turn off sharing network details between iOS devices?

[wackymacky]

A "feature" of iOS10 and macOS now, I've just noticed, is to auto-join networks across all devices if wifi is turned on if you sign in with one device.

Is there a way to turn this off?

If I log on to a free (and therefore often somewhat insecure) wifi network, I routinely use a VPN.

I noticed the other day however that when I joined a airport lounge wifi with my laptop at the airport, (and was securing the macbook data with a VPN) my phone signed it self into this non encrypted using the wifi password I entered on my macbook, and was happily sending packets of email data etc from my pocket without me knowing.

 

[I7guy]

A "feature" of iOS10 and macOS now, I've just noticed, is to auto-join networks across all devices if wifi is turned on if you sign in with one device.

Is there a way to turn this off?

If I log on to a free (and therefore often somewhat insecure) wifi network, I routinely use a VPN.

I noticed the other day however that when I joined a airport lounge wifi with my laptop at the airport, (and was securing the macbook data with a VPN) my phone signed it self into this non encrypted using the wifi password I entered on my macbook, and was happily sending packets of email data etc from my pocket without me knowing.

Can't you turn on, "ask to join networks"?

 

[C DM]

A "feature" of iOS10 and macOS now, I've just noticed, is to auto-join networks across all devices if wifi is turned on if you sign in with one device.

Is there a way to turn this off?

If I log on to a free (and therefore often somewhat insecure) wifi network, I routinely use a VPN.

I noticed the other day however that when I joined a airport lounge wifi with my laptop at the airport, (and was securing the macbook data with a VPN) my phone signed it self into this non encrypted using the wifi password I entered on my macbook, and was happily sending packets of email data etc from my pocket without me knowing.

That sounds more like Keychain and has been around for some time. Try turning that off if it's enabled in iCloud settings.

 

[Justaguy48]

Just kept wifi turned off until you want to use it. I am in the same boat as you, using VPN on unsecure networks. I just keep phone, and iPad for that matter, wifi off until I'm at home, or work network with secure wifi.

 

[chrfr]

A "feature" of iOS10 and macOS now, I've just noticed, is to auto-join networks across all devices if wifi is turned on if you sign in with one device.

Is there a way to turn this off?

These are shared via the iCloud keychain. If you disable that, the devices will stop sharing network information, but you'll also lose sharing of passwords and logins.
Edit: just realized that @C DM posted this already.