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Comment by moondowner | Hacker News Reader

There's an easy way to do that: when the browser makes a request to some web site, the server serving it will detect the browser's user agent (which the browser sends with the request to the server) and will check the operating system specified. If it's Windows 10 - don't fulfill the request.

Here's a random example of user agent detection http://stackoverflow.com/questions/6163350/server-side-brows...

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They are talking about trackers, not anything web based. So unless a client announces the underlying operating system there shouldnt be any way to implement such a block.

They are talking about private trackers. All of these trackers have their own website and that is the only way to get access to the lists of torrents.

Not that the average user necessarily knows this, but in principle can't the user agent string sent by the browser be spoofed?

Sure, but its not about user agents.

How else would you detect the operating system of the client making the request?

I have no idea if the the trackers are doing this or not, but you could use TCP/IP stack fingerprinting. It's a bit costly, so I doubt it's in use. But it could be one way to achieve it. It's certainly not 100% accurate, but my experience with nmap is the detection works surprisingly well:

https://nmap.org/book/man-os-detection.html

That requires the server to be able to make network requests to the host - not gonna happen for most users busting your site.

Only if you use nmap as-is. Also majority of torrent software uses UPnP IGD to open TCP port (which is then advertised to the tracker).

I’m not sure but I think µTorrent on Windows also listens on the Toredo provided IPv6 address.

What do you think it's about, then?

Sure but chances are that 90% of the users don't know how to do it. Also it's a good warning for the users. It's primarily not for protecting the torrent site but for protecting the users anyway.

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