Use Splunk Stream to ingest Netflow and IPFIX data
NetFlow and IP Flow Information Export (IPFIX) are protocols that collect flow data from network devices. Use Splunk Stream to ingest Netflow and IPFIX data. You can use Splunk Stream to ingest Netflow and IPFIX data. Splunk Stream supports flow data sent over the UDP protocol.
Configure indexers
Enable the Http_input
receiver on your Splunk platform deployment's indexers:
- Navigate to your
splunk_httpinput
directory.- For a single instance deployment navigate to
$SPLUNK_HOME/etc/apps/splunk_httpinput/local/
- For a distributed deployment navigate to
$SPLUNK_HOME/etc/master-app/splunk_httpinput/local/
- For a single instance deployment navigate to
- Create an
inputs.conf
file, if one does not already exist. - Open
inputs.conf
and add stanzas to enable receiving. For example:[http] disabled = 0 port = 8088 dedicatedIoThreads = 8 [http://streamfwd] disabled = 0 index=main token = 152B6F2B-8A21-4850-A444-CB0646FD88BE indexes=_internal,main
- Save your changes and exit.
- Restart your Splunk platform deployment.
(Optional) Modify Splunk Stream Forwarder and push to clustered indexers
For Splunk platform deployments that use indexer clustering, modify the Splunk Stream Forwarder:
- Navigate to
Splunk_TA_stream/default
on your Splunk platform deployment. - Remove the following files, if they are present:
inputs.conf
inputs.conf.spec
.
- Push the modified
Splunk_TA_stream
to all indexers in your Splunk platform deployment.
Configure the Independent Stream Forwarder
Configure the Independent Stream Forwarder on your Splunk platform deployment.
- On your deployment's Independent Stream Forwarder, navigate to
streamfwd.conf
. - Open
streamfwd.conf
and enable forwarding.[streamfwd] httpEventCollectorToken = 152B6F2B-8A21-4850-A444-CB0646FD88BE #(Match this with the token in the indexers) ipAddr = 0.0.0.0 processingThreads = 4
- In your
streamfwd.conf
file, add your deployment's NetFlow configuration.[streamfwd] httpEventCollectorToken = <GUID> indexer.0.uri= <HEC VIP> netflowReceiver.0.port = 9996 netflowReceiver.0.decoder = netflow netflowReceiver.0.ip = 172.18.1.4 netflowReceiver.0.decodingThreads = 16
- Save your changes.
- Restart your Splunk platform deployment.
- Navigate to your independent Stream Forwarder's
etc/sysctl.conf
directory. - Adjust your kernel settings to increase buffer sizes for high-volume packet capture.
sysctl -w net.core.rmem_default=33554432 sysctl -w net.core.rmem_max=33554432 sysctl -w net.core.netdev_max_backlog=10000
- Reload the settings:
/sbin/sysctl -p
- Restart the
streamfwd
service:Service streamfwd restart
Configure search heads
- Log in to the search head where the Splunk App for Stream is installed.
- Navigate to the Splunk App for Stream, then click Configuration > Distributed Forwarder Management.
- Click Create New Group.
- Enter a name. For example, INFRA_NETFLOW.
- Enter a description.
- Click Next.
- Enter the regular expression to match the
streamforwarder_id
or hostname of the "streamfwd" collectors that should participate in this group rule. Click Next. - Do not select any options. Click Finish.
- Navigate to the Splunk App for Stream, then click Configuration > Configure Streams.
- Click New Stream > Metadata.
- Enter Name as INFRA_NETFLOW.
- Select NetFlow as the protocol.
- Enter a description then click Next.
- Select No in the Aggregation box then click Next.
- (Optional) Deselect any fields that do not apply to your use case then click Next.
- (Optional) Develop filters to reduce noise from high traffic devices then click Next.
- Select the index for this collection and click Enable then click Next.
- Select only the
INFRA_NETFLOW
group andCreate_Stream
. - Configure your NetFlow generator to send records to the new
streamfwd
. - Validate your results by searching the configured index on your Splunk platform deployment.
The NetFlow option works for NetFlow, sFlow, jFlow, and IPFIX protocols.
Configure Flow collector
Splunk Stream supports flow protocol data ingestion from network devices. If you have switches, routers, firewalls. or other elements that generate flow protocol data such as NetFlow and sFlow, you can configure your Splunk Stream Forwarder or Splunk Independent Stream Forwarder to support flow data ingestion.
Supported flow protocols
Stream supports collection of these flow protocols:
- NetFlow version 5, 9 and IPFIX.
- sFlow version 5
- jFlow
Splunk Stream supports flow data sent over the UDP protocol.
Best practices for scaling flow ingestion
When scaling flow protocol ingestion, consider these best practices:
- Use Independent Stream forwarder for best results. See Deploy Independent Stream forwarder.
- Configure Nginx or another load balancer to distribute load among indexer cluster nodes.
- Disable SSL on the HEC input, if appropriate. (Do not disable SSL if you are sending data to Splunk Cloud, or if other security considerations apply.)
Note: Both Splunk Stream Forwarder and Splunk Independent Stream Forwarder deployments support flow protocol collection. However, due to the limited ingestion capabilities of the Splunk for Stream Wire Data used by Splunk_TA_stream
, we recommended using Splunk Stream Forwarder for low bandwidth or aggregated NetFlow capture only.
Configure flow data ingestion
To ingest flow data, configure streamfwd
to receive data at a specific IP address and port and specify the flow protocol. To do this, add a set of flow configuration parameters to streamfwd.conf
as follows:
- Edit
local/streamfwd.conf
. - Add the following parameters to specify the the IP address to bind to, the port number to bind to, and the flow protocol.
netflowReceiver.<N>.ip = <ip_address> netflowReceiver.<N>.port = <port_number> netflowReceiver.<N>.decoder = <flow_protocol>
For example, to receive NetFlow and sFlow data at IP address 172.23.245.122 on port 9995 and 6343 respectively, configure
streamfwd.conf
as shown:[streamfwd] logConfig = streamfwdlog.conf port = 8889 netflowReceiver.0.ip = 172.23.245.122 netflowReceiver.0.port = 9995 netflowReceiver.0.decoder = netflow netflowReceiver.1.ip = 172.23.245.122 netflowReceiver.1.port = 6343 netflowReceiver.1.decoder = sflow
For high volume with NetFlow data, configure additional NetFlow processing threads as shown:
netflowReceiver.0.decodingThreads = 4
- Restart Splunk.
By default, the netflowReceiver.<N>.ip
parameter binds to the first available IP address. There are no default values for netflowReceiver.<N>.port
and netflowReceiver.<N>.decoder
configuration parameters.
Configure proprietary element mapping
Splunk Stream supports mapping of IPFIX proprietary elements to Stream forwarder vocabulary terms. This lets you add and specify proprietary flow elements as fields in NetFlow protocol stream configurations that you create in the Configure Streams UI. To implement this feature, contact your Splunk support representative.
Flow data search syntax
To run searches for NetFlow or sFlow protocol data use the following search syntax:
sourcetype=stream:netflow sourcetype=stream:sflow
Create flow protocol streams
Once you configure streamfwd.conf
for flow data ingestion, you can use the Configure Streams UI in the Splunk App for Stream to create NetFlow and sFlow protocol streams with unique field definitions. See Configure Streams.
How NetFlow event timestamps are calculated
If you have any of the following fields in a your NetFlow data, Stream Forwarder sets the Splunk timestamp
field to be the value contained in the NetFlow flowStart*
field and the Splunk endtime
field value to be the value contained in the NetFlow flowEnd*
field.
flowStartSeconds
flowEndSeconds
flowStartMilliseconds
flowEndMilliseconds
flowStartMicroseconds
flowEndMicroseconds
flowStartNanoseconds
flowEndNanoseconds
For NetFlow records that are not flow related, when observationTime*
fields are available, Stream Forwarder populates the Splunk timestamp
and endtime
fields values from the NetFlow observationTime*
.
If you have both flowStart*
and observationTime*
fields in your NetFlow data, Stream Forwarder sets the Splunk Search timestamp
to be the NetFlow flowStart*
value and the Splunk Search endtime
field to contain the NetFlow observationTime*
value.
If none of the above fields are present, and a NetFlow record has the following fields:
- "first switch"(flowStartSysUpTime)
- "last switch"(flowEndSysUpTime)
- "system uptime"
- "current device time in unix epoch"
then Stream Forwarder calculates the Splunk Search timestamp
and endtime
as follows:
timestamp
= ("device time in unix epoch" - "system uptime") + "first switched"(flowStartSysUpTime)endtime
= ("device time in unix epoch" - "system uptime") + "last switched"(flowEndSysUpTime)
Ingest PCAP files | Use Stream configuration templates |
This documentation applies to the following versions of Splunk Stream™: 7.3.0, 7.4.0, 8.0.0
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