title: best location to deny user agent in nginx for all sites
body: <p>I would like to deny access to a user agent for all my sites without having to repeat the statement below in every server block. Is this possible?</p>
  
  <pre><code>if ($http_user_agent ~* ^.*UnWelcomeUserAgentString.*$){
      return 403;
  }
  </code></pre>