Elastiflow is a high performance flow collector that provides unparalleled network observability. The community edition is free so it’s perfect for homelabbers.

Why use Elastiflow?

Note: This guide is not recommended for production use. It is a POC for home lab use.

Setting up Elastiflow

Visit this link to obtain a Basic Free License.

Follow these steps to install Elastiflow.

Don’t follow the steps under Running the Collector to start Elastiflow yet.

Setting up Elastic

Follow these steps to set up an Elastic stack. I was able to get away with 8GB RAM and 2 vCPUs for a small 100 mbps connection.

In addition to the steps above:

  • update /etc/kibana/kibana.yml with the correct IP addresses and certificate locations.
  • update /etc/elasticsearch/elasticsearch.yml with the correct IP addresses and certificate locations.
  • update /etc/elasticsearch/jvm.options.d/heap.options to an appropriate JVM heap size. 12GB was too high - I reduced this to 512MB for home lab purposes.
  • update /etc/systemd/system/flowcoll.service.d/flowcoll.conf
    • Uncomment Environment="EF_FLOW_ACCOUNT_ID=, Environment="EF_FLOW_LICENSE_KEY=, Environment="EF_FLOW_LICENSED_UNITS=1 and add the license details (you should receive this via email).
    • Uncomment and set the following values:Environment="EF_FLOW_OUTPUT_ELASTICSEARCH_ENABLE=true" and Environment="EF_FLOW_OUTPUT_ELASTICSEARCH_ECS_ENABLE=true"
    • Set Environment="EF_FLOW_OUTPUT_ELASTICSEARCH_TLS_CA_CERT_FILEPATH=/etc/elastiflow/ca/ca.crt"

Setting up NetFlow on Unifi USG

Unifi USG Router uses VyOS. We will use this as a reference.

NetFlow config consists of two steps:

  1. Configure interfaces to collect NetFlow data on.
  2. Configure flow-accounting settings which apply to all interfaces.

SSH into the USG. Use configure to put the USG into edit mode.

For step one, with ip -a check the interfaces which you want to monitor. Use set system flow-accounting interface <interface e.g. eth1>.

For step two:

  • set system flow-accounting netflow enable-egress
  • set system flow-accounting netflow enable-ingress
  • set system flow-accounting netflow engine-id 1
  • set system flow-accounting netflow server <server IP> port 9995
  • set system flow-accounting netflow version 9
  • set system flow-accounting netflow sampling-rate 10
  • set system flow-accounting syslog-facility daemon
  • commit

To reverse any commands, substitute set with delete.

To show existing configuration, substitute set with show

To check if NetFlow is being exported, run sudo tcpdump -i any -n port 9995 on the USG or the Elastiflow box.

Some references:

Future Setup

  • Persistent USG configuration.
  • Enabling Elastiflow enrichment features.
  • Multi-cluster Elastiflow with Kubernetes/Docker.
  • Ansible automation.