Hours before the major blackout that knocked many sites offline yesterday, Cloudflare issued a clear message directed at Spain: if a website protected by their services is experiencing access issues from Spanish territory, the company wants this to be measured and documented using an application called OONI Probe.
The appeal, posted on their official X social media account, was aimed at both individuals and businesses using Cloudflare to protect and accelerate their websites, provided they are located in Spain. The question was direct: “Has your website experienced unexpected access problems in Spain? Help us find out why.”
Although the message did not explicitly mention LaLiga, the context is clear: for months, Cloudflare’s Content Delivery Network (CDN) has suffered IP address blocks ordered by Spanish telecom operators on match days to combat illegal streaming. These blocks target illicit services but can also affect completely legitimate websites sharing infrastructure.
In response, the company appears to be taking an additional step: requesting their own clients to generate technical evidence that demonstrates when a website becomes unavailable due to external intervention, not server failure.
A tool to measure censorship and network interference
The tool recommended by Cloudflare is not their own but an independent project: OONI Probe. It is software developed by the Open Observatory of Network Interference (OONI), an organization that since 2012 has been documenting censorship, filtering, and traffic manipulation attempts worldwide.
OONI is supported by dozens of digital rights, tech, and academic organizations. Among them is the Internet Society, one of the most vocal critics of IP address blocks, which they say “undermine fundamental properties of the Internet” by affecting not only the targeted content but also everything sharing the same network pathway.
OONI Probe is available as a desktop application and command-line tool for computers, along with mobile apps. Any user can install it and run tests on specific websites to check for signs of filtering.
What does OONI Probe detect when a website “disappears”?
Cloudflare promises that OONI Probe results are anonymous and help to “measure website blocking in your region.” But what exactly does the app do?
When entering a web address in OONI Probe, the tool performs a series of technical tests to detect common blocking methods:
- DNS manipulation: Checks if DNS servers are returning false responses or redirecting users elsewhere.
- TCP connection blocking: Analyzes whether the connection is systematically cut before reaching the server, a typical behavior in some filtering systems.
- HTTP request interception: Verifies if web requests are intercepted or altered by intermediaries.
According to available information, in Spain, operators mainly apply TCP connection and HTTP request blocking on football match days—techniques that OONI Probe can identify.
All test results are stored on OONI’s servers and can be reviewed later through their analysis platform. This allows verifying whether a certain domain fails only for an individual user or consistently appears blocked from multiple networks and regions—indicating intentional interference.
A global “radar” that documented the Catalan referendum case
OONI is not a recent experiment but a tool that has been documenting censorship attempts in dozens of countries for over a decade. One well-known example in Spain was its 2017 report on blocking sites related to the Catalan referendum of October 1st.
In that case, data collected by users running OONI Probe proved that access to various websites associated with the referendum was systematically interfered with by operators. Patterns of DNS manipulation and interception techniques were identified, ruling out the possibility of technical issues alone.
Now, it seems Cloudflare wants to replicate that model: if enough web administrators in Spain measure their sites’ connectivity with OONI Probe during access issues, the resulting data could be used to demonstrate widespread blocks against their infrastructure.
A new front in the legal battle over blocks in Spain
The public call to gather evidence comes at a sensitive time for Cloudflare in court. In March, Spanish courts rejected nullity actions filed by the company itself and by security conference RootedCON, seeking to overturn the ruling authorizing IP blocks. The judge found that sufficient harm to third parties had not been proven to justify nullification.
The case is still ongoing at the Constitutional Court, where it is being assessed whether the current blocking system respects users’ and website owners’ fundamental rights, especially when they may be affected without law infringements.
Within this context, systematic measurements with OONI Probe could play a crucial role. If data shows that a significant number of legitimate sites hosted through Cloudflare appear inaccessible from Spain during certain times linked to football matches, the company could have stronger grounds to argue that the blocks are disproportionate and harm innocents.
How affected websites can contribute
For a media outlet, Cloudflare’s call might sound highly technical, but the steps to help are fairly straightforward:
- Identify the problem
If a website using Cloudflare works fine from other countries but repeatedly fails in Spain—especially on certain days or times—there is likely some form of filtering occurring. - Install OONI Probe
Download the app on a computer or mobile device. After installing, open it, enter the affected website’s address, and run the test. - Repeat from different connections
Running tests through various networks (fiber, mobile, Wi-Fi) helps determine if the blocking is limited to a provider or more widespread. More data makes pattern detection easier. - Save and review results
While data uploaded to OONI is anonymous, website owners can keep reports and screenshots for documentation and, if needed, present them as evidence to their provider or regulators.
For individual users, the process doesn’t change whether the site is accessible or not; but it transforms a “mystery” into measurable, comparable data that can feed public debates.
Beyond football: what this case says about the future of the Internet
The underlying conflict is not just between a football industry trying to curb piracy and an infrastructure giant defending its network. It’s about the kind of Internet society wants to build.
When IP blocking is ordered at the operator level, it doesn’t just cut off access to a specific service; it can also affect everything traveling through that same channel. In a world where thousands of websites share infrastructure, the risk of “collateral damage” is high.
Therefore, projects like OONI and initiatives like Cloudflare’s current call point to a broader debate:
- What tools are used to combat piracy and other online crimes?
- Who ensures that measures are proportional and do not impact legitimate content?
- How can citizens and businesses verify whether issues are due to temporary failures or intentional blocks?
Cloudflare’s appeal to its clients in Spain—encouraging them to measure and document access disruptions with an independent app—is a way of shifting some of that oversight to users themselves. From now on, each measurement adds a piece to the map of how, when, and where access is restricted. This map could be key in shaping society’s vision of the Internet’s future.
References: Banda Ancha, Redes Sociales, Twitter X, and OONI Probe