It's a smart thing to do (to have such a plan) even if no cyberwar ever takes place. There are so many possible scenarios of what could go wrong and having autonomous but functioning internet is absolutely necessary.
It's kind of a stupid thing to do. Well, the excuse at least. Only people who don't know what BGP even is would buy the excuse. Any connected fragment of the internet can continue functioning autonomously anyway. The majority of traffic inside any country is already not going outside, and the internal segment would not break if the outside routes suddenly disappeared.
> China (and others) can also simply intercept all udp traffic to port 53.
Which is why DNSSEC (to prevent MITM tampering) and DNS encryption technologies such as DNScrypt or DNS-over-TLS/HTTPS become ever more important to be widely deployed.
So wouldn’t it be reasonable to test what happens when it can’t reach its upstream servers? I assume Russia will need to provide some way of DNS record changes still working. It could be they intercept/replace 8.8.8.8, or they intercept the upstreams, but whatever it is I can see why they would want to test it first.
Not that I agree with the ultimate reasons for doing this exercise — mass filtering and surveillance — just speaking to the technical merits of why a test would be done.
What's the value in protecting the domestic internet from a cyber attack? Critical national information services absolutely, but if Reddit goes down, it's not a matter of national emergency. The conceit COULD be for disseminating information, but a text message system would make more sense in that regards, plus good old fashioned TV and Radio.
The "domestic internet" is part of a collection of infrastructure systems that need to properly work to keep order in place.
For a more blatant example take a look at the dependency of US emergency services on private communication companies like Calif. wildfire fighters having their communications disrupted because Verizon throttled their bandwidth.
At first sight a mildly interesting anecdote, but in reality, it's a massive flaw in the US's approach to infrastructure. If anybody really wanted to "cyber" the US they would only need to attack the private communication providers, like Verizon, and will not only take down the public spread of information/communication, but also completely disrupt the civilian emergency response forces attempting to react to whatever else the adversary might be attacking with, for an attacker it's a win-win.
Sure, the US military has its own hardened communication, but all the rest of the US American society? They will be left out in complete information and communication blackout.
I'm old enough to remember this happening 17 and a half years ago.
Two airplanes had crashed into the Twin Towers in New York, and word starting coming in of another plane crashing into the Pentagon building. Talk of terrorism spread, and American airspace was shut down, and another airplane crash was reported. All the news websites were down, except for Chips & Dips, which had disabled images and was mostly text anyway.
Actually, the site had already changed its name by then. I sometimes see some usernames here that I remember from there.
And in the case of Russia shutting off the external connections, thus preventing any external news agencies from reporting, the Russian stock market would happily continue on?
Unlike the US and Europe, capital in Russia is largely stashed abroad, and the economy not especially dependent on the small amount of trade and information mediated by the domestic stock market.
A stock market is kind of an institutional miracle -- people who don't know each other come together in the form of corporations, and then borrow from other people that don't know them. In a place with less trust, such cooperation is less feasible.