Firewall - Network profiles

You can select the default profile (i.e. Public/Private mode) for each network saved in the list.

When Enable automatic profile switching is checked, Avast automatically changes your firewall mode to the profile specified when you connect to a network in the list.
If you check the box for Show notifications about automatic profile switching, Avast displays a message when you connect to a network and the firewall profile changed (i.e. from Private to Public mode).
You can also provide greater connectivity for networks which present low security risk by checking the box in the Friends column.