ET Pro Telemetry edition

Todays cybersecurity engineers need timely and accurate data about eminent threats and how they spread around the globe. With this data cybersecurity researchers and analysts can improve the detection of malicious network traffic. The times when we could rely on just firewall rules for our protection are long gone. Additional layers of security are desperately needed to guard against these attacks.

With growing risks the need to fortify our security is growing for both big enterprises as for SMEs alike, but often out of reach for the latter. An important extra security addition is an Intrusion Detection and Prevention System (IDS/IPS).

The IDS/IPS available in OPNsense is based on Suricata. This open source IDS/IPS engine has proven its value in OPNsense, especially in combination with the free Proofpoint ETOpen ruleset.

The need for valuable threat detection data and the increasing importance of additional network security has brought Proofpoint and OPNsense together. Our joined efforts resulted in the ET Pro Telemetry edition.

The ET Pro Telemetry edition embraces our vision that sharing knowledge leads to better products.

When you allow your OPNsense system to share anonymized information about detected threats - the alerts - you are able to use the ET Pro ruleset free of charge.

The ET Pro ruleset is updated daily and covers more than 40 different categories of network behaviors, malware command and control, DoS attacks, botnets, informational events, exploits, vulnerabilities, SCADA network protocols, exploit kit activity, and more. If offers a great improvement over the ET open ruleset.


When you register for this (free) service, you will share your basic (company) details with us, Deciso Sales B.V.. We will register your sensor(s) anonymized at Proofpoint.


When ET Pro Telemetry is activated, your OPNsense system sends data to Proofpoint. Proofpoint does not know who you are, they only know how many sensors an account owns. Your network statistics received by Proofpoint won’t be shared with us.

Sign up for ET Pro Telemetry edition here


After registration, we can proceed to the installation steps, which are described below.


To use ET Pro Telemetry, you will need to have OPNsense 19.1 or higher installed. When using an older version, please upgrade to the latest first.


First we need to install the required plugin, which is responsible for collecting the telemetry data and provides access to the ET Pro ruleset.

  1. Go to System ‣ Firmware ‣ Updates
  2. press “Check for updates” in the upper right corner.
  3. open the tab “Plugins” and search for os-etpro-telemetry
  4. when found, click on the [+] sign on the right to install the plugin

A screen containing the installation status should appear now and the plugin is ready for use.

register token

Next step is to register your token in OPNsense and enable rulesets.

  1. Go to Services ‣ Intrusion Detection ‣ Administration
  2. Click on the “Download” tab, which should show you a list of available rules.
  3. Enable all categories you would like to monitor in the “ET telemetry” section, if in doubt enable all and monitor the alerts later (select on the right and use the enable selected button on top)
  4. At the bottom of the page there’s a block containing settings, paste the token code you received via email in et_telemetry.token
  5. Press save to persist your token code
  6. Press Download & Update rules to fetch the current ruleset

Schedule updates

To download the rulesets automatically on a daily bases, you can add a schedule for this task.

  1. Go to Services ‣ Intrusion Detection ‣ Administration
  2. Click on the “Schedule” tab
  3. A popup for the update task appears, enable it using the checkbox on top, and click “save changes”

Subscription status

To validate your subscription, we recommend to add the widget to the dashboard.

  1. Go to the dashboard Lobby ‣ Dashboard
  2. Click on “Add widget” in the top right corner, click “Telemetry status” in the list
  3. Close dialog and click “Save settings” on the right top of the dashboard
  4. Open Lobby ‣ Dashboard again to refresh the content

When everything is setup properly and the plugin can reach Proofpoint, it will show something like:


The status determines which ruleset your sensor will receive, ACTIVE or DORMANT your sensor will receive ET Pro rule, when DISABLED the license conditions are not met and ET Open will be served.

All timestamps underneath the status provide you with information when data was send or received from Proofpoint.


If your sensor will start sending events and heartbeats, it should switch to active after a certain amount of time.

In case your sensor can’t communicate to the outside world, the widget shows an error.



The system log (System ‣ Log Files ‣ General) might contain more information, search for emergingthreats

Information sent to Proofpoint ©

When the intrusion detection system logs events, they will be (partially) sent to Proofpoint in return for using the ET Pro Telemetry edition.

This paragraph describes the attributes from the eve.json log file that are collected to improve threat detection.

An example of an event is detailed below.

  "event_type": "alert",
  "proto": "IPV6-ICMP",
  "timestamp": "2018-04-17T18:38:04.498109+0200",
  "in_iface": "em1",
  "alert": {
    "category": "Generic Protocol Command Decode",
    "severity": 3,
    "rev": 2,
    "gid": 1,
    "signature": "SURICATA zero length padN option",
    "action": "allowed",
    "signature_id": 2200094
  "src_ip": "xxxx:xxxx:fec0:d65f",
  "flow_id": 982154378249516,
  "dest_ip": "ff01:fe00:1200:8900:0000:f000:0000:0016"

Network addresses are needed to identify hosts which pose a higher risk to your and other peoples network, but your internal addresses are kept secret.

For this reason we mask the addresses found in the log file and only send the last number(s) to identify the host. In the example above the src_ip is an internal IPv6 address, for IPv4 we only collect the last number (e.g. 0-255).

Fields collected (unmodified):

timestamp Timestamp of the event
flow_id Internal identifier for this communication flow
in_iface Interface where the event was captured
event_type Type of event
vlan Vlan tag
src_port Source port number
dest_port Destination port number
proto Protocol
alert Alert details, such as the signature_id, action taken and associated message.
tls TLS details, such as certificate subject and serial.
http HTTP detail information such as the host, but omitting sensitive details such as path and user-agent.
app_proto Application protocol (if known)

Threats change often, to keep statistics valuable, the list of fields is subject to change


The plugin comes with a small script to print eve output yourself, it’s called, when used with the -p parameter, it will output the data as it will be sent to Proofpoint. All script code can be found in the following directory /usr/local/opnsense/scripts/ids_telemetry/