Ng, protocol> ("ExteNded TURN") ANESMTP commaNd (first defiNed iNRFC 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" supersedes SMTP' s "HELO". (1997-11-21)