Wi-Fi encryption is generally used to stop unintended people snooping on your Wi-Fi traffic, however, by default all users that are legitimately connected to a Wi-Fi network may be able to see each others network traffic. Most Wi-Fi systems have a feature known as ‘client isolation’ which, once enabled, blocks users from accessing information destined for another user. Sometimes this can be controlled at a wireless access point level or network level. The more advanced configurations can in effect only allow a user access to the internet and block access to any other internal devices or services.
Although client isolation is an effective technique on a local Wi-Fi network it is not intended as a replacement for technologies such as VPN (Virtual Private Network) where an encrypted end-to-end tunnel is created. Client isolation is particularly useful for blocking peer-to-peer services on a large network.