What Is Internet Censorship and How Does It Affect Access to Information?
A plain-English explainer on internet censorship — how it works, who it affects, and why it matters for access to verified information.
What Is Internet Censorship?
Internet censorship is the deliberate control or suppression of what can be accessed, published, or communicated online. Governments, internet service providers (ISPs), and other authorities use technical and legal mechanisms to restrict information flow.
Censorship takes many forms: blocking websites, filtering search results, throttling or shutting down networks entirely, and surveilling communications. The goal is typically to control the narrative, suppress dissent, or maintain political stability — but the effect is always the same: reduced access to verified information.
How Censorship Works Technically
Common technical methods include:
- DNS blocking — preventing domain name resolution so websites cannot be reached
- IP blocking — dropping traffic to specific server addresses
- Deep packet inspection (DPI) — analyzing packet contents to identify and block specific protocols or applications
- Internet shutdowns — disabling network infrastructure entirely during crises or elections
Each method has different implications for users and requires different countermeasures. Understanding how censorship works is the first step toward building resilient access tools.
Impact on Information Access
When censorship is active, communities lose access to:
- Independent news and journalism
- Emergency alerts and public safety information
- Educational resources and documentation
- Communication with family and colleagues abroad
This is why Open Signal Foundation builds tools for both online resilience and offline information distribution through projects like FreeWave and IranVPN.
What You Can Do
- Learn about censorship in your region through our Research Hub
- Support open-source internet freedom tools through donations
- Never share operational circumvention details publicly if you work on access tools
FAQ
Related pages
Related Articles
How Digital Safety Changes Under Censorship
Digital safety practices that matter more when internet censorship is active — risk assessment, privacy basics, and informed decision-making.
Iran Internet Censorship: A Plain-English Overview
An overview of how internet censorship works in Iran — DNS blocking, DPI, protocol filtering, and the impact on information access.
What Is a QR Broadcast?
QR broadcasts encode digital content into scannable video frames, enabling offline information distribution without internet connectivity.