Access to the internet is gradually being restored in Iran after an unprecedented five-day shutdown that cut its population off from the rest of the world and suppressed news of the deadliest unrest since the country’s 1979 revolution.

The digital blackout that commenced last Friday is part of a growing trend of governments interfering with the internet to curb violent unrest, but also legitimate dissent.

The internet-freedom group Access Now recorded 75 internet outages in 2016, which more than doubled to 196 last year. “The tactic has been around for a while, but the rate at which it is being applied now is extremely alarming,” says Berhan Taye, of the UK-based organisation.

But Iran’s restriction of the internet this week was something more sophisticated and alarming, researchers say.

Iranians were cut off from the global internet, but internally, networks appeared to be functioning relatively normally. The Islamic Republic managed to successfully wall its citizens off from the world, without taking down the internet entirely.

“It’s the birth of a new kind of internet and we’re watching it go live in our charts,” says Alp Toker, the director of Netblocks, a group that tracks internet disruption.

Iran has been honing its ability to restrict the internet for more than a decade, researchers say. This week’s digital blackout showed they are getting closer to perfecting it.

Internet penetration and complexity has vastly grown in Iran over the past decade, but the country’s users still connect to the global network through just two gateways. Both are controlled by the regime, and can be blocked when it chooses.

At the same time, the Iranian government has been working to develop the so-called “halal net”, a closed-off version of the internet similar to China’s “great firewall”. Iran has been pressuring businesses to shift their operations inside the country on to what it calls the National Information Network, which now boasts its own banking platforms, industrial services and messaging apps – ones that activists believe are closely surveilled by authorities.

Iran’s rulers have an unlikely ally in their efforts to ringfence the country’s internet, says Amir Rashidi, an Iranian cybersecurity researcher. The sanctions imposed on Iran in May 2018 as part of Donald Trump’s maximum-pressure campaign have led US-based internet-service firms such as Amazon Web Services and Google Cloud to cancel accounts with Iranian companies.

Many Iranian tech firms have been left with no option but to use the Islamic Republic’s internal network and infrastructure instead. The Trump sanctions have actually made it easier for Iran to seal its citizens off from the global internet, he says. “Iranians are trapped between the Iranian and the US governments.”

The last time Iran attempted to choke off access, during unrest in January 2018, it was forced to open connections again after just 30 minutes, Rashidi says.

“It was a disaster,” he says. “Nothing was working: all the government offices, hospitals, financial services were gone.”

This time, it appears to have gone more smoothly: two sources able to monitor internet traffic inside Iran confirmed to the Guardian there was no significant disruption, indicating hospitals, financial software and even ride-sharing apps were still able to function, even as Iranians were unable to connect to websites such as Google.

“They hadn’t tested it before, so they’ve discovered a lot of things do need access to the outside world,” says Mehdi Yahyanejad, a technology activist and researcher.

“Many private companies are still in operation, but at the same time I’ve heard some hospitals can’t run their payment systems so people have had to pay in cash. But over time they are going to perfect it, now that they’ve seen how useful it can be,” he says.

Other authoritarian governments are pursuing a similar path. This month, Russia implemented a new law requiring ISPs to install equipment better able to identify the source of web traffic, as part of a strategy to one day be able to completely re-route the Russian internet through state-controlled data points.

Should Iran’s feat this week be judged a success, others who have shown an eagerness to control the internet may seek to follow in its footsteps, Toker says.

“Regimes around the world will be watching very closely both the public response and the response of the international community,” he says. “If it turns out this is feasible to implement, they will see there is no political cost.”

The Iranian president, Hassan Rouhani, has now declared victory over the protest movement. A nation of 81 million people was effectively silenced. Regimes elsewhere will be taking notes.