Frequently Asked Questions (FAQ)

This Frequently Asked Questions (FAQ) section aims to address the questions that we are frequently asked by the community.

Are there other questions you would like us to address? Please let us know.

View a version of the OONI FAQ in Khmer by DigitalHub101.

About OONI

What is OONI?

The Open Observatory of Network Interference (OONI) is a free software project that aims to empower decentralized efforts in increasing transparency of internet censorship around the world.

Since 2012, OONI has released several censorship measurement apps (OONI Probe) and openly published millions of network measurements on internet censorship worldwide.

Why OONI?

You can use our free software tools, open methodologies, and open data to verify our findings, reproduce our studies, and investigate internet censorship in your country.

We created OONI to support public debate, and evidence-based reporting and advocacy on information controls.

What does OONI do?

To empower decentralized efforts in increasing transparency of internet censorship worldwide, we:

Why measure internet censorship?

Internet censorship can constitute a violation of human rights (such as the right to freedom of expression and the right to access information).

However, identifying the intentional blocking of sites and services can be tricky. Below are some reasons why:

  1. It’s harder to notice the blocking of less popular sites and services. Internet censorship is easier to notice when it affects services that we commonly use, or when their blocking receives media coverage. The blocking of Telegram and Instagram in Iran, for example, received a fair amount of media coverage and international attention, whereas the blocking of religious and ethnic minority sites may be less known.

  2. Internet censorship often differs across networks within a country. In many countries, Internet Service Providers (ISPs) block access to different websites, often as a result of vague government orders. A site may be accessible from one network and may be blocked in another.

  3. Most censorship techniques can be quite subtle. When an ISP serves a block page, they often inform you that a site is intentionally censored and they often include a legal justification. Some ISPs, however, serve blank block pages which can potentially create ambiguity on whether a site is intentionally blocked or inaccessible due to other reasons (such as a technical problem). In many countries, ISPs don’t serve block pages at all. Rather, they block sites by entirely different means (such as DNS tampering, TCP/IP blocking, or RST injection) which don’t inform users, nor provide a justification for the censorship. In these cases, it’s harder to determine whether a site is intentionally blocked, or if it’s inaccessible due to other reasons (such as a transient network failure or a case of DNS misconfiguration).

  4. Some ISPs adopt a combination of different censorship techniques. While your ISP may serve a block page for some sites (informing you that those sites are intentionally blocked), they may block different sites with different techniques – limiting your ability to notice the blocking of those other sites. In some countries, ISPs even block the same sites with different techniques.

  5. Over-blocking and collateral damage. In Indonesia, for example, Vimeo and Reddit were found to be blocked even though their ban was lifted more than 2 years ago. In Egypt, a number of sites that were hosted on the same CDN as The New Arab were blocked as well.

  6. The fact that a site or service is inaccessible doesn’t necessarily mean that it’s blocked by your ISP. Maybe it’s hosted on an unreliable server, or maybe the site/service owner is blocking all IP addresses originating from the country that you are trying to access it from (in compliance with laws and regulations).

Measuring internet censorship is, therefore, important because it allows us to inspect a network and to examine the reasons as to why and how we are (or aren’t) able to connect to an internet service.

When inspecting a network we observe, for example, that our ISP is spoofing the IP address of the website that we’re trying to access, this information can potentially serve as evidence of intentional interference with our ability to access the intended website.

Through the use of OONI Probe, you can measure networks and collect data that shows what is blocked, how, when, and by whom.

How is OONI funded?

Like most projects in the non-profit world, OONI is primarily supported through grants.

We are currently supported by the Bureau of Democracy, Human Rights, and Labor (DRL), the Ford Foundation, and the Internet Society (ISOC).

Over the years, the Open Technology Fund (OTF) has been our main funder, originally supporting the creation of OONI back in 2012. The OTF has supported some of the most prominent free software projects that advance human rights on the internet, such as Tor and Signal.

We have received support from Mozilla (Mozilla Open Source Support) to revamp OONI Explorer. The initial creation of OONI Explorer (originally launched in March 2016) was supported by the German Foreign Ministry. Over the years, we have received support from several other foundations as well, such as the Media Democracy Fund (MDF) and the National Science Foundation (NSF).

We have also received other forms of support, such as donations from companies like AirVPN and VPNCompare. We have received infrastructure support from Greenhost (who have been providing us servers since 2016) and Amazon (for hosting OONI measurements on Amazon S3 and for using their big data tooling for analyzing measurements).

What is OONI’s relationship with The Tor Project?

OONI was born out of The Tor Project.

Back in 2011, Tor Project developers started creating open methodologies and frameworks with the goal of measuring various forms of network interference, resulting in the creation of OONI. Over the years, OONI was one of the projects hosted under The Tor Project Inc..

The Tor Project served as OONI’s fiscal sponsor between 2012 to 2020, and we continue to collaborate on measuring Tor reachability.

OONI is currently fiscally sponsored by the Hermes Center for Transparency and Digital Human Rights, but we operate independently in terms of fundraising and governance.

Where is OONI based?

OONI is a global project, with a global community.

The OONI team is not from a specific country, as we’ve never had a physical office, and we’ve always worked online. Our current team members are from Italy, Greece, South Africa, and India.

OONI is a non-profit project, but doesn’t have a legally registered entity.

The Tor Project served as our fiscal sponsor between 2012 to 2020. More recently, we are fiscally sponsored by the Hermes Center for Transparency and Digital Human Rights, which is a non-profit digital rights organization registered in Italy.

Despite being fiscally sponsored by others (primarily the Tor Project over the years), we have always operated independently in terms of fundraising and governance.

How can I get involved?

There are many ways you can get involved!

OONI Probe

What is OONI Probe?

OONI Probe is free and open source software designed to measure internet censorship and other forms of network interference.

My country doesn’t have censorship. Why run OONI Probe?

We think it’s important to measure networks for censorship in every country of the world (regardless of whether cases of internet censorship have been reported or not) because:

What do OONI Probe tests do?

OONI Probe consists of multiple free software tests designed to measure:

How do OONI Probe tests measure internet censorship?

To measure the blocking of a website, OONI Probe automatically performs certain checks towards that website from two networks:

The results from the two networks are automatically compared. If they are the same, the tested website is considered accessible. However, if the results differ, it’s possible that access to the tested website is blocked.

You can learn how each OONI Probe test works through the links provided below:

You can also view the test specifications here: https://github.com/ooni/spec/tree/master/nettests

I am not a techie. Can I run OONI Probe?

Absolutely! You can install the OONI Probe mobile app (for Android and iOS), which is the easiest way to run OONI Probe. You can run tests with the tap of a button!

You can also run the OONI Probe desktop app, which includes similar design, UX, and features as the OONI Probe mobile app.

How can I run OONI Probe?

You can run OONI Probe on the following platforms:

I ran OONI Probe. Should I send you the results?

No need to. OONI Probe is designed to automatically send us your results as soon as you run a test (unless if you have opted-out in the settings). Your results will automatically get processed and published.

How often should I run OONI Probe?

As often as possible. Internet censorship can emerge abruptly, while the blocking and unblocking of internet services may change over time.

Ideally you could enable automated testing on Android, Desktop and Linux probes.

How can I run OONI Probe automatically?

You can enable the “Automated testing” settings in the OONI Probe apps.

In these settings, you have the option to only have OONI Probe run automatically when you’re connected to WiFi and/or your device is charging.

The Linux OONI Probe CLI runs automatically when installed using the .deb package.

For how long should I run OONI Probe?

As long as possible. Internet censorship can emerge abruptly, while the blocking and unblocking of internet services may change over time.

Every time you run OONI Probe, you contribute measurements to a public archive on network interference (since your measurements get published).

To more effectively track internet censorship over time, you would ideally run OONI Probe for as long as possible (years).

I found blocked websites. How can I circumvent their blocking?

You can circumvent the blocking of websites or apps through the use of Tor Browser or a VPN (such as Psiphon).

OONI Probe found a middlebox on my network. Does that mean I am under surveillance?

No, not necessarily.

Many Internet Service Providers (ISPs) use middleboxes for a wide range of networking purposes (such as caching), many of which have nothing to do with surveillance or implementing internet censorship.

Can I measure internet censorship remotely in another country?

OONI Probe tests are designed with the goal of measuring internet censorship as a user would experience it within a country. OONI Probe is designed to measure the network it connects to, in the country that that network is located.

If you perform tests remotely (without physically being located in that specific country) – for example, through the use of a VPS – you will likely receive inaccurate results because the OONI Probe heuristics are not designed for that.

For remote testing, we would recommend other tools, such as Satellite, which scans the internet for open DNS resolvers and performs queries to them in an attempt to identify DNS based blocking.

What types of data does OONI Probe collect?

OONI Probe was built with the privacy and security of its users in mind, but it’s not a privacy tool. We therefore try to limit data collection to types of data that are necessary for measuring various forms of internet censorship.

By default, OONI Probe collects:

By default, OONI Probe does not collect your IP address. You can, however, opt-in to submit your IP address (via the settings in the OONI Probe apps) if you would like to enhance the accuracy of information.

We might unintentionally collect your IP address and other personally-identifiable information if this is included in the HTTP headers or other metadata of measurements. This data might be collected if the websites OONI Probe is testing employ tracking technologies or contain custom content. We take measures to remove IP addresses and other potentially personally-identifiable information from our database of collected measurements to reduce the risk to you.

Learn more about our data practices through the OONI Data Policy: https://ooni.org/about/data-policy/

How can I opt-out from sending OONI measurements?

Through the settings of the OONI Probe apps, you can disable the “Automatically Publish Results” setting to opt-out from sharing (and publishing) any measurements at all.

What are the risks of running OONI Probe?

To our knowledge, no one has ever gotten into trouble as a result of running OONI Probe. That said, running OONI Probe can potentially be risky.

Some things to take into account:

To learn more about potential risks associated with the use of OONI Probe, please refer to our documentation: https://ooni.org/about/risks/

How can I reduce the risks associated with running OONI Probe?

We aim to provide you with as much choice as possible, so that you can mitigate potential risks and customize your usage of OONI Probe depending on what you feel comfortable with.

You can:

Can I run OONI Probe over a VPN?

We advise against running OONI Probe over a VPN because you wouldn’t be measuring your network. You would, instead, be measuring the network provider by your VPN, which is probably uncensored.

To capture internet censorship (as experienced by a local internet user), turn-off your VPN (or any other circumvention software) prior to running OONI Probe tests.

No. We are a team of software developers, and therefore cannot provide any legal advice.

We do, however, share some questions that you can ask your lawyers relating to the use of OONI Probe: https://ooni.org/about/risks/#seeking-legal-advice

Testing websites

Which websites will I test for censorship with OONI Probe?

When you tap “Run” in the OONI Probe apps, you will test the websites included in the following two lists:

No matter which country you’re running OONI Probe from, you will always test websites from the global test list.

OONI Probe will automatically determine which country-specific list to pick for testing based on the country you’re running OONI Probe from. For example, if you run OONI Probe in Brazil, you will test websites from the global test list and from the Brazilian test list. If you travel to Germany and run OONI Probe, it will test the websites from the global and German test lists.

What are test lists?

A test list is a list of websites tested for censorship.

Why does OONI Probe use test lists?

Testing all of the websites hosted on the internet is not feasible, especially since OONI Probe is run by users with bandwidth constraints. We therefore need to limit the testing to a selection of websites.

Test lists offer the following main advantages:

Why doesn’t the OONI Probe mobile app test all of the websites in test lists?

Due to bandwidth constraints, default website testing via the OONI Probe mobile app is limited to 90 seconds. OONI Probe will select a random sample of websites (from the global and country-specific list) and connect to as many of them as it can within 90 seconds.

The OONI Probe desktop app tests all websites (from the global and country-specific list) in one go and you can limit the number of tested websites in the app settings.

How can I change the testing duration in the OONI Probe mobile app to test more websites?

To test more websites, change the testing duration via the following steps:

  1. Tap on the Websites card in your OONI Probe mobile app

  2. Tap on the menu icon on the top right corner (inside the Websites card)

  3. Tap on “Test duration”

  4. The default is 90 (seconds). Change this number to allow for longer testing.

  5. Tap “OK”

How can I find my country’s test list?

The test list of each country is saved as a CSV file in the Citizen Lab’s test list repository on GitHub.

These files have been saved in the following format: country code dot csv. For example, the Brazilian test list has been saved as br.csv (since “BR” is the country code for Brazil).

You can find your country’s test list by searching for a CSV file with its country code.

Why doesn’t my country have a test list?

If you can’t find a test list for your country, that’s probably because it doesn’t exist yet. In this case, OONI Probe would only test the websites included in the global test list.

Please help us create a test list for your country.

Who decides which websites are included in test lists?

Anyone can! Test lists are publicly hosted on GitHub by the Citizen Lab to encourage community review and contributions.

We encourage you to review which websites are included in test lists and to propose additional URLs.

How can I contribute to test lists?

Detailed information explaining how to contribute to test lists is available through our guide: https://ooni.org/get-involved/contribute-test-lists/

If you’re a GitHub user, you can contribute to test lists by opening a pull request.

I’m not a GitHub user, but I’d still like to submit URLs for testing. How can I do so?

Some of the greatest test list contributions come from people who don’t use GitHub (such as social scientists), particularly since updating test lists requires an understanding of the country’s social and political environment.

If you’re not a GitHub user and would like to contribute to test lists, please refer to our guide and send us your updates by dropping us an email at contact@openobservatory.org.

What is the difference between a test list and a blocklist?

A test list is a list of sites that we test to check whether they are blocked.

A blocklist, on the other hand, is a list of (legally) prohibited websites, all of which are often blocked.

Some governments occasionally publish official blocklists (or they get leaked) which contain lists of websites that are legally prohibited in a country. Internet Service Providers (ISPs) are then ordered to block access to all websites included in such blocklists, commonly involving hundreds (or thousands) of URLs that contain content illegal in that country (such as gambling, file sharing, adult content, etc.).

Test lists, on the other hand, are not meant to be limited to blocked websites. Rather, they serve the purpose of monitoring when policies change - what’s most likely to be blocked or unblocked.

While test lists may include some websites that are known to be blocked (and that is useful for detecting censorship techniques adopted by ISPs), most sites are not censored locally when they are added to test lists.

With test lists, we aim to discover internet censorship (by identifying the blocking of sites that were previously accessible), not only confirm it.

How can I test all the URLs included in an official blocklist?

Blocklists often include thousands of URLs and due to bandwidth constraints, we refrain from including all of those websites in test lists (though we do add a few). We generally try to limit test lists to around 1,000 URLs, and we try to ensure that the URLs are as diverse as possible.

You can test an entire blocklist through the following steps:

  1. Install the OONI Probe mobile app

  2. Save the URLs of the blocklist in a text file and ensure that:

    • Each URL is included in a separate line.

    • URLs are formatted properly (i.e. they include the HTTP or HTTPS prefix, depending on how they would appear when accessed from a normal browser): This is particularly important since URLs in blocklists are often not formatted properly and this would influence the testing.

  3. Access the OONI Run website

  4. Copy your (saved) list of blocklist URLs and paste it into the first URL slot in the OONI Run website.

The URL slots should now be populated with the blocklist URLs.

  1. Click on the “Generate” button (in the OONI Run page) at the end of all the URLs.

You have now generated a link (and widget code) for OONI Probe testing of the blocklist URLs.

  1. Open the generated link with your OONI Probe mobile app (not with a web browser!).

You should now view the blocklist URLs in your OONI Probe mobile app.

  1. Tap “Run” to test the blocklist URLs.

Once the testing has been completed, you will find the results in the Test Results section of your OONI Probe mobile app. The results will also automatically be published on OONI Explorer within 24 hours (unless if you disable publication in the app settings).

What types of websites will OONI Probe test?

OONI Probe tests websites (included in the Citizen Lab test lists) that fall under 30 diverse categories.

These categories range from news media, culture, and human rights issues to more provocative or objectionable categories, like pornography (the latter are included because they are more likely to be blocked, enabling the detection of censorship techniques adopted by ISPs).

How can I choose which types of websites to test?

By default, OONI Probe will test websites that fall under 30 standardized categories.

You can limit your testing to specific types of websites (for example, only test media websites) through the following steps:

How can I choose which websites to test?

You can test websites of your choice (rather than the websites included in test lists) through the following steps:

  1. Tap on the Websites card in your OONI Probe mobile app

  2. Tap on the “Choose websites” button (inside the Websites card)

  3. Add the websites you want to test in the URL slots (ensure each website is formatted properly)

  4. Tap “Run”

Once the testing has been completed, you will find the results in the Test Results section of your OONI Probe mobile app. The results will also automatically be published on OONI Explorer within 24 hours (unless if you disable publication in the app settings).

How can I test a custom list of URLs?

If you would like to test a long list of websites, adding them one by one via the “Choose websites” button in the OONI Probe mobile app might not be a pleasant option.

You can test your own custom list of URLs through the following steps:

  1. Install the OONI Probe mobile app

  2. Save the URLs of your list in a text file and ensure that:

    • Each URL is included in a separate line

    • URLs are formatted properly (i.e. they include the HTTP or HTTPS prefix, depending on how they would appear when accessed from a normal browser)

  3. Access the OONI Run website

  4. Copy your list of URLs and paste it into the first URL slot in the OONI Run website.

The URL slots should now be populated with your list of URLs.

  1. Click on the “Generate” button (in the OONI Run page) at the end of all the URLs.

You have now generated a link (and widget code) for OONI Probe testing of your URL list.

  1. Open the generated link with your OONI Probe mobile app (not with a web browser!).

You should now view your list of URLs in your OONI Probe mobile app.

  1. Tap “Run” to test the URLs.

Once the testing has been completed, you will find the results in the Test Results section of your OONI Probe mobile app. The results will also automatically be published on OONI Explorer within 24 hours (unless if you disable publication in the app settings).

OONI data

What is OONI data?

OONI data are network measurements collected through OONI Probe tests.

Why does OONI publish data?

Every day, we openly publish all measurements we collect from OONI Probe users around the world to:

Where does OONI publish data?

Every day, we publish measurements from around the world via the following two resources:

How can I interpret OONI data?

Each OONI measurement is generated from an OONI Probe test. Depending on how each OONI Probe test functions, each OONI measurement has a very specific data format. This therefore varies from test to test.

Generally, OONI Probe tests will present one of the following three types of results:

How can I fetch and analyze OONI data?

You have the following options:

We recommend fetching OONI data from the S3 bucket if you plan on working with large volumes of OONI data (including, for example, downloading all the measurements from a country to perform queries).

Given that other tools (such as OONI Explorer) depend on the OONI API, it’s best to limit the use of the API to light-weight queries (to avoid affecting the performance of the other tools that rely on it).

OONI Explorer

What is OONI Explorer?

OONI Explorer is an open data resource on internet censorship around the world. It hosts millions of OONI measurements collected from more than 200 countries since 2012. Every day, hundreds of thousands of new OONI measurements are openly published on OONI Explorer from around the world.

How can I find blocked websites via OONI Explorer?

You can view the most recently blocked websites around the world via the following steps:

  1. Access OONI Explorer

  2. Click on “Search” (top right corner)

  3. Select “Confirmed” (under “Status” in the filter options on the left)

  4. Click “Filter Results”

All of the OONI Explorer measurements will now be filtered to only show you those where websites have been confirmed blocked around the world (based on OONI Probe testing).

To view websites that are possibly blocked:

  1. Click on “Search” (top right corner of OONI Explorer)

  2. Select “Anomalies” (under “Status” in the filter options on the left)

  3. Click “Filter Results”

However, interpret these results with caution, as they may contain false positives.

How can I access measurements?

You can find OONI measurements (i.e. OONI Probe test results) through the following steps:

  1. Access OONI Explorer

  2. Click on “Search” (top right corner)

Every row you will now see (in the Search page) – containing country codes, ASNs, dates, and test names – is each an individual measurement (OONI Probe test result).

For example:

OONI measurement

  1. Click on each measurement to access it.

An example of a measurement page:

OONI measurement page

How can I find OONI data via OONI Explorer?

If you scroll down in any OONI measurement page (example measurement page), you will view the raw network measurement data – which you can also download in JSON format.

The network measurement data will differ depending on the OONI Probe test from which it was generated.

How can I find “evidence of internet censorship” in a measurement?

First, there are two things to consider:

Based on this, you can easily find evidence of internet censorship through the following steps:

  1. Click on “Search” (top right corner of OONI Explorer)

  2. Select “Confirmed” (under “Status” in the filter options on the left)

  3. Click “Filter Results”

All OONI measurements will now be filtered to only show you those where ISPs around the world served block pages for websites. The results will be listed from the most recent cases, and they will automatically be updated with new measurements every day.

  1. Click on a measurement

Example of a “confirmed blocked” measurement:

Confirmed blocked measurement

  1. Scroll down to view the raw network measurement data

Raw measurement data

You can download the data in JSON format.

Similarly to the steps shared above, you can also find cases of internet censorship by selecting “Anomalies” (instead of “Confirmed”) under the “Status” section of the OONI Explorer search tool. However, confirming those cases is more tricky and it’s probably best to consult with an engineer.

How can I find blocked websites in my country?

You can find the websites that are blocked in your country through the following steps:

  1. Access OONI Explorer

  2. Click on “Search” (top right corner)

  3. Select your country via the “Country” drop-down menu on the left

  4. Select “Web Connectivity” via the “Test Name” drop-down menu on the left

  5. Select “Anomalies” and/or “Confirmed” (under “Status”)

  6. Click “Filter Results”

Please interpret the “anomalous” results with caution, as they may contain false positives.

“Confirmed” blocked results will only appear if the tested ISPs served block pages for those specific websites.

How can I check if a specific website is blocked?

You can check whether a specific website (such as twitter.com) is blocked through the following steps:

  1. Access OONI Explorer

  2. Click on “Search” (top right corner)

  3. Select a country via the “Country” drop-down menu on the left

  4. Select “Web Connectivity” via the “Test Name” drop-down menu on the left

  5. Type the domain (e.g. twitter.com) of the website in the “Domain” slot

  6. Select “Anomalies” and/or “Confirmed” (under “Status”)

  7. Click “Filter Results”

Please interpret the “anomalous” results with caution, as they may contain false positives.

“Confirmed” blocked results will only appear if the tested ISPs served block pages for those specific websites.

Why can’t I find results for a specific website?

If you search for the results pertaining to a specific website (based on the instructions shared in the previous answer) and you don’t find any results, that’s likely due to one of the following reasons:

How can I check the blocking of websites during a specific time period?

To narrow down the results to a specific time frame, use OONI Explorer in the following way:

  1. Click on “Search” (top right corner)

  2. Select a country via the “Country” drop-down menu on the left

  3. Select “Web Connectivity” via the “Test Name” drop-down menu on the left

  4. Specify the time period by selecting dates through the “From” and “Until” calendars

  5. Select “Anomalies” and/or “Confirmed” (under “Status”)

  6. Click “Filter Results”

Please interpret the “anomalous” results with caution, as they may contain false positives.

“Confirmed” blocked results will only appear if the tested ISPs served block pages for those specific websites.

What do you mean by “Confirmed”?

A measurement is “confirmed blocked” when we are absolutely sure that the tested resource is blocked. Based on our current heuristics, this can only apply to websites when an Internet Service Provider (ISP) serves a block page (which notifies the user that the website is intentionally blocked).

By selecting “Confirmed” via OONI Explorer, you will view all the OONI Probe testing results where we confirmed the blocking of websites around the world.

I know of many other websites that are blocked. Why doesn’t OONI Explorer show them when I select “confirmed”?

The “Confirmed” option will only render results (blocked websites) for cases when all of the following apply:

As we are always working on improving our censorship detection heuristics on an ongoing basis, these cases will likely change over time. For more technical insight, check out the code for the ooni/pipeline.

Why does OONI confirm censorship when a block page is served?

A block page is a web page that informs the user that the intended website is intentionally blocked. Often, a block page even cites the relevant legal justification for the blocking. There is, therefore, no ambiguity around this form of censorship, as even the ISP is transparent about the intentional blocking involved.

Example of a block page served by ISPs in Indonesia:

Indonesian block page

Furthermore, block pages contain fingerprints which enable their automated detection. Once we have detected a block page fingerprint and added it to our database, we can scan measurements in search of all other measurements that contain the same fingerprint. As a result, we can automatically detect the blocking of many other websites.

Why doesn’t OONI confirm other cases of internet censorship (beyond block pages)?

Other censorship cases (such as DNS tampering or TCP/IP blocking) are more subtle, since the ISP doesn’t explicitly inform the user that they are intentionally blocking access to a specific website (as they do in the case of a block page).

Furthermore, there are many reasons why those cases might look like censorship, but actually not be (which makes their automatic detection trickier). For example, tests run on an unstable network may generate TCP/IP errors, which may have nothing to do with intentional TCP/IP blocking. It may also be the case that a tested website is hosted on an unreliable server, or that the website owner is blocking access to IP addresses that originate from that specific country. Or perhaps DNS anomalies show up as a result of DNS misconfiguration, rather than due to intentional DNS-based blocking.

It’s therefore often necessary to examine each measurement on a case-by-case basis in order to inspect the data carefully and determine the precise reason why its testing didn’t succeed.

Automatically distinguishing cases of intentional censorship from the countless other reasons why network anomalies can occur has been an ongoing challenge, though we continue to make improvements to our heuristics on an ongoing basis and plan to automatically confirm more forms of internet censorship soon.

What do you mean by “Anomalies”?

An “anomalous” measurement is a testing result which is flagged because it presents signs of potential network interference (such as the blocking of a website or app, or the presence of a middlebox).

When a block page is detected, OONI flags that measurement as “confirmed”. All other cases of internet censorship (such as DNS tampering or TCP/IP blocking) are included in “anomalous” measurements.

However, an anomalous measurement does not necessarily contain evidence of internet censorship, as it might be a false positive.

Essentially, an anomalous measurement signals that something is wrong and that we should look deeper into the measurement data to determine what is happening.

Why does OONI Explorer suggest that a site or app that I can access is blocked in my country?

There are two reasons why this may happen:

  1. Perhaps the website or app in question was blocked by other Internet Service Provider(s) in your country, and not by your ISP.

  2. The testing result is a false positive. The following two questions and answers address this further.

What are false positives?

False positives are OONI Probe test results (flagged as “anomalous”) which incorrectly indicate the presence of network interference (such as the blocking of a website or app).

When measuring the accessibility of websites, OONI Probe compares the results from your network with the results from a non-censored network. If the results don’t match, then the OONI Probe test result in question is flagged as an “anomaly”, indicating potential network interference. Many of these anomalies are in fact cases of network interference, while some may be false positives.

Why do false positives occur?

False positives can occur due a number of reasons.

Below are some reasons which may trigger false positives in website testing:

When running the OONI Probe instant messaging tests (WhatsApp, Facebook Messenger, Telegram), false positives may occur when the instant messaging app vendor makes changes to their infrastructure that affect how our tests run.

When running the OONI Probe middlebox tests, false positives may occur due to issues with the OONI Probe backend infrastructure.

When running any OONI Probe test, false positives may be caused by software bugs which are triggered by your particular device and network configuration.

How can I distinguish false positives?

Distinguishing false positives can often be tricky, even for engineers. It requires examining the network measurement data carefully, having a good understanding of how OONI Probe tests work, analyzing the data over a long period of time (to check whether the tested resource consistently presents the same anomalies on the same network), and evaluating and ruling out other possible reasons that could have triggered the anomaly (for example, by checking the global failure rates of a site).

As part of the OONI Partnership Program, we offer data analysis support to the human rights organizations that we collaborate with. All OONI data and methodologies are openly available with the hope that other data analysis will support communities as well.

We encourage you to reach out (via email or Slack) if you’re unsure of a measurement and planning on using it (for example) as part of reporting.

In general, we recommend looking at results over a timeline, rather than individually (unless if they are tagged as “confirmed”). For example, if you observe that a tested website presents the same anomaly (e.g. DNS tampering) every time it is tested on a specific network in a country, it’s more likely the case that access to it is being interfered with. If, however, a single measurement (for example) presents a TCP anomaly, but all other measurements testing that website on the same network were successful, it’s likely the case that that TCP anomaly is a false positive.

How can I check results from other OONI Probe tests?

You can filter OONI Explorer to find results from other OONI Probe tests through the following steps:

  1. Click on “Search” (top right corner)

  2. Optional: Select a country via the “Country” drop-down menu on the left

  3. Select an OONI Probe test via the “Test Name” drop-down menu on the left

  4. Optional: Select “Anomalies”

  5. Click “Filter Results”

Please interpret the “anomalous” results with caution, as they may contain false positives.

Why doesn’t my country have any recent measurements on OONI Explorer?

OONI Explorer automatically publishes the test results (measurements) of OONI Probe users in near-real time, within minutes of tests having been run.

If there are no recent measurements from your country, that means that:

You can contribute measurements by running OONI Probe in your country. The easiest way to run tests is through the OONI Probe mobile app for Android and iOS.