_port=55516u,flows=8u,in_bytes=87477u,in_packets=78u,first_switched=86400660u,last_switched=86403316u,tcp_flags="...PA...",engine_type="19",engine_id="0x56",sys_uptime=90003000u,src_tos="0x00",bgp_src_as=0u,bgp_dst_as=0u,src_mask=0u,dst_mask=0u,in_snmp=0u,out_snmp=0u,next_hop="0.0.0.0",seq_number=0u,sampling_interval=0u
netflow,source=127.0.0.1,version=NetFlowV5 protocol="tcp",src="140.82.121.6",src_port=443u,dst="192.168.119.100",dst_port=36408u,flows=8u,in_bytes=5009u,in_packets=21u,first_switched=86400447u,last_switched=86403267u,tcp_flags="...PA...",engine_type="19",engine_id="0x56",sys_uptime=90003000u,src_tos="0x00",bgp_src_as=0u,bgp_dst_as=0u,src_mask=0u,dst_mask=0u,in_snmp=0u,out_snmp=0u,next_hop="0.0.0.0",seq_number=0u,sampling_interval=0u
netflow,source=127.0.0.1,version=NetFlowV5 protocol="tcp",src="140.82.112.22",src_port=443u,dst="192.168.119.100",dst_port=39638u,flows=8u,in_bytes=925u,in_packets=6u,first_switched=86400324u,last_switched=86403214u,tcp_flags="...PA...",engine_type="19",engine_id="0x56",sys_uptime=90003000u,src_tos="0x00",bgp_src_as=0u,bgp_dst_as=0u,src_mask=0u,dst_mask=0u,in_snmp=0u,out_snmp=0u,next_hop="0.0.0.0",seq_number=0u,sampling_interval=0u
netflow,source=127.0.0.1,version=NetFlowV5 protocol="tcp",src="140.82.114.26",src_port=443u,dst="192.168.119.100",dst_port=49398u,flows=8u,in_bytes=250u,in_packets=2u,first_switched=86403131u,last_switched=86403362u,tcp_flags="...PA...",engine_type="19",engine_id="0x56",sys_uptime=90003000u,src_tos="0x00",bgp_src_as=0u,bgp_dst_as=0u,src_mask=0u,dst_mask=0u,in_snmp=0u,out_snmp=0u,next_hop="0.0.0.0",seq_number=0u,sampling_interval=0u
netflow,source=127.0.0.1,version=NetFlowV5 protocol="tcp",src="192.168.119.100",src_port=55516u,dst="140.82.121.3",dst_port=443u,flows=8u,in_bytes=4969u,in_packets=37u,first_switched=86400652u,last_switched=86403269u,tcp_flags="...PA...",engine_type="19",engine_id="0x56",sys_uptime=90003000u,src_tos="0x00",bgp_src_as=0u,bgp_dst_as=0u,src_mask=0u,dst_mask=0u,in_snmp=0u,out_snmp=0u,next_hop="0.0.0.0",seq_number=0u,sampling_interval=0u
netflow,source=127.0.0.1,version=NetFlowV5 protocol="tcp",src="192.168.119.100",src_port=36408u,dst="140.82.121.6",dst_port=443u,flows=8u,in_bytes=2736u,in_packets=21u,first_switched=86400438u,last_switched=86403258u,tcp_flags="...PA...",engine_type="19",engine_id="0x56",sys_uptime=90003000u,src_tos="0x00",bgp_src_as=0u,bgp_dst_as=0u,src_mask=0u,dst_mask=0u,in_snmp=0u,out_snmp=0u,next_hop="0.0.0.0",seq_number=0u,sampling_interval=0u
netflow,source=127.0.0.1,version=NetFlowV5 protocol="tcp",src="192.168.119.100",src_port=39638u,dst="140.82.112.22",dst_port=443u,flows=8u,in_bytes=1560u,in_packets=6u,first_switched=86400225u,last_switched=86403255u,tcp_flags="...PA...",engine_type="19",engine_id="0x56",sys_uptime=90003000u,src_tos="0x00",bgp_src_as=0u,bgp_dst_as=0u,src_mask=0u,dst_mask=0u,in_snmp=0u,out_snmp=0u,next_hop="0.0.0.0",seq_number=0u,sampling_interval=0u
netflow,source=127.0.0.1,version=NetFlowV5 protocol="tcp",src="192.168.119.100",src_port=49398u,dst="140.82.114.26",dst_port=443u,flows=8u,in_bytes=697u,in_packets=4u,first_switched=86403030u,last_switched=86403362u,tcp_flags="...PA...",engine_type="19",engine_id="0x56",sys_uptime=90003000u,src_tos="0x00",bgp_src_as=0u,bgp_dst_as=0u,src_mask=0u,dst_mask=0u,in_snmp=0u,out_snmp=0u,next_hop="0.0.0.0",seq_number=0u,sampling_interval=0u

Netflow v9

text
netflow,source=127.0.0.1,version=NetFlowV9 protocol="tcp",src="140.82.121.3",src_port=443u,dst="192.168.119.100",dst_port=55516u,in_bytes=87477u,in_packets=78u,flow_start_ms=1666350478660u,flow_end_ms=1666350481316u,tcp_flags="...PA...",engine_type="17",engine_id="0x01",icmp_type=0u,icmp_code=0u,fwd_status="unknown",fwd_reason="unknown",src_tos="0x00"
netflow,source=127.0.0.1,version=NetFlowV9 protocol="tcp",src="140.82.121.6",src_port=443u,dst="192.168.119.100",dst_port=36408u,in_bytes=5009u,in_packets=21u,flow_start_ms=1666350478447u,flow_end_ms=1666350481267u,tcp_flags="...PA...",engine_type="17",engine_id="0x01",icmp_type=0u,icmp_code=0u,fwd_status="unknown",fwd_reason="unknown",src_tos="0x00"
netflow,source=127.0.0.1,version=NetFlowV9 protocol="tcp",src="140.82.112.22",src_port=443u,dst="192.168.119.100",dst_port=39638u,in_bytes=925u,in_packets=6u,flow_start_ms=1666350478324u,flow_end_ms=1666350481214u,tcp_flags="...PA...",engine_type="17",engine_id="0x01",icmp_type=0u,icmp_code=0u,fwd_status="unknown",fwd_reason="unknown",src_tos="0x00"
netflow,source=127.0.0.1,version=NetFlowV9 protocol="tcp",src="140.82.114.26",src_port=443u,dst="192.168.119.100",dst_port=49398u,in_bytes=250u,in_packets=2u,flow_start_ms=1666350481131u,flow_end_ms=1666350481362u,tcp_flags="...PA...",engine_type="17",engine_id="0x01",icmp_type=0u,icmp_code=0u,fwd_status="unknown",fwd_reason="unknown",src_tos="0x00"
netflow,source=127.0.0.1,version=NetFlowV9 protocol="tcp",src="192.168.119.100",src_port=55516u,dst="140.82.121.3",dst_port=443u,in_bytes=4969u,in_packets=37u,flow_start_ms=1666350478652u,flow_end_ms=1666350481269u,tcp_flags="...PA...",engine_type="17",engine_id="0x01",icmp_type=0u,icmp_code=0u,fwd_status="unknown",fwd_reason="unknown",src_tos="0x00"
netflow,source=127.0.0.1,version=NetFlowV9 protocol="tcp",src="192.168.119.100",src_port=36408u,dst="140.82.121.6",dst_port=443u,in_bytes=2736u,in_packets=21u,flow_start_ms=1666350478438u,flow_end_ms=1666350481258u,tcp_flags="...PA...",engine_type="17",engine_id="0x01",icmp_type=0u,icmp_code=0u,fwd_status="unknown",fwd_reason="unknown",src_tos="0x00"
netflow,source=127.0.0.1,version=NetFlowV9 protocol="tcp",src="192.168.119.100",src_port=39638u,dst="140.82.112.22",dst_port=443u,in_bytes=1560u,in_packets=6u,flow_start_ms=1666350478225u,flow_end_ms=1666350481255u,tcp_flags="...PA...",engine_type="17",engine_id="0x01",icmp_type=0u,icmp_code=0u,fwd_status="unknown",fwd_reason="unknown",src_tos="0x00"
netflow,source=127.0.0.1,version=NetFlowV9 protocol="tcp",src="192.168.119.100",src_port=49398u,dst="140.82.114.26",dst_port=443u,in_bytes=697u,in_packets=4u,flow_start_ms=1666350481030u,flow_end_ms=1666350481362u,tcp_flags="...PA...",engine_type="17",engine_id="0x01",icmp_type=0u,icmp_code=0u,fwd_status="unknown",fwd_reason="unknown",src_tos="0x00"

sFlow v5

text
netflow,source=127.0.0.1,version=sFlowV5 out_errors=0i,out_bytes=3946i,status="up",in_unknown_protocol=4294967295i,out_unicast_packets_total=29i,agent_subid=100000i,interface_type=6i,in_unicast_packets_total=28i,out_dropped_packets=0i,in_bytes=3910i,in_broadcast_packets_total=4294967295i,ip_version="IPv4",agent_ip="192.168.119.184",in_snmp=3i,in_errors=0i,promiscuous=0i,interface=3i,in_mcast_packets_total=4294967295i,in_dropped_packets=0i,sys_uptime=12414i,seq_number=2i,speed=1000000000i,out_mcast_packets_total=4294967295i,out_broadcast_packets_total=4294967295i 12414000000
netflow,source=127.0.0.1,version=sFlowV5 sys_uptime=17214i,agent_ip="192.168.119.184",agent_subid=100000i,seq_number=2i,in_phy_interface=1i,ip_version="IPv4" 17214000000
netflow,source=127.0.0.1,version=sFlowV5 in_errors=0i,out_unicast_packets_total=36i,interface=3i,in_broadcast_packets_total=4294967295i,ip_version="IPv4",speed=1000000000i,out_bytes=4408i,out_mcast_packets_total=4294967295i,status="up",in_snmp=3i,in_mcast_packets_total=4294967295i,out_broadcast_packets_total=4294967295i,promiscuous=0i,in_bytes=5568i,out_dropped_packets=0i,sys_uptime=22014i,agent_subid=100000i,in_unknown_protocol=4294967295i,interface_type=6i,in_dropped_packets=0i,in_unicast_packets_total=37i,out_errors=0i,agent_ip="192.168.119.184",seq_number=3i 22014000000