Context: location

This directive specifies that the location block is internal. In other words, the specified resource cannot be accessed by external requests:

server { 
    [...] 
    server_name .website.com; 
    location /admin/ { 
        internal; 
    } 
} 

With the previous configuration, clients will not be able to browse http://website.com/admin/. Such requests will be met with 404 Not Found errors. The only way to access the resource is via internal redirects (check the Rewrite module section for more information on internal redirects).