# Performing network measurements

This section of the magma guide provides guidance for how to perform and orchestrate network measurements. It currently contains only OONI-developed software as we are reviewing more software that can be added to this section. Please feel free to propose other software or contribute by adding a section to the guide on how to perform network measurements with other software.


OONI, the Online Observatory of Network Interference, develops software with which users can perform network measurement to detect Internet censorship or other forms of network interference. The measurement tool that performs the measurements is called OONI Probe. By using the OONI Probe client, users can collect data to use as evidence of Internet censorship because the data returned will show how, when, where, and who implemented any network interference.

OONI probe runs on various OS types (Android, iOS, macOS, and Linux) and user interfaces (command-line, Web, and native graphical). The various clients (versions) have been developed in different programming languages with the Twisted networking framework is being used for desktop, servers, and embedded devices; mobile platforms use the portable C++11 network measurement library measurement-kit.

Official supported software for OONI Probe, along with installation instructions, can be found here: OONI Probe.

# Available tests

A high-level description of the different types of OONI software tests that you can run to detect interference can be found here: OONI Nettest.

A more detailed list of the test specifications, as well as experimental tests, can be found here: OONI Spec Nettests.

The various OONI Probe versions have different functionalities and testing capabilities. The table below lists the different test versions and shows their availability by software platform:

Test name Android iOS macOS macOS (legacy) Linux Linux (legacy) Windows
Bridge Reachability ✔️ ✔️
Captive Portal ✔️ ✔️
DASH ✔️ ✔️ ✔️ ✔️ ✔️
DNS Consistency ✔️ ✔️
DNS Injection ✔️ ✔️
DNS Spoof (deprecated) ✔️ ✔️
Facebook Messenger ✔️ ✔️ ✔️ ✔️ ✔️ ✔️ ✔️
HTTP Header Field Manipulation ✔️ ✔️ ✔️ ✔️ ✔️ ✔️ ✔️
HTTP Host ✔️ ✔️
HTTP Invalid Request Line ✔️ ✔️ ✔️ ✔️ ✔️ ✔️ ✔️
HTTP Requests ✔️ ✔️
Lantern ✔️ ✔️
Meek Fronted Requests ✔️ ✔️
Multi Protocol Traceroute ✔️ ✔️
NDT ✔️ ✔️ ✔️ ✔️ ✔️ ✔️ ✔️
OpenVPN ✔️ ✔️
Psiphon ✔️ ✔️ ✔️ ✔️ ✔️
TCP Connect ✔️ ✔️
Telegram ✔️ ✔️ ✔️ ✔️ ✔️ ✔️ ✔️
Vanilla Tor ✔️ ✔️
Web Connectivity ✔️ ✔️ ✔️ ✔️ ✔️ ✔️ ✔️
WhatsApp ✔️ ✔️ ✔️ ✔️ ✔️ ✔️ ✔️
bridgeT (deprecated) ✔️ ✔️

# Fingerprintability

OONI Probe is a network measurement tool that performs various tests to detect potential interference on a network. Like any other software or remote computing device that transmits network packets, OONI Probe software can therefore be distinguished on a network by having a unique (or quite unique) fingerprint.

A digital “fingerprint” is any information about a device or software that transmits network packets that can be collected for the purpose of identification or classification of the device. A fingerprint may reveal certain characteristics of the underlying client or other related information that can be used to identify a specific device/system/software. Smart TVs, for example, have a very unique fingerprint and can be easily distinguished in a network.

The OONI team has undertaken significant effort to reduce the fingerprintability of OONI Probe. Nonetheless, there are still certain common identifiers and characteristics related to the OONI Probe that should be considered when users are deciding whether to perform network measurements with OONI Probe.

# User agent identification

A user agent (UA or user-agent) string consists of one or more product identifiers, each followed by zero or more comments which together identify the user agent software and its significant subproducts (source: RFC 7231). An example of a user agent string is the name and version of the operating system, device, and software used for the network packets transmission.

The following table lists user agent strings transmitted by various OONI Probe tests.

Test Name User-Agent
Captive Portal Test Apple, Microsoft and Mozilla vendor specific (details)
HTTP Requests Test "User-Agent": "Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.2) Gecko/20100115 Firefox/3.6"
Header Field Manipulation Test Randomly selected variants of Mozilla Firefox and Safari web browsers
Web Connectivity Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.106 Safari/537.36

As mentioned, OONI carefully chooses the user agent strings used by various tests with the goal of minimizing fingerprintability risk for users running OONI Probe.

# Further resources

The sources below provide additional information regarding the anonymity tests of web browsers and fingerprintability of user agents.

# Helpers

This section lists available tools that can be used by users to help streamline the process of running tests (network measurements) with OONI Probe.

# OONI Run

The OONI run website allows users to share their custom OONI tests with a list of URLs. The website generates a special type of link that instructs OONI Probe to run specific tests (as defined by the OONI Run). Complete instructions and an introductory post on OONI run can be found here: https://ooni.org/post/ooni-run/.

Please note if you have a long list of URLs to enter, you can simply copy and paste them into the first URL slot on the OONI Run website. Your list of URLs should be formatted as either one URL per line:


Or with a space separating each entry:

https://www.example1.net https://www.example2.org

Source: OONI Run website

# OONI Run (offline version)

The OONI Run link generator script (rungen.py) generates an OONI Run link without the need to access an online website. It also allows users to programmatically generate OONI Run links. This is the Python version of the original ooni-run script (it uses Python version 3). Usage and instructions on how to run the script can be found here: OONI-rungen usage.

Source: ooni-rungen

# Hardware-assisted network measurements

# Lepidopter

Lepidopter is a Raspberry Pi distribution image with all the required dependencies and software packages in place, configured to run network measurement tests via the OONI Probe software. It is developed and designed to require no physical attendance upon first start (boot up of the device), but also allows experienced users to further configure it as they wish. The source code and the building scripts of the Lepidopter image are free and open source software (the image is based on the python (legacy) version of OONI Probe). Lepidopter currently requires the minimal physical attendance possible to perform longitudinal, daily network measurements with OONI Probe.

You can read the complete installation instructions here: Lepidopter Installation: Help Guides and Resources. Or you can simply download and copy the image to an SD card here: Lepidopter releases.

# Risks

As with any type of network measurement research, using OONI Probe involves risks. Fortunately, the OONI team has taken many precautions to minimize risks associated with their software and has published extensive documentation and guidelines on the potential risks associated with the possession, installation, usage, and submission of network measurements from OONI Probe. You can read about them here: Risks: Things you should know before using OONI Probe.

The potential risks associated with running network measurements via OONI Probe can be summarized as (taken verbatim from the following source):

  • Anyone monitoring your internet activity (e.g. ISP, government, employer) will be able to see that you are running OONI Probe;

  • OONI’s Web Connectivity test connects to and downloads data from a broad range of sites, including provocative or objectionable sites (e.g. pornography), which might be illegal in some countries;

  • By default, all network measurement data collected by OONI Probe is published to increase transparency of internet censorship, foster public debate, and support research. However, sending local network information to foreign servers might not be viewed favourably by some governments. While the data published is restricted to what is necessary to identify cases of censorship (and we do our best to not publish IP addresses), motivated ISPs might attempt to identify OONI Probe users through public OONI data.

Additionally, OONI has compiled a threat model document that outlines hypothetical security risks for OONI's associated roles; a distinct set of behaviors and interests with respect to OONI's operation.

Provided below are the relevant potential privacy risks and threats associated with using OONI Probe. These sections on Bad Report Data, Bad Non-Report Data, Deanonymizing Data Correlation, and Resource Risks are drawn verbatim, with omissions of non-relevant portions, from OONI's threads document. The complete version of this section can be found in OONI - Threats.

# Bad Report Data


These threats involve the production or consumption of report data itself. An attacker may attempt to modify or influence report data, or they may use report data to compromise privacy.


"Toxic" Report Data - Whose contents is a risk for someone, even when accurate.

  • Privacy-compromising (actual and perceived):

    • OONI Probe operator: Usage exposure - Reports exposing that a OONI Probe Operator uses OONI Probe
    • OONI Probe operator: Personal exposure - Reports exposing personal information of the OONI Probe Operator
  • Illegal data - Illegal data distinct from privacy exposing data -- e.g. child abuse material

# Bad Non-Report Data


"Toxic" Non-Report Data - This potential data gathered "out of band" represents a risk to various roles.


This is distinct from Bad Report Data. In the case of Bad Report Data, an attacker manipulates the storage/publication of the data, or they use the publicly available report data to subvert privacy assumptions. In this section, an attacker relies on non-report data such as web server logs, proxy logs, etc...

  • Privacy-compromising (actual and perceived):
    • OONI Probe operator: Usage exposure from traffic - Network traffic exposing that a OONI Probe operator uses OONI Probe -- e.g. An HTTP net-test has an identifiable signature gathered from the target web server. e.g. An SSL net-test has an identifiable signature gathered from passive traffic recording of a handshake.
    • OONI Probe operator: Usage exposure from local forensics - A forensic examination of a OONI Probe operator's host reveals the use and history of OONI Probe operation.
    • OONI Probe operator: Personal exposure from traffic - Network traffic exposing personal information of the OONI Probe Operator -- e.g. net-test traffic includes filesystem paths, revealing the user name.
    • Bystander personal: Exposure from traffic - Network traffic exposes personal information of arbitrary Bystanders, for example, due to net-test inputs supplied to a test deck. e.g. A OONI Probe Operator provides the URL for a specific Facebook user to OONI Probe, and a search over passive network logs matches that particular Facebook account.
    • Private infrastructure: Exposure from traffic - Network traffic exposing private infrastructure details -- e.g. an HTTP net-test passes through a bystander's transparent proxy which adds a header with its IP address.

# Deanonymizing Data Correlation


This category represents a risk to privacy due to correlation from multiple data sources, including report and non-report data.

  • OONI Probe operator: usage exposure from correlation - The fact that a OONI Probe operator ran OONI Probe can be deduced by correlating multiple data source -- e.g. Timing information in published reports and router logs are analyzed together to determine a OONI Probe operator was running OONI Probe.

  • OONI Probe operator: personal exposure from correlation - Personal details about a OONI Probe operator can be deduced by correlating multiple data source -- e.g. Timing information in published reports, router logs, and video recordings from an internet cafe are analyzed together to determine the face or identity of a OONI Probe operator.

  • Bystander: personal exposure from correlation - Multiple data sources are correlated to deduce personal information about a Bystander -- e.g. Timing information from published reports along with censoring firewall policy change time correlation reduce the IP search space to a small set and all users of an ISP are investigated.

  • Private infrastructure: exposure from correlation - Data correlation reveals details about private infrastructure -- e.g. A report includes reverse DNS lookups with associated timing information, which is correlated to DNS server logs to deduce details about the OONI Probe operator's DNS configuration.

# Resource Risks



This section is about abusing resources (whether intentional or inadvertant) independent of report data or non-report data privacy issues. Threats involving report or non-report data often also involve resource abuse, so these are distinct, but non-overlapping categories of threat.

Direct Compromise

  • OONI Probe compromise via net-test - A vulnerability in a net-test allows the network or measurement target hosts to compromise the OONI Probe host.
  • OONI Probe compromise via collector - A vulnerability in the collector lookup mechanism, or collector client allows a malicious lookup service (such as mlab-ns) or collector to compromise the OONI Probe host.

Leveraged Attacks

These threats involve abusing OONI infrastructure to attack other systems.

  • OONI Probe localhost leveraged attack - A vulnerability in OONI Probe allows a remote attacker to attack other processes on the OONI Probe host. e.g. A user is running a service which accepts connections only from localhost, and a malicious test input causes OONI Probe to reflect an attack vector to that internal third-party service.
  • OONI Probe extra-host leveraged attack - A vulnerability in OONI Probe allows a remote attacker to attack other hosts via the OONI Probe process. e.g. A malicious input causes OONI Probe to forward a remote expoit to a vulnerable third party web server.

# Data policy

OONI Probe allows users to opt-out from having their data (network measurements) published in OONI's database. You can review the complete list of opt-out options here: OONI Data Policy.

The data collected by OONI is summarized in the following table.

Type of data collected Opt-out option
Country code ✔️
Data format version
Date and time of measurements
IP address (not collected by default) ✔️ (default)
Network city (probe_city) ✔️
Network info (ASN) ✔️
Network measurements ✔️
Network type (mobile/wifi)
OONI Probe's DNS resolver IP
OONI Probe's engine name and version
OONI Probe's platform, and version
OONI backend version
Report filename
Test helpers used
Test input (URL, IP)
Test name, options used, run and start time

OONI Data formats specification describes all data options used by the OONI software.