Internet Censorship Around the World: How Blocking Works

Additional resource for the lesson “Internet Censorship: A Global Reality” — Online Anonymity course

Internet censorship is not a single switch that some countries flip. It is a set of techniques, from a wrong answer in the internet’s address book to a network switched off entirely, used in different ways and for different reasons around the world, including in Europe. This resource explains how blocking works, how widespread it is as of November 2026, and how independent researchers measure it, so that a page that will not load becomes something you can understand rather than guess at.

A. Why this matters

In this course, privacy means deciding what others know about you; anonymity means being able to act without what you do being linked back to who you are. Censorship might seem a separate subject, about what you are allowed to read rather than who you are. In practice the two meet at one point: the network in between.

To block a site, a network has to recognise your request for it. The same visibility that lets a provider refuse a request also lets it notice who made it. And the tools people use to reach blocked content can themselves be noticed. Knowing how blocking works is therefore part of knowing what your connection reveals.

You do not need to live under heavy restrictions for this to be useful. If you travel, or a news site suddenly stops loading, the same few ideas apply.

What the sources say

Freedom House, which has published its Freedom on the Net report for sixteen years, opens the 2026 edition with a plain finding: “Global internet freedom declined for the 16th consecutive year.” Over its coverage period, June 2025 to May 2026, conditions worsened in 16 of the 38 countries assessed and improved in 8. Freedom House notes that it paused coverage of 34 countries in this edition, so the country count is smaller than in earlier years. The report describes governments “working to separate people in their countries from the global internet”, and records in Iran the longest nationwide shutdown in the report’s history.

Access Now, a digital rights organisation, and the #KeepItOn coalition documented at least 313 shutdowns in 52 countries during 2025, up from 304 in 2024. Its annual report also counts a record 94 blocks of individual platforms in 40 countries.

Europe has its own, lawful form of blocking. In 2014 the Court of Justice of the European Union ruled that “an internet service provider may be ordered to block its customers’ access to a copyright-infringing website.” The Court added conditions: a fair balance between the rights involved, including “the freedom of information of internet users”, and measures that do not unnecessarily stop people reaching lawful information.

The Electronic Frontier Foundation (EFF), a digital rights organisation, explains the techniques in its Surveillance Self-Defense guide. The Open Observatory of Network Interference (OONI), which develops free and open source measurement software, publishes its measurements as open data.

B. Key concepts: how internet censorship works

Six ideas, from the most common techniques to how researchers tell real blocking from an ordinary fault.

DNS blocking: a wrong answer from the address book

When you type a site’s name, your device asks a DNS resolver (a kind of address book, usually run by your internet provider) for the number of the server behind it. The EFF explains that a provider can set up its resolver to give “an incorrect answer, or no answer” for a blocked site. OONI adds that some networks go further and inject a fake answer into the reply.

Why it matters to you: The site has not disappeared; the address book has been told not to give it out. It also means the network sees each site name you look up, unless your lookups are encrypted.

IP blocking: refusing to connect to a server

Every server has an IP address, a number that identifies it on the internet. A network can keep a list of addresses it refuses to connect to. OONI points out the side effect: “blocking an IP address will result in blocking all of the websites hosted on that IP”, which can include sites nobody meant to block.

Why it matters to you: Overblocking is a real cost. A page that fails to load may be collateral damage rather than the intended target, which is one reason to check before drawing conclusions.

Keyword and site-name filtering

If traffic is not encrypted, the EFF explains, providers “can block web pages based on their contents”, looking for particular words. With HTTPS, the encrypted version of the web, “all of the content is encrypted except the name of the site.” A network can still block a whole site by its name, a technique OONI calls SNI-based filtering, but it cannot read which page you open or what it says.

Why it matters to you: HTTPS narrows what a network learns about you to the name of the site. That protects your privacy and limits the most detailed kind of filtering, though it does not stop a site being blocked by name.

Throttling and platform blocks

Not all censorship is a clean block. The EFF notes that providers “can selectively throttle (slow down) different types of traffic”, so a video service or messaging app becomes unusable rather than unreachable. The EFF adds that slowing is harder to identify and easier to deny. Blocking a single platform, such as one social network or messaging app, sits in between.

Why it matters to you: A slow or patchy app is usually just a bad connection. When the same service is slow for many people in one place at the same time, and others are not, it may be something else. Measurement data helps tell the two apart.

Internet shutdowns

At the far end, a network is switched off. The EFF describes how a shutdown “can involve physically unplugging network infrastructure, like routers, network cables, or cellular towers.” Shutdowns can cover a whole country, one city or only mobile data, and Freedom House records some lasting weeks or months.

Why it matters to you: A shutdown affects everyone in the area, whatever they wanted to read: messages to family, work, emergency information. That is why it is counted separately from blocking individual sites.

Block pages, anomalies and evidence

Sometimes a blocked site shows a notice page instead. OONI calls this “the only form of internet censorship that clearly notifies internet users of the censorship.” Most blocking is silent.

When OONI Probe, its free measurement app, finds signs of interference, the result is marked as an “anomaly”, and OONI is explicit that an anomaly “might be a false positive.” Only website blocking that matches a known fingerprint, such as a recognised block page, is marked as confirmed.

Why it matters to you: One failed page is not proof of anything. Researchers look at many measurements together over time, and so can you. Seeing it that way keeps your conclusions calm and accurate.

C. A practical example: Luca’s trip abroad

Luca is 36, lives in Milan and travels for work. On a recent trip, a news site he reads every morning would not load on the hotel Wi-Fi or on his phone’s mobile data. A messaging app he uses with a friend kept stalling, while another worked normally. At home, months earlier, he had once seen a notice page instead of a streaming site, explaining that access had been disabled following an order.

He was not alarmed, but he wanted to know what he was looking at. Was the hotel network faulty, the site down, or was it blocked in that country? He did not want to install something on impulse without knowing what it might signal to the network he was on.

What changed when Luca looked at the data

Back in his room, he did the exercise in section D, reading published data rather than running any test:

• In OONI Explorer, OONI’s open data site, he filtered by the country he was visiting and found many anomalies for the news site across several networks over the past weeks, and a few for the messaging app. Many measurements over time, not one failed page, were what made the pattern meaningful.
• On IODA, a Georgia Tech research project that tracks internet outages, he saw no drop in connectivity for the country: the network was up, so this was not a shutdown.
• He noticed that the notice page he had once seen at home was the visible kind of blocking, and that the news site abroad was the silent kind.

He made two decisions. Before his next trip, he would spend ten minutes reading the data for his destination. And he would read section E5 of this course on Tor Browser before deciding whether it suited him, rather than reaching for the first tool an app store offered. He did not try to get round anything that evening: understanding came first.

D. Try it yourself: look up censorship data for your country (20 minutes)

Five short steps. You only read published data: nothing here requires installing software, and nothing tests or bypasses any block.

Step 1 — Write down what you have noticed (3 minutes)

• Note any site or app that has failed to load for you at home or while travelling, and where you were.
• Note any notice page you have seen saying access was blocked or disabled.
• If you have noticed nothing, that is fine. Choose your own country and one country you might visit.

Step 2 — Read your country’s measurements in OONI Explorer (6 minutes)

• Open OONI Explorer and use the Countries section, or the search page with the Country filter, to choose your country, then select Filter Results.
• Look for sites or apps with repeated anomalies across several networks and dates, not single results.
• Look for any marked as confirmed: these matched a known block page.

Step 3 — Check connectivity on IODA (4 minutes)

• Open the IODA dashboard and look up the same country.
• Its outages timeline shows events at country, region and network level. A sharp drop across signals suggests an outage, which may be technical or deliberate.
• Compare: a site blocked while the network is up is a different thing from a network that is down.

Step 4 — Read the bigger picture (4 minutes)

• Look for your country in Freedom on the Net 2026. If it is not covered this year, note that: coverage was reduced, and absence says nothing either way.
• Read the Access Now summary of internet shutdowns in 2025 and see whether your region is mentioned.

Step 5 — Write one sentence and one decision (3 minutes)

• Complete: “In my country, the most common form of restriction appears to be ___.”
• Choose one: set your browser to use HTTPS only, check the data before your next trip, or read section E5 on Tor Browser.

One finding you understand is worth more than a long list of worries.

Already covered in the Online Privacy course

What Does a VPN Hide? Privacy, Trust and Choosing a Provider
It covers what a VPN hides, from whom, and how to judge a provider you would be trusting; this resource explains how blocking itself works and how it is measured, without recommending any tool to get round it.

E. Videos, articles and further resources

Reports and legal sources first, then a digital rights guide and the measurement projects used in the exercise. All in English.

Reports and legal sources

Freedom House — Freedom on the Net 2026: Seismic Shifts on the Global Internet
The annual assessment of internet freedom, covering June 2025 to May 2026, with country reports.
https://freedomhouse.org/report/freedom-net/2026/seismic-shifts-global-internet

Access Now — Rising and resisting in the darkness: internet shutdowns in 2025
The #KeepItOn coalition’s figures on shutdowns in 2025, with a link to the full annual report.
https://www.accessnow.org/press-release/rising-and-resisting-in-the-darkness-internet-shutdowns-in-2025/

Court of Justice of the European Union — Press release No 38/14: An internet service provider may be ordered to block its customers’ access to a copyright-infringing website
The 2014 ruling on blocking orders in the EU and the balance with internet users’ freedom of information.
https://curia.europa.eu/jcms/upload/docs/application/pdf/2014-03/cp140038en.pdf

Digital rights guides

Electronic Frontier Foundation — How to: Understand and Circumvent Network Censorship
A clear guide to how DNS and IP blocking, filtering, throttling and shutdowns work; it also covers circumvention tools and their risks, whose legality varies by country.
https://ssd.eff.org/module/understanding-and-circumventing-network-censorship

Measurement projects

OONI — Interpreting OONI data
How DNS, IP, HTTP and SNI-based blocking show up in measurements, and why anomalies need to be read together.
https://ooni.org/support/interpreting-ooni-data/

OONI — User Guide: OONI Explorer
How to search open censorship measurements by country, and what “anomaly”, “confirmed” and “failure” mean.
https://ooni.org/support/ooni-explorer

OONI — User Guide: OONI Probe Desktop App
What the OONI Probe app tests, and the risks of running it to read before installing.
https://ooni.org/support/ooni-probe-desktop

IODA (Georgia Tech) — Unlocking Connectivity Insights: Georgia Tech’s Revamped IODA dashboard
How the Internet Outage Detection and Analysis dashboard shows outages by country, region and network.
https://ioda.inetintel.cc.gatech.edu/reports/unlocking-connectivity-insights-georgia-techs-revamped-ioda-dashboard/

Links checked in November 2026. If an address changes, searching for the title on the organisation’s site usually finds it.

F. The Cyber Welfare Framework: Skills, Awareness, Secure Behaviour

This resource sits on the Awareness pillar at level FL2 – Beginner: understanding how blocking works before deciding what, if anything, to do about it.

Skills

• Telling DNS blocking, IP blocking, filtering, throttling and shutdowns apart.
• Reading OONI Explorer measurements for a country, and telling an anomaly from a confirmed block.
• Checking on IODA whether a network is up or down.

Awareness

• Understanding that blocking depends on what a network can see of your connection.
• Knowing that HTTPS hides which page you read, but not the name of the site.
• Recognising that lawful blocking orders exist in Europe too, with conditions set by courts.

Secure Behaviour

• Checking published data before travelling, rather than guessing when something fails.
• Keeping HTTPS on, so that a network learns as little as possible about what you read.
• Reading the risk notes of any measurement or circumvention tool before using it.

G. Questions to sit with

• When a site fails to load, how quickly do you decide why, and what would change your mind?
• Where would you draw the line between a blocking order you consider legitimate and one you do not, and who should decide?
• If a network can see which sites you try to reach, what else could it learn about you from the same view?

H. What to do now

The recommendations (R) and security measures (MS) from the Cyber Welfare database that apply most directly here.

1. Limit what the network sees

• R9 — Browse only over HTTPS: the network then sees the name of the site, not the page you open or what it says, which also limits filtering by keyword.
• Before you travel, spend a few minutes with the published data for your destination, so that a failed page is less of a mystery.

Minimum commitment: today, check whether the browser you use most is set to use HTTPS only.

2. Look further, in proportion

• If you want to run OONI Probe yourself, read its risk section first: OONI states that running it “may be risky for some people in some countries”, and that it “is not a privacy tool”. Reading published data on OONI Explorer does not involve running any test.
• Rules on using such tools vary by country. If you are thinking about tools to reach blocked content, read section E5 of this course on Tor Browser before choosing, and check what is lawful where you are.

Minimum commitment: this week, look up one country, your own or your next destination, in OONI Explorer.

In short

• Internet censorship uses a handful of techniques: DNS and IP blocking, filtering, throttling, platform blocks and shutdowns.
• As of November 2026, Freedom House reports a 16th year of declining internet freedom, and Access Now counted at least 313 shutdowns in 2025.
• Most blocking is silent, and one failed page is not proof: measurement projects read many results together.
• Blocking works because the network sees where you go. HTTPS narrows that view to the site name, and section E5 looks at Tor Browser.

Related resources in this course

• Mass Surveillance Explained: Who Collects Data and How
• Protest Surveillance: What It Means for Your Rights
• Age Verification and Anonymity: What Changes for You
• What Is Tor? How Tor Browser Protects Your Anonymity

Discover more companion resources from the online courses of the Protect Your Digital Privacy programme.