Prevent background apps from one user accessing internet on another user’s Wi-Fi on MacBook?

That's not a realistic expectation.

The machine has one WiFi connection at a time. It's not user specific. If you use fast user switching, the account in the background may continue to poll the internet for things like email, etc.

There's no easy way to deal with this.

The simplest thing I can think of is do NOT use fast user switching.

Log out all users on the Mac. Select the wifi network to connect to at the log in screen, then log in with the appropriate user. When done with that, log out, select the network you want, and log in with the user appropriate to that network.

Or, do NOT use your personal machine for company business.

Eugen_Kr wrote:

• Specifically, I don’t want any work-related app or background process to use my home Wi-Fi or reveal my home IP address while I’m working in the personal user session.

As KiltedTim suggests, being logged into only one account at a time is a potential solution. However, if you intend to log into your work account from your home, how will you connect to the Internet? I suppose if you have a work-issued phone you could tether that.

Personally, I find it easier to have separate Macs for work and personal use. There's a bit of blending in that my work Mac is signed into my Apple Account, but I maintain some separation because I use the native Mail and Calendar apps for personal accounts and Outlook for work accounts.

It should be possible, yes. You will just have to be careful about which wifi network is connected before you log in. You may also have to pay attention to what network gets connected if the machine sleeps, then wakes. I'll have to experiment to see if different users can have different preferred network settings.

From the sound of it, I'm assuming the OP may have two completely different internet connections available, each with its own wifi network.

Example, my wife used to work for a large hospital that provided internet service with a secure router set up with a hardware based point to point vpn for remote staff. Of course, in their case, they also had MAC address filtering set up on that router so that it was only possible to connect the company issued laptop to it...

I'd be interested in hearing more details of exactly how things are set up for the OP. The request may end up being meaningless if all they only actually have one ISP connection.

Makes sense, I missed the statement, "Each account has its own Wi-Fi network and time zone settings." I've also worked in settings where I had access to PHI, and in those cases working in a secure environment on company-provided devices was a must. But use of those devices for personal activities was strictly against policy.

+1 👍