How to disable URL sharing On macOS High Sierra (perhaps also earlier version of macOS), I noticed that when I open a URL in a webbrowser (tested with Safari and Opera), that on other Macs in the local network, the Docks shows an additional icon of the local browser on the left hand side. When I click this icon, it opens the URL that is open on the other Mac.



I have three questions: How does this (technically) work, how is this feature called, and how do I disable it?

As for the technology, I assumed that the URL of the frontmost browser window would be shared using a discovery service (DNS-SD, formerly Bonjour), but I couldn't detect it with a Bonjour browser. My second thought is that it is some kind of AirDrop technology, but I couldn't find it there either. So I'm not sure if this is sharing on a local LAN, or sharing using the same iCloud account.
It's called Handoff &amp; is part of Continuity, enabling seamless working between all your devices.

As far as its underlying structure, Continuity uses Bluetooth, WiFi &amp; internet connectivity, all linked via your iCloud account.
Handoff itself requires Bluetooth, so works at short distance only.


  Turn Handoff on or off
  
  Note: If you don’t see a Handoff option on your device, it doesn’t
  work with Handoff.
  
  
  On your Mac: Choose Apple menu  > System Preferences, click General, then select “Allow Handoff between this Mac and your iCloud devices”
  (below “Recent items”). To turn it off, deselect the option.
  On iPad, iPhone or iPod touch: Go to Settings > General > Handoff, then tap to turn on Handoff. To turn it off, tap the option.
  On Apple Watch: Open the Watch app on iPhone, go to My Watch > General, then tap to turn on Enable Handoff. To turn it off, tap the
  option.