You can configure here limitations on access rate to this peer search interface by unauthenticated users and users without extended search right (see the Accounts configuration page for details on users rights).
Access rate limitations to this peer search interface. When a user with limited rights (unauthenticated or without extended search right) exceeds a limit, the search is blocked.
Access rate limitations to the peer-to-peer search mode. When a user with limited rights (unauthenticated or without extended search right) exceeds a limit, the search scope falls back to only this local peer index.
Access rate limitations to the peer-to-peer search mode with browser-side JavaScript results resorting enabled (check the 'Remote results resorting' section in the Search Portal configuration page). When a user with limited rights (unauthenticated or without extended search right) exceeds a limit, results resorting becomes only applicable on demand, server-side.
Limitations on snippet loading from remote websites. When a user with limited rights (unauthenticated or without extended search right) exceeds a limit, the snippets fetch strategy falls back to 'CACHEONLY' (check the default Snippet Fetch Strategy on the Search Portal configuration page).