Enable Strict-Transport-Security HTTP response header. HTTP Strict Transport Security (HSTS) header is proposed to prevent eavesdropping and man-in-the-middle attacks like SSLStrip, when a single non-HTTPS request is enough for credential theft or hijacking. It forces browser to connect to the server in HTTPS-mode only and automatically convert HTTP links into secure before sending request. <a href=":wiki">@wiki</a> has more information about HSTS