Why can sites know my LAN connected devices?

[Gat Pelsinger]

On sites like YouTube, there exists a "Play on TV" option. I feel that very insecure. How do sites know what devices are connected on my LAN? Is there a way to disable this?

 

I think this even happens when using VPN but I use browser level VPN.

[HanZie82]

Your TV sends out signals "hey im a TV" And your phone listens and puts it on the list.
Just because you are on the same wifi.

Only to make it very easy for you to play stuff on your TV from your phone.

 

 

Also, next time please be more specific, tell us waht hardware you use, what you expect and not have us guess.
Clearly you've been here before, you should know better.

[Gat Pelsinger]

@HanZie82

 

Why does my hardware matter in this context? It's a website, it's same (almost) on every device. But that still doesn't explain my real question, that is, is there a way to disable this feature?

 

Btw, don't get mad again, I am on Windows.

[HanZie82]

Im not mad. Or am I.
But Every device is different.
But this has very little to do with the website and more with the devices you're using and how they are connected to most likely the same wifi.
The TV is discoverable for your device, the website can only see if that connection is there or not and if so use it.

But im not too knowledgable about it, you can maybe read up on it here: https://en.wikipedia.org/wiki/Google_Cast

And might even find a way to disable it if needed, but knowing Google im not sure of possible.

Sorry i cant be of more help.

ps there is no emotion in text, so i expect none either way. (ok besides the emoticons then )

[tikker]

19 hours ago, Gat Pelsinger said:

I feel that very insecure. How do sites know what devices are connected on my LAN?

They don't. In the case of YouTube, the most likely explanation is that your TV announces to the network it's connected to that it supports casting. YouTube picks up on that and thus provides you the option.

  

18 hours ago, Gat Pelsinger said:

Why does my hardware matter in this context? It's a website, it's same (almost) on every device.

It's the hardware that is communicating their presence and making it available. YouTube the site doesn't know about them. They have either been linked using a link code in the past or the devices themselves are simply announcing they can be cast to and some code is making that available. My Nvidia Shield is on the same network as my PC and phone, for example, so both are able to cast to them. If I disconnect my phone from the Wi-Fi and go to mobile data the Shield disappears as well, because it's no longer on the same network, showing that the site doesn't inherently know my device is there.

 

 

19 hours ago, Gat Pelsinger said:

Is there a way to disable this?

If you don't use it, maybe your TV (or whatever the device is) has an option to disable casting?