I have an iMac in my office which is connected to the eduroam network (which is a common network in universities). When I am not in the office, I can use the Apple's application Screen Sharing to connect to the iMac through my MacBook Pro.
In the "Sharing" panel of the iMac settings I have just "Screen Sharing" selected, and I allow just administrators to connect. Then, I just have to copy the vnc string I find in the same folder inside the Screen Sharing application, insert the credentials of the iMac, and it works.
You can have a look at the Sharing panel in my settings. It's from here that I get the vnc path to connect to the iMac.
I have another laptop, a MacBook Air, that is at home, connected to my personal router. If I am on a different network, always with my MacBook Pro, and I try to use Screen Sharing in the same way to connect to the MacBook Air, it doesn't work. For this second computer, the Screen Sharing App works only if I am on the same network of the MacBook Air.
Does anyone know what are the difference between the two computers and why I can connect to the iMac and not to the MacBook Air? Thanks in advance for your help!
In case it's not possible to do that through the use of the vnc, maybe it can be done by specifying the Apple ID, but in that case someone on the other side should accept my request to control the screen. Is there a way to do it automatically?