How Iran Cut Off the Internet Nationwide, Which Countries Can Do It?

During the 12-day war with Israel, Iranians experienced a near-total internet blackout that lasted for several days, according to The Conversation . Domestic network services, including mobile services, were repeatedly disrupted. The Iranian government claimed that it ordered the shutdown to ensure cybersecurity.

“Iran has really, really tight control over information,” Marwa Fatafta, policy and advocacy director at the Berlin-based digital rights group Access Now, said in an interview with The Associated Press . “Their goals are pretty clear.”

Shutting down the entire Internet in a country is considered a serious act, restricting people's right to communicate and access to information, especially in times of conflict.

In countries where networks and telecommunications services are privately operated, the government often exerts control through laws or administrative regulations, such as age restrictions on adult content. Iran, meanwhile, has spent years building up the capacity to directly control its domestic telecommunications infrastructure.

There have been internet outages in Iran during events such as the September 2022 protests. Photo: Reuters .

So how can a country tightly control access to the Internet? And could this happen anywhere else in the world ?

How does a country “cut off” the Internet?

The Internet includes applications, online services, and websites. There are many ways to control access to the Internet, but there are generally two ways a country can block access for its citizens.

The first is to physically disconnect the hardware, which means turning off the Internet connection points entering the country, which can be thought of as “pulling the plug.” This allows for easy restoration of connectivity when the government wants, but the impact is widespread. The entire country, including the government, will be unable to access the Internet unless they have their own connection system.

The second way is to block using software and network configuration. Every device connected to the Internet such as a computer or phone has an IP (Internet protocol) address, for example 77.237.87.95 is an IP assigned to a network operator in Iran.

However, instead of remembering a series of numbers, people use domain names to access. The connection between IP and domain names is coordinated by the DNS (Domain Name System). Governments can manipulate the DNS system to prevent people from accessing Internet services by falsifying the IP addresses associated with domain names.

Technicians monitor data flows in the control room of an Internet service provider in Tehran in 2011. Photo: Reuters .

Similarly, it interferes with the flow of Internet data. IP allows devices to send and receive data through networks controlled by service providers. These networks rely on the Border Gateway Protocol (BGP), which can be thought of as a system of traffic signs that help route data around the world.

If a government requires domestic carriers to remove their BGP routes from the global system, domestic devices will not be able to access the Internet, and conversely, the outside world will not be able to “see” that country on the Internet.

Many countries have restricted or completely cut off the Internet in response to major events.

A recent example is the widespread outage in Bangladesh in July 2024, during student protests over civil service recruitment policies. In 2023, Senegal also restricted the internet in response to protests after a political leader was convicted. In 2020, India conducted a lengthy internet shutdown in the disputed region of Kashmir. In 2011, Egypt also shut down BGP in response to political unrest.

These examples show that if a government wants to shut down the Internet, it can do so without requiring any special technical skills.

Can I connect after being "disconnected" from the Internet?

Virtual private networks (VPNs) have long been used to bypass internet censorship in countries with heavy controls, and remain a useful tool. However, there have been recent signs that Iran is cracking down on VPN use.

Fire and smoke rise from an Israeli attack on the Sharan oil depot in Tehran on June 15. Photo: Reuters .

VPN also doesn't work when the Internet is completely down at the hardware level or BGP is blocked.

In these situations, the most viable solution is satellite Internet, which is independent of traditional network infrastructure. Satellite Internet is especially useful in remote areas where cable infrastructure is either unavailable or impossible to build. Even if traditional wired or wireless connections are lost, satellite services like Starlink, Viasat, HughesNet, and others can still deliver Internet to user devices from satellites orbiting the Earth.

To use satellite internet, users need a dedicated antenna from a service provider. In Iran, Elon Musk’s Starlink has been activated during the outage. According to multiple independent sources, there are currently thousands of Starlink devices operating secretly in the country.

Source: https://znews.vn/iran-da-cat-internet-ca-nuoc-the-nao-nhung-nuoc-nao-lam-duoc-post1563575.html