I have to give a laptop to my 4 yr old who lives very far away from me, so that we can have regular video chats. I want to restrict any other use for that laptop, including video chats with other users. Specially, I am afraid she could play around with the keyboard and accept an incoming call from who-knows in the internet while her grandparents are fully unaware of what is happening.
Is there any way (using e.g. the ubuntu firewall) to restrict any video chat with anyone else other than me (I use google hangouts or skype or any other thing you may suggest).