My brother is my neighbor and we are saving some money sharing internet, but I don't want to share anything else, just internet.
What I did is to pass a cable through the wall that connects his router —that has access to internet— to my router. I created my own wifi name and password.
Today my brother-in-law has been listening to online radios and I had the notification in my android phone telling me that someone was casting in a wireless sound system.
I checked my router entering its IP in the explorer url box and saw that someone "unknown" was connected to my network.
I would like anything connected to my wifi to stay in a different network, being not able to see what my brother is doing (and vice-versa)
How should I start?