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Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

gfw.report

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Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#161
post #2

Terrible, this is Internet curfew. It's not uncommon to imagine they'd shutdown Internet across border during any war (like against Taiwan).

> Terrible, this is Internet curfew. If you think this is bad... You can't even have a blog in China without authorization. It doesn't matter if you pay "AWS" for a machine. It won't open port 80 or 443 until you get an ICP recordal. Which you can only do if you are in China, and get the approval. It should also be displayed in the site, like a license plate. The reason "AWS" is in quotes is because it isn't AWS, the…

What about other protocols, could you run eg Gopher or NNTP? I guess IMAP could work as well.

Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#163

Earlier quoted context omitted.

I would not say "unambiguously" when it comes to natural languages. And no, "America" may have referred to the US when I was a kid and here in Central Europe we had Back to the Future type of shoes with the American flag, yeah, and I would not say unambiguously so. If someone says "America" to refer to a place, they really ought to specify if they want you to understand them.

I can't think of any English speaking countries in central Europe off the top of my head. "America" is short for "The United States of America" in English. That's its definition. I don't understand how people have difficulty with this concept.

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Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#164

Earlier quoted context omitted.

I would not say "unambiguously" when it comes to natural languages. And no, "America" may have referred to the US when I was a kid and here in Central Europe we had Back to the Future type of shoes with the American flag, yeah, and I would not say unambiguously so. If someone says "America" to refer to a place, they really ought to specify if they want you to understand them.

But America isn't a place. There's the America s , as in plural, referring to the continents of North America and South America. So America is unassigned, hence why we assigned it to the USA colloquially.

Just for the sake of it I checked Wikipedia.

> The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America. When viewed as a single continent, the Americas are the 2nd largest continent by area after Asia, and is the 3rd largest continent by population. The Americas make up most of the land in Earth's Western Hemisphere and constitute the New World.

Yeah, OK, not sure "America" refers to The Oh-So-Great United of America according to this. Guess what? You can find 10 in each direction. Specify. If you disagree with "one should specify", why down-vote? Baffling, baffling indeed.

Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#165

Earlier quoted context omitted.

No but something like WSPR or FT8 would. Needs a license though.

FT8 has such a small payload that you couldn't fit an emoji, much less an average English sentence. There's no authentication so anyone can pretend to be you. Traditional methods of verifying the sender (HMAC) would take so many hours to transmit that the physical propagation paths you're communicating through will probably collapse before you deliver the smallest verified message. If you need to communicate informat…

Agreed but if you're trapped in a war zone, time is one thing you have. And equipment for FT8 is simple to build yourself. It's also very difficult to trace. And you can take up some fields used for other stuff and convert them to data (like the sender). This would be illegal on amateur bands since it's required to identify oneself but again in a war situation this is less relevant since any covert communication will probably be forbidden anyway.

You do need a time source though. GPS is generally used for that but it doesn't need to be extremely accurate with FT-8 like with some other protocols.

I would imagine using it for a regular "I'm ok" message for the home front in such a situation using pre-arranged contents.

Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#166

Earlier quoted context omitted.

How do you propose users in China will magically get around a nation state injecting packets?

That's literally what VPNs are for. If you aren't aware: a Virtual Private Network creates a fully encrypted link between you and a remote node. So long as your encryption keys are secure, there's no way for anyone (even a global superpower) to listen to or intrude on that connection. There is no possible way to break into this connection, even with the entire planet's computing resources. From the outside, all you c…

Thanks for the reply. In order to connect to the VPN, your first call must be over https, from China, to the VPN. How does that circumvent the phenomenon in the article, where a nation state was injecting TCP to cause your connection to hang up, thus no VPN connection?

Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#167
post #140

Earlier quoted context omitted.

> Starlink connects you to the internet via a ground station in the country where you are registered Not true anymore. > and the antenna will also only operate in an approved zone (depending on your country and account type). You cannot use it in China. This is still correct.

They have a minor capability to do intra-constellation routing now but if they want to operate in China the authorities are going to demand all data be downlinked through Chinese downlink stations so they can do their monitoring.

I wasn't aware that China does this. I know India does too though, for this reason only Inmarsat is allowed there because they cooperate with the authorities (and I believe even that is subject to local licensing).

Though India doesn't have a great firewall so it's much less of an issue for foreigners visiting there.

Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#168
post #66

Earlier quoted context omitted.

No it does not. Against a huge state adversary like China it does not matter. They have satellites looking down so they can quickly locate any starlink users. And then ... The only thing that could bypass is GPS + laser links (meaning physically aiming a laser both on the ground AND on a satellite). You cannot detect that without being in the direct path of the laser (though of course you can still see the equipment…

The aim doesn't need to be that accurate. Laser beams diverge due to diffraction. You can't break the laws of physics - a non-divergent laser beam would need to be infinitely wide. A 1cm wide laser beam of 700nm light will have a divergence width of approximately asin(0.0000007/0.01) which is 0.004 degrees, which is 14 arcseconds, which is very easily aimable using off-the-shelf components. People get a tracking accu…

> However, this solution is going to stop working when a cloud drifts past.

Not really, because you'd be using a frequency that passes through clouds. A snow storm or hail is impenetrable, and there are weather events that cause a 1-2 second blackout, as well as cause refraction (which is mostly a challenge in reaiming the beam fast enough to compensate), but anything in the air is fine. Clouds, mist, ... But is aiming at a 1 arcsecond target moving across the sky at at least 1 degree per second from a normal (ie. moving) building really doable with "standard hobbyist telescope mounts" ?

I know 5 years ago we were still doing this with lasers on rockets toward planes, because planes can just keep their angle to a rocket essentially constant. I know there's experiments doing direct laser to satellite, no idea how well that works.

Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#169
post #50

Earlier quoted context omitted.

Starlink connects you to the internet via a ground station in the country where you are registered, and the antenna will also only operate in an approved zone (depending on your country and account type). You cannot use it in China.

> Starlink connects you to the internet via a ground station in the country where you are registered Not true anymore. > and the antenna will also only operate in an approved zone (depending on your country and account type). You cannot use it in China. This is still correct.

> Not true anymore.

It’s still true because in order to be operating in a country Starlink has to get approval from the Gov and if the Gov requires Starlink to have to connect through a ground station then they’ll either comply or not operate in that country

Re: Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025

#170
post #168

Earlier quoted context omitted.

The aim doesn't need to be that accurate. Laser beams diverge due to diffraction. You can't break the laws of physics - a non-divergent laser beam would need to be infinitely wide. A 1cm wide laser beam of 700nm light will have a divergence width of approximately asin(0.0000007/0.01) which is 0.004 degrees, which is 14 arcseconds, which is very easily aimable using off-the-shelf components. People get a tracking accu…

> However, this solution is going to stop working when a cloud drifts past. Not really, because you'd be using a frequency that passes through clouds. A snow storm or hail is impenetrable, and there are weather events that cause a 1-2 second blackout, as well as cause refraction (which is mostly a challenge in reaiming the beam fast enough to compensate), but anything in the air is fine. Clouds, mist, ... But is aimi…

You are correct in that most "hobbyist telescope mounts" are good for tracking stars at ~1 arcsecond, only where those stars don't move across the sky very quickly (up to 15 arcseconds/second). However, it is quite within the realm of "hobbyist" telescope mounts, albeit towards the upper end, to track orbital objects. I have seen an example of a telescope mount tracking the international space station to get good images, and the tracking was pretty solid. It is assisted by a secondary telescope on the mount that helps the mount maintain good tracking, not just pre-knowledge of where the object will be.

The clouds are however much more of a problem than you're suggesting. One promising infrared band is around 10 microns, but a thick cloud will still scatter that. You'd need a 20cm wide laser beam at that wavelength for it to diverge to a beam width of around 10 arcseconds. Which is basically a reasonably-sized telescope, working in reverse.

Alternatively, you could go for millimeter waves, which would pass through the clouds reasonably well, but then you're well outside the realms of "laser" and into the standard directional dish antenna. And it'd have to be a very large dish to give you a narrow beam. For instance, a rather unsubtle 2 metre wide dish with a 1mm wavelength will give a beam that diverges by 100 arcseconds. And there will probably be omnidirectional leakage which the dastardly authorities are likely to be able to detect. At least visible and infra-red leakage can be easily blocked and concealed, but radio is much harder.

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