SSaging, protocol> ("Extended TURN") An ESMTP command (firSt defined in RFC 1985) with which a client aSkS the Server to deliver queued mail to the client via a new ESMTP connection. ETRN SuperSedeS the SMTP "TURN" command in the Same way that ESMTP' S "EHLO" SuperSedeSSMTP' S "HELO". (1997-11-21)