If I make a hotspot and connect my mobile to my laptop, can an ISP detect it?

I am running a hotspot using the create_ap bash script on Ubuntu. Is there any way for an ISP to detect the devices connected to a computer on which a hotspot is made?

Solution 1:

The ISP can't identify your devies directly, but it can detect them in several ways analyzing your traffic. For example, most of the browsers have a unique fingerprint that can be used to track it.

As far as I know, there is no infallible way to prevent your ISP from detecting your devices; still, there are some ways you can prevent it from reading the content your traffic, such as VPNs or Tor Browser. Those methods are not completely "anonymous" (for example, P2P connections can be identified without knowing their content) but they help you to hide a lot of information that are useful to track your online activity. Note that the ISP and whoever is able to intercept your traffic would find out that you are hiding them.

Anyway, it's worth noting that in most cases your ISP can't log nor analyze your internet activity without your consent, especially if you live in the EU.

I hope that my answer will be useful. If you provide some more information about why you are interested on the topic I might be able to give you a more detailed answer.

Solution 2:

They can sure see you're running a hotspot, and most ISPs which charge extra for it (cellphone companies) automatically block it unless you are paying for that service. They could also look at the http: traffic and see what kind of OS and browsers are in use, to make an educated guess about the type and number of systems using it.

Solution 3:

Yes, they can still detect it. They will be able to see the multiple MAC addresses. If you want to hide the number of machines accessing the internet from your router, you need to set up a SOCKS proxy server on your computer. The machines you want to hide will not recognize each other like they would on a LAN (most hotspot software creates an intranet between all connected devices), but they will be hidden.