The letter appears to be an order from Andrei Chernenko, Russia’s deputy digital minister, demanding that Russian state-owned websites and online portals beef up their security by Friday this week.

It tells them to move their hosting to Russian services if they are currently using foreign hosting services, and to scrub their web pages of all JavaScript code that has been downloaded from foreign sources; JavaScript is one of the main web programming languages, and the document cites banners and visit counters as examples of the sort of page elements that might need to be removed.

It includes one instruction that particularly raises eyebrows: Russian state-owned web services must by Friday make sure they have switched to domain name system (DNS) servers located on Russian soil. The global DNS is what the internet uses to translate web addresses like “fortune.com” into the alphanumerical internet protocol (IP) addresses that computers use to communicate (which, in Fortune’s case, is “2a02:8109:b6bf:45c0:10:18ff:fe41:4794.”)

In other words, the DNS is what lets humans use the web easily, around the world. So the document raises the question of whether Russia intends to cut itself off from this system—and effectively the global internet, too.

Cyberattacks

Chernenko’s department said on Monday there were “no plans” to disconnect Russia from the global internet, telling the Russian news agency Interfax that the letter was all about protecting Russian websites from foreign cyberattacks.

According to Alena Epifanova, a Russian cyber-policy expert at the German Council on Foreign Relations, this explanation is quite plausible. “To me, it looks like a normal, reasonable document against the cyberattacks which we observe,” she told Fortune on Monday.

Indeed, Russian online services have been heavily targeted in recent cyberattacks, partly thanks to Ukraine’s enormous volunteer “IT army” and partly because the online hacker collective Anonymous has also declared a “cyber warfare campaign” against Putin and his allies.

“Pretty well every single website in Russia has gone down in the last week, at some stage or another,” said Rafal Rohozinski, principal at the research and strategy outfit SecDev Group. “There’s a lot of concern about that.”

But there’s a good reason why some suspect a disconnection is in the works.

In 2019, Vladimir Putin’s government made a “Sovereign Internet” push that expanded Kremlin control over the country’s online infrastructure, while purporting to be all about protecting the Russian internet from security threats. Apart from centralizing control of Russia’s telecommunication systems and forcing internet service providers to plug surveillance and site-blocking equipment into their networks, the government ordered the unprecedented creation of an independent Russian DNS.

Many suggested at the time that the move looked a lot like preparation for keeping the Runet operational in the event that it becomes isolated from the global internet. Iran has also been making similar preparations for online isolation—a far more drastic step than even China, with its notorious “Great Firewall” censorship and surveillance apparatus, has taken.

Now, amid as-yet-unsubstantiated rumors of Putin preparing to declare martial law, some see this as a moment of truth for the Runet.

‘Not 100% prepared’

Epifanova said she does not believe Russia is ready to switch exclusively to its own domain name system. Under the Kremlin’s 2019 plan, the Russian DNS was supposed to be fully up and running by the start of 2021—but it wasn’t, and despite tests of the system, she says it probably still isn’t.

Fending off government pressure that has stepped up in the past month, some Russian internet service providers still haven’t connected their networks to the Russian DNS even though they are getting fined for not doing so, Epifanova said. “They know it might cause disruptions in the infrastructure, and also they know that this system is not 100% prepared,” she explained.

Epifanova also suggested Russia might be worried about international internet authorities limiting Russian state organizations’ access to secure internet connections.

As it happens, Ukraine did last week ask ICANN, the U.S.-based group that runs the global DNS, to cut Russia off from the system and to revoke its top-level domains, such as “.ru.” ICANN refused, saying its job was to “ensure that the internet works, not for its coordination role to be used to stop it from working.”

“Russia is still not prepared to decouple itself [from the global internet] completely,” Epifanova said. “The whole Russian economy is based on the global internet—it’s not Iran or China. If disconnected, we could expect a major collapse in the Russian economy.”

Putin’s main internet-related concern right now is blocking Russians from seeing real news coming in from Ukraine, and to push his official narrative about Russia’s “special operation” in the country, she added. For that, she said, “they are well prepared”—witness Russia’s recent blocking of Facebook and Twitter, among many other examples.

Outside forces

According to Rohozinski, there is less chance of Russia disconnecting itself from the global internet than being cut off by others.

A few days ago, the global internet service provider Cogent said it would no longer connect its Russian customers, such as Rostelecom, to its core infrastructure for carrying internet traffic around the world. The company said it didn’t want its network to be used for “outbound cyberattacks or disinformation,” but Rohozinski noted that, thanks to sanctions, Russian ISPs may be finding it difficult to pay international providers such as Cogent.

“It’s curious that it’s not geopolitics forcing Russia off the net, it’s purely economics,” he said.

However, while Russia has so far not launched the “cyber Pearl Harbor everybody expected to see at the start of this invasion,” Rohozinski said, it is still possible that Russia is preparing cyberattacks on Western critical infrastructure—and preparing to be hit back.

“I don’t think we can exclude the fact that cyberspace may become a bigger part of this conflict in the coming weeks,” he said. “Russia hunkering down behind its digital defenses may be one way it’s taking a defensive posture while getting ready for a much more offensive posture as well.”